1,639 research outputs found
Lepadella hanneloreae Luo & Segers 2020, n. sp.
No full text<i>Lepadella hanneloreae</i> n. sp. <p>Figures 5 a–c, I-4</p> <p> <b>Type locality.</b> Lohulu River near Bomane, DR Congo 24 May 2010 (KM49, KM48); a few specimens from Yangambi primary forest, DR Congo, 11 June 2012 (Y25). Numerous additional specimens in the samples from the type locality.</p> <p> <b>Material examined.</b> Holotype: female specimen in permanent slide, deposited in RBINS (RIR.292); Paratypes: seven permanent slides containing one female specimen each, deposited in RBINS; five permanent slides containing two female specimens each, deposited in RBINS (RIR.293 to RIR.304), one permanent slide containing three female specimens, deposited in CSB-UK.</p> <p> <b>Differential diagnosis.</b> <i>Lepadella hanneloreae</i> <b>n. sp.</b> is strikingly similar to <i>L. amazonica</i> Segers, 1993 (in Segers <i>et al</i>. 1993b). The two differ by the dorsal carinae on the lorica: in <i>L. hanneloreae</i> <b>n. sp.</b> there is one pair of middorsal and one pair of lateral carinae, whereas in <i>L. amazonica</i> there are two pairs of closely adjacent lateral carinae. Furthermore, the new species is probably related to <i>L. berzinsi</i> Segers, 1993, but the latter has three pairs of more pronounced carinae situated at regular distances from each other.</p> <p> <b>Description.</b> Parthenogenetic female (male unknown): Lorica elongate, roughly egg-shaped, width about two thirds of length. Ventral lorica flat, dorsal domed, lorica about twice as wide as high. Head aperture ventrally a deep V-shaped sinus, dorsally semi-circular in anterior view, straight in ventral view, with stippled collar. Dorsal lorica with two pairs of longitudinal carinae: one median pair, fused in the distal third of the lorica, one lateral pair running from behind the collar to approximately level of the apertures to the dorsal antennas. Lateral edges of lorica smooth, evenly curved, posterior edge nearly straight or with a shallow median notch. Apertures to the lateral antennas situated at the level of the anterior margin of the foot aperture, arranged symmetrically about medially from the fused median carinas to the lateral margin of the lorica. Foot aperture elongate, lateral margins nearly parallel. Foot with three distinct pseudosegments, the distal one about twice as long as the second, bearing a dorsal sensory groove near its basis. Two equal toes, these evenly tapering to distally.</p> <p> <b>Measurements</b> (n=10). Lorica length: 91–106 (100), width: 60–70 (67); head aperture width: 23–37 (29), head aperture depth dorsally: 7–14 (10), ventrally: 19–24 (21); foot aperture width: 18–20 (19), length: 23–33 (27), toe length: 22–29 (25).</p> <p> <b>Etymology.</b> The specific name is as a noun in the genitive case, after Mrs Hannelore Segers, daughter of the second author of this paper.</p>Published as part of <i>Luo, Yongting & Segers, Hendrik, 2020, Eight new Lepadellidae (Rotifera, Monogononta) from the Congo bring to level endemism in Africa's rotifers, pp. 371-387 in Zootaxa 4731 (3)</i> on pages 374-376, DOI: 10.11646/zootaxa.4731.3.6, <a href="http://zenodo.org/record/3653632">http://zenodo.org/record/3653632</a>
Lacinularoides Meksuwan, Pholpunthin & Segers, 2011, new genus
No full textGenus Lacinularoides, new genus (Figs 4–5) Type species. Lacinularoides coloniensis (Colledge, 1918), new combination Differential diagnosis. The new genus is characterized by having a corona consisting of five or seven lobes and by the absence of an oviferon (egg-carrying organ). Although the size of the animals and their corona shape both remind one of Pentatrocha Segers & Shiel, 2008, they are separated from this genus by the absence of an oviferon and presence of obvious gelatinous matrix formation, and by the coronal lobes being much smaller than in Pentatrocha. While Pentatrocha has never been observed other than solitary, the single constituent species of Lacinularoides is colonial. By lacking an oviferon, which we consider a synapomorphic feature for a [Pentatrocha, Sinantherina Bory de St. Vincent, 1826] clade, and by having a corona exhibiting distinct lobes, we surmise that the taxon is closest to Octotrocha Thorpe, 1893, which has an even more intricately lobed corona. We further believe the new genus is close to Lacinularia Schweigger, 1820, which has a very similar morphology but which has a corona that has, at the most, a ventral concavity giving it a heart-shaped appearance (see Table 4). Description. Mature female large, foot long, foot peduncle tiny or almost invisible. Corona large, with five prominent and two small lobes: a large pair of ventral lobes separated by a deep ventral sinus; a pair of small or, occasionally, indistinct lateral lobes and three dorsal lobes. Single species known to date, living sessile in small to large colonies, occasionally solitary (first specimen of newly established colony?), inhabiting a clear to light-brown coloured gelatinous case. Trophi malleoramate. Etymology. The name Lacinularoides (gender: masculine) is derived from that of its relative, Lacinularia. Redescription of Lacinularoides coloniensis (Colledge, 1918), n. comb. Animal large, transparent, internal organs obvious. Trunk fusiform, tapers gradually into tapering foot, neck region slightly curved dorsally when animal expands the corona. Foot long, with abundant foot glands along upper half part, peduncle tiny. Extended corona large, five- to seven-lobed, consisting of a conspicuous pair of ventral, a pair of occasionally indistinct lateral, and three dorsal lobes. The lobes of the ventral pair are rather round, held perpendicular to the longitudinal axis of the body; the lateral lobes are relatively small and appear to be made up by an S-shaped curve of the lateral corona margins. The dorso-lateral lobes are round but with rather straight latero-dorsal sections, tilted to ca. 60 degrees versus the body axis and slightly bent to ventrad; the middorsal lobe relatively small but distinct, slightly triangular. Ventral lobes separated by a deep, U-shaped sinus, separation of dorsal and especially lateral lobes shallow. Dorsal gap tiny; apical field surface bulged by the large mastax. Small projection bearing the dorsal antenna under the dorsal corona lobe. Lateral antenna on minute conical papillae. Gelatinous matrix clear to light-brown, containing the eggs, if any. Male: see Colledge (1918). Trophi nearly symmetrical, malleoramate; unci teeth strongly differentiated. Proximal unci teeth on both sides with three strong teeth, the first smallest in size, the first tooth on the left side bigger than on the right; distal unci teeth of both sides weak, relatively few (2–3). Mature females total length ca. 1,300 µm. Trunk length ca. 460 µm, width ca. 130 µm. Foot length ca. 820 µm. Corona height ca. 380 µm, width ca. 360 µm. Parthenogenetic egg size ca. 160 x 100 µm. Remarks. Although we recognize this taxon as representing the genus newly described herein (with the caveat that the diagnosis of genera in Flosculariidae is in urgent need of revision; see comment in Segers & Shiel 2008), the species appears to have been recorded repeatedly before. We accept that the present material is conspecific with the animal described in good detail in 1918 by W. R. Colledge, as Melicerta coloniensis, from a “pool at Goodna, Qld” (Colledge, 1925) Australia. The taxon had not been recorded ever since and it appears to have been overlooked. The reason for this may be historical, and lay in confusion between L. coloniensis and Octotrocha speciosa. We know from the study of W.T. Edmondson’s notebooks that this author, an authority on sessile rotifers, considered both O. speciosa and L. coloniensis as possible identity of animals before him. We now know that the two can relatively easily be distinguished, even in contracted state, by their trophi morphology, a feature that at that time was hardly considered in identification of sessile rotifers: the differentiation in development of the unci teeth is noticeably stronger in L. coloniensis than in O. speciosa (compare Figs 5 a–c with Fig. 7 in Segers et al., 2011). Based on a re-evaluation of published drawings and photographs of trophi morphology, Segers et al. (2011) reevaluated previously published and (partly) illustrated records of Octotrocha speciosa Thorpe, 1893 by Edmondson (1959), Koste (1974, 1978, 1989), Sarma & Elias-Gutierrez (1998), and Segers & Shiel (2008) as being misidentified, and with the information we now have available we suggest that these records all pertain to L. coloniensis. This would imply that, whereas both species co-occur in Southeast Asia and China, L. coloniensis is much more widespread and may be the only one of the two that occurs in Australia and the Americas. This precludes direct comparison of the two by zoologists working outside the area of O. speciosa, including W.T. Edmondson. Based on the present considerations, we now are quite sure that the glass model of a small colony of sessile rotifers identified as O. speciosa Thorpe, on exhibit in the American Museum of Natural History (see Fig. 1.1. in Wallace et al. 2006) and whose identity had already been questioned by Segers & Shiel (2008), represents L. coloniensis. Similarly, as our observations confirm Octotrocha speciosa as a solitary animal, we assume that the autorecruitive nature of colony formation of O. speciosa as reported by Wallace et al. (2006) refers to L. coloniensis. Indeed, a photograph kindly supplied by R.L. Wallace of the animals he studied indeed appears to depict L. coloniensis.Published as part of Meksuwan, Phuripong, Pholpunthin, Pornsilp & Segers, Hendrik, 2011, Diversity of sessile rotifers (Gnesiotrocha, Monogononta, Rotifera) in Thale Noi Lake, Thailand, pp. 1-18 in Zootaxa 2997 on pages 8-12, DOI: 10.5281/zenodo.20799
Lepadella jingruae Luo & Segers 2020, n. sp.
No full textLepadella jingruae n. sp. Figures 6 a–c, I-5 Type locality. Lohulu River near Bomane, DR Congo 24 May 2010 (KM48, KM49). Material examined. Holotype: one female specimen in permanent slide, deposited in RBINS (RIR.305); Paratypes: six permanent slides containing one female specimen each, deposited in RBINS (RIR.306 to RIR.311), one permanent slides containing one female specimen and one permanent slide containing two female specimens in CSB-UK; one permanent slide containing two female specimens, deposited in SHNU. Differential diagnosis. The relatively flat lorica of L. jingruae n. sp. places the species in the vicinity of L. ovalis (Müller, 1786) and L. eurysterna Myers, 1942. The new species is diagnosed from both by the remarkable protruding projections laterally of the head aperture, and further from L. ovalis by its smaller size and posteriorly rounded lorica (relatively large and with a sharply set-of posterior concavity in L. ovalis). Lepadella jingruae n. sp. can easily be distinguished from species of the L. patella— complex, including the similarly rounded L. discoidea Segers, 1993 by its flat lorica and the protruding lateral projections of the head aperture. Differential diagnosis. Parthenogenetic female (male unknown): Lorica rounded, about as wide as long. Ventral lorica flat, dorsally with a central dome, lateral parts strongly flattened, lorica about thrice as wide as high. Head aperture ventrally a deep V-shaped sinus, dorsally semi-circular in anterior view, broadly U-shaped in ventral view, with weak collar. Anterior of lorica protruding into a pair of well-developed, sharp projections. Lateral margins of lorica smooth, evenly curved, posterior edge convex. Dorsal lorica smooth, without markings. Apertures to the lateral antennas situated slightly posterior the level of the anterior margin of the foot aperture, arranged symmetrically about medially from median axis to the lateral margin of the lorica. Foot aperture elongate, lateral margins diverging to posteriorly. Foot with three distinct pseudosegments, the distal one about twice as long as the second, bearing a dorsal sensory groove near its basis. A pair of equal-sized toes present, these almost parallel-sided basally, more strongly tapering from about midway to distally. Measurements (n=10). Lorica length: 100–110 (106), width: 90–101 (93); head aperture width: 25–31 (28), depth dorsally: 15–21 (18), depth ventrally: 24–28 (25), foot aperture width: 15–19 (18), length: 26–31 (28), toe length: 26–29 (29). Etymology. The specific name is as a noun in the genitive case, after Miss Jingru Zhu, daughter of the first author of this paper.Published as part of Luo, Yongting & Segers, Hendrik, 2020, Eight new Lepadellidae (Rotifera, Monogononta) from the Congo bring to level endemism in Africa's rotifers, pp. 371-387 in Zootaxa 4731 (3) on page 376, DOI: 10.11646/zootaxa.4731.3.6, http://zenodo.org/record/365363
Dr. Edwin Wright Collection: Jessica B. Watson (nee Segers)
No full textNotes - Mrs. Jessica B. Watson writes about her family life in Athabasca. Her father, Captain F. S. Segers, worked for the Hudson's Bay Company and was "in charge of all of the boat transportation up and down the river." Mrs. Watson speaks of travelling, pets, entertainment, and daily life in Athabasca, where she arrived ,via stagecoach and buckboard, when she was 16 years old, in 1891 (1 page
