Portion Of Wall Research Articles

Irreversibility analysis for the natural convection of Casson fluid in an inclined porous cavity under the effects of magnetic field and viscous dissipation

The non-Newtonian fluids are increasingly being employed in various engineering and industrial processes. The Casson fluid model is also used to characterize the non-Newtonian fluid behavior and has great importance in polymer processing industries and biomechanics. Motivated by these developments, the present study explores the entropy generation for the natural convection of Casson fluid in a porous, partially heated square enclosure considering the effects of horizontal magnetic field, cavity inclination and viscous dissipation. The bottom wall of the enclosure is considered partially heated, whereas the left and right walls are taken as cold at constant temperature. The top wall and the remaining portions of the bottom wall are adiabatic. The dimensionless form of the governing conservation laws is simulated via higher order Galerkin finite element method. Particularly, the discretization is performed using biquadratic elements for velocity and temperature components whereas the discontinuous linear elements employed for the pressure. The discretized nonlinear systems are handled by implementing the adaptive Newton-multigrid solver. In order to increase the reliability of the computed results, the designed solver is validated qualitatively and quantitatively for the available numerical and experimental data. The simulated results are analyzed through isotherms, streamlines and two dimensional plots. Moreover, the average entropy generation, kinetic energy and temperature are also computed and analyzed. The controlling parameters are Hartmann number (Ha=0−100), Darcy number (Da=10−4), Prandtl number (Pr=7), Rayleigh number (Ra=105), Casson fluid parameter (γ=0.1−10), cavity inclination (ϕ=0°−90°) and Eckert number (Ec=10−6−10−4). It is concluded that the average heat transfer rate decreases whereas the total entropy generation increases by increasing the cavity inclination (ϕ) for each value of Ha. Further, the irreversibilities due to heat transfer and magnetic field both are increasing for function of ϕ.

Detectable reentrant circuits in localized microreentrant tachycardias in the era of ultra high-density mapping

Abstract Funding Acknowledgements Type of funding sources: None. Background Optimal criteria in clinical practice differentiating microreentrant atrial tachycardias (mAT) from macroreentrant atrial arrhythmias (MAT) have not yet been clarified. The use of multielectrode catheters and the recent development of ultra high-density mapping (UHDM) with automated features has improved our knowledge of mAT circuits and foci location. Purpose In the present study, we systematically evaluated AT mechanisms in a large consecutive cohort of patients with MAT identifying the precise mAT circuits using the Rhythmia mapping system. Methods Consecutive patients indicated for MAT ablation from January 2021 to November 2021 at 33 centers were prospectively included. All MATs were completely mapped in the left or right atrium by means of the Rhythmia mapping system and the 64-poles Orion basket catheter. For study purpose, a mAT was defined as an AT with slow continuous low fragmented potentials covering at least 50% of tachycardia cycle length (CL) in a small area (set as a circuit within < 1 cm2) and in a couple of closed splines of the Orion catheter and a centrifugal activation pattern to the remainder of the atria. The Lumipoint tool was systematically used to confirm EGM fragmentation inside this area. Data are reported as mean±SD. Results One-hundred eighty-seven MATs were analyzed: 100 (53.7%) atypical left atrial flutter, 27 (14.3%) left AT and 60 (32%) right AT. A total of 7 MAT (prevalence of 3.7%) was identified as mATs (6 atypical left atrial flutter and 1 AT), with 5 out 7 with a previous history of AF ablation procedure. The percentage of atrial surface with a voltage level below 0.1 mV was 19±17%. The CL was 329±78ms. The electrical activity spanning the whole CL was detected by 2±0.6 pairs of close bipoles of the Orion catheter, and was actually confined to a region of 0.4±0.2cm2 with continuous highly fractionated potential covering 68±10% of the CL (longest component of fractionated EGM per spline=74±18% of the CL). Voltage level was 0.3±0.1mV at RF delivery site and 0.2±0.1mV at the site of longest duration of the fragmented potential, respectively. Targeted mAT activity was identified closer to PVs in three cases and at the mid portion of the anterior wall and at the roof in two cases each, respectively. In all cases a single shot RF delivery terminated each arrhythmia at targeted location. Consolidative RF ablations were then delivered in the adjacent area. No complication occurred. At three months follow-up all patients remained free from any AT recurrence. Conclusions In this standard of care clinical experience with UHDM system, the prevalence of mAT seems to be higher than previously reported in literature. A technique based on mAT identification through a novel automated algorithm and matched area of electrogram fractionation captured by the Orion catheter may limit the extent of ablation needed.

P106 A LEFT GIANT MYXOMA WITH A NOTABLE NEOVASCULARIZATION

Abstract A 73–year–old asymptomatic woman came to our observation to perform a routine echocardiographic examination. The patient suffered from arterial hypertension, dyslipidemia, hypothyroidism, paroxysmal atrial fibrillation. She underwent a bilateral mastectomy for breast cancer about 5 years ago, and she was undergoing chemotherapy and radiation therapy for a stage IV lung adenocarcinoma. The clinical evaluation was normal, as was the electrocardiogram. Transthoracic echocardiographic evaluation showed the presence of a rounded formation with variable echogenicity, with an irregular surface (4 x 3 cm), adherent to the interatrial septum at the level of the fossa ovalis, which did not hinder the excursion of the mitral valve. No other significant cardiac abnormalities were detected. Tansesophageal echocardiography confirmed the presence of atrial mass adhered to the oval fossa (panels A, B). of coarsely rounded shape, and variable echogenicity, in the absence of interference with the movement of the valve leaflets and of anomalies of the interatrial septum (panel C). Coronary angiography showed a right–dominant coronary circulation (panel D) and a mild stenosis of the mid left anterior descending artery. An abundant arterial perfusion of the atrial mass, with several vessels originating from the circumflex artery was also evident at the coronary angiography (panels E, F). The patient underwent cardiac surgery; the surgical exeresis of the left atrial mass was performed through right mini thoracotomy. Because the neo–formation was adherent not only to the atrial septum but also to the left atrial roof, to obtain a radical excision, a large portion of the atrial wall and the septum were removed and totally reconstructed with the pericardium. The main artery supplied the mass related vascular network was ligated. The post–operative course was uneventful, and the patient was discharged at home on day six. The pre–discharge echocardiography showed absence of any residual mass in left atrium that appear anatomically reshaped, no shunt at level of interatrial septum, preserved ventricular function of both ventricles. Histological analysis confirmed the diagnosis of atrial myxoma. At six–month follow–up the patient was asymptomatic and the echocardiography was superimposable to discharge.

Echocardiographic Assessment of Mitral Annular Disjunction With Cross-Correlation by Computed Tomography and Magnetic Resonance Imaging: A Case Series

Mitral valve (MV) pathology, along with its associated peripheral anatomy, is one of the most common categories of heart disease. Two-dimensional (2D) transthoracic echocardiography (TTE) plays a prominent role in the detection and management of various types MV disease, specifically mitral annular disjunction (MAD). MAD is defined as a structural abnormality of the mitral annulus fibrosus, causing a noticeable gap between the atrial wall-mitral valve junction and the basilar portion of the left ventricular free wall (LV). The integral role that cardiac sonographers play in identifying MAD cannot be underscored, as well as the risk of easily overlooking this unique abnormality. Often associated with mitral valve prolapse (MVP), accurate documentation of MAD amid an echocardiographic study can have positive implications on patient prognosis. This case series highlights the echocardiographic characteristics of MAD, to raise awareness of this often forgotten feature of myxomatous mitral valves, which can indeed cause adverse patient outcomes. It is important to demonstrate correlational features with additional imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT).

Morphology, chemical composition and origin of 2:1 phyllosilicates in Bw horizons of latosols of the Brazilian Central Plateau: contribution to the discussion of the microgranular structure origin

Polished sections of two Bw horizons collected in latosols located on the South American Surface (LSAS) and the Velhas Surface (LVS) in the Brazilian Central Plateau were studied using backscattered scanning images (BESI) in scanning electron microscopy and energy dispersive spectroscopy (EDS). BESI showed areas with a strong microgranular structure associated with areas having a weak to moderate microgranular structure. BESI at high magnification also showed the presence of elongated particles 1 to 30μm long and 0.2 to 5μm wide, most of them exhibiting an internal layer organization of 2:1 phyllosilicate particles. Chemical composition determined using EDS showed that the core of the largest particles was consistent with the chemical composition of poorly weathered muscovite with a small proportion of Al in the interlayer space as hydroxy-Al. Results also showed that when the K 2 O content decreased, indicative of a stronger weathering of the primary minerals such as muscovite, the chemical analysis showed that the proportion of hydroxy-Al in the interlayer increased. From our results, it can be assumed that these particles correspond to weathered micas and hydroxy-Al interlayered vermiculites (HIVs) recognized earlier in the literature. They are interpreted as having been brought in the Bw horizons by the burrowing activity of termites and originating from deep horizons of the latosols studied or from the saprolite in which the latosol has developed. This explains their presence associated with minerals resulting from intense weathering of the mineral present in the parent material. In line with this interpretation, the strong microgranular structure of the Bw horizons results from fragmentation and transport activity while the weak to moderate microgranular structure corresponds to old portions of channels and cavity walls. Finally, our results show that some latosols should be considered as a biomantle in which the physical properties related to the microstructure development and chemical properties related to the presence of poorly to intensely weathered muscovites and of HIVs result from faunal activity.