Hemodynamics and wall shear metrics in a pulmonary autograft : comparing a fluid-structure interaction and computational fluid dynamics approach
No full textObjective: In young patients, aortic valve disease is often treated by placement of a pulmonary autograft (PA) which adapts to its new environment through growth and remodeling. To better understand the hemodynamic forces acting on the highly distensible PA in the acute phase after surgery, we developed a fluid-structure interaction (FSI) framework and comprehensively compared hemodynamics and wall shear-stress (WSS) metrics with a computational fluid dynamic (CFD) simulation. Methods: The FSI framework couples a prestressed non-linear hyperelastic arterial tissue model with a fluid model using the in-house coupling code CoCoNuT. Geometry, material parameters and boundary conditions are based on in-vivo measurements. Hemodynamics, time-averaged WSS (TAWSS), oscillatory shear index (OSI) and topological shear variation index (TSVI) are evaluated qualitatively and quantitatively for 3 different sheeps. Results: Despite systolic-to-diastolic volumetric changes of the PA in the order of 20 %, the point-by-point correlation of TAWSS and OSI obtained through CFD and FSI remains high (r > 0.9, p 0.8, p < 0.01) for OSI). Instantaneous WSS divergence patterns qualitatively preserve similarities, but large deformations of the PA leads to a decrease of the correlation between FSI and CFD resolved TSVI (r < 0.7, p < 0.01). Moderate co-localization between FSI and CFD is observed for low thresholds of TAWSS and high thresholds of OSI and TSVI. Conclusion: FSI might be warranted if we were to use the TSVI as a mechano-biological driver for growth and remodeling of PA due to varying intra-vascular flow structures and near wall hemodynamics because of the large expansion of the PA
Een (bio)mechanische analyse van stentgraftimplantaties voor het behandelen van aneurysma's van de abdominale aorta
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Wave reflection assessment via flow wave approximation: triangular versus population-based waveform
No full textTargeted drug delivery for liver cancer: a patient-specific computational model of the particle transport during radio-embolisation
No full textHepatocellular carcinoma is the most common liver malignancy and it is predicted to grow to 22 million cases over the next two decades. Depending on the stage of the tumour, the therapy is chosen based on the Barcelona clinic liver cancer (BCLC) criteria. Transarterial therapies are among the possible treatments and they can be divided into transarterial embolization (TAE), transarterial chemoembolization (TACE) and radioembolization (RE). These therapies take advantage of the fact that the tumours are mostly fed by hepatic arteries instead of by hepatic veins as healthy tissue does. In this context, Computational Fluid Particle Dynamics (CF-PD) have been proven to be a powerful tool to evaluate how to maximize the targeting to the tumours as well as to asses which parameters play the most significant role in the final distribution of the drugs. Also, this technique can be used to generate particle release maps (PRMs) that link the injection points with the path that the particles will follow. Thus, they can be used to decide the injection point to target the tumours.
In this work, the possibility of targeting the tumours in a patient-specific geometry by means of CF-PD has been evaluated as well as the parameters that play the most significant role in the final distribution of the drugs. For this purpose, the geometry of the patient was extracted from Magnetic Resonance Images (MRI) by means of segmentation and computer simulations were run in it. For this patient-specific geometry, it was proven that assessing which treatment would provide the easiest target to the tumours is more than feasible by means of CF-PD. Also, that the injection location plays a significant role in terms of particle distribution and the particle density and particle diameter in terms of distal penetration. Even if the particle distribution obtained in the simulations seems to have some similarities to the ones obtained in reality, images with better resolution are needed to further assess this aspect
Multi-level modelling of hepatic perfusion in support of liver transplantation strategies
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