Ovarian Follicular Growth through Intermittent Vaginal Gonadotropin Administration in Diminished Ovarian Reserve Women.

It is a challenge to obtain enough oocytes during in vitro fertilization (IVF) in women who have a poor ovarian response (POR) in achieving conception. We have adopted the characteristics of the first uterine pass effect, which we pioneered in employing the vaginal administration of gonadotropins in women receiving IVF treatments. In our previous study employing vaginal administration, faster absorption and slower elimination of gonadotropins were demonstrated, and, female subjects presented proper ovarian follicle growth and pregnancy rates. In this study, during 2016–2020, 300 to 675 IU of gonadotropins were administered vaginally every three days in 266 POR women for their controlled ovarian hyperstimulation (COH). The injections were performed with needles angled at 15–30° towards the middle-upper portions of the bilateral vaginal wall, with an injection depth of 1–2 mm. For the COH results, these women, on average, received 3.0 ± 0.9 vaginal injections and a total dose of 1318.4 ± 634.4 IU gonadotropins, resulting in 2.2 ± 1.9 mature oocytes and 1.0 ± 1.2 good embryos. Among these embryos, 0.9 ± 1.0 were transferred to reach a clinical pregnancy rate of 18.1% and a live birth rate of 16.7%. In conclusion, the intermittent vaginal administration of gonadotropins proved to be effective in POR women for their IVF treatments.

The Time Course of Monocytes Infiltration After Acoustic Overstimulation.

Cochlea macrophages regulate cochlea inflammation and may harbors the potentials to protect hearing function from injury, including acoustic overstimulation. Cochlea macrophage numbers increase at 3–7 days after acoustic stimulation. However, the exact timing of macrophage infiltration and maturation from inflammatory monocytes is unclear. Furthermore, neutrophils may also be involved in this process. Therefore, in this study, we investigated time-dependent immune cell infiltration, macrophage transformation, and neutrophil involvement following acoustic stimulation. Flow cytometry and immunofluorescence were conducted in C-X3-C motif chemokine receptor 1 (CX3CR1)+/GFP mice after acoustic overstimulation (at baseline and at 1, 2, 3, and 5 days after exposure to 120 dB for 1 h) to identify inflammatory monocytes in the cochlea. RNA-sequencing and quantitative polymerase chain reaction were performed to identify differentially expressed genes. Inflammatory monocytes infiltrated into the lower portion of the lateral wall within 2 days after acoustic overstimulation (dpn), followed by transformation into macrophages at 3–5 dpn via CX3CR1 upregulation and Ly6C downregulation. In addition, inflammatory monocytes were aggregated inside the collecting venule only at 1 dpn. Neutrophils were not a major type of phagocyte during this response. The gene encoding C-C motif chemokine ligand 2 gene was significantly upregulated as early as 3 h after acoustic overstimulation. Given these results, treatment to control immune response after a noise-induced hearing loss should be applied as soon as possible.

Investigation of local severe suction on the side walls of a high-rise building by standard, spectral and conditional POD

Local severe suction greatly determines the safe and economic wind-resistant design of cladding system in the façade of buildings. This study focuses on two localized regions with severe suction of a building, i.e., the lower windward corner of side wall and the region immediately upstream of trailing edge. The aspect ratio of building is 3. The characteristics and mechanism of wind peak pressures are investigated by standard, spectral and conditional proper orthogonal decomposition (POD). Spectral POD extracts the space–time modes which oscillate at the single frequency of the anti-symmetric vortex shedding, where the pressure distributions have the shape of ‘dragonfly’ wing and opposite signs on two side walls. Conditional POD is demonstrated to be a powerful tool to study the average evolution of peak pressures. By inspection of conditional POD modes, high positive fluctuating pressure is observed in the trailing portion of the lower side wall, accompanied by the minimum pressure in the windward corner. The identified pressure behaviors provide the statistical evidences for flow reattachment and shear-layer roll-up which were observed by instantaneous flow visualization in the literature. The trailing-edge peak pressure in the middle-height region is induced by trailing-edge vortex of great vorticity concentration. The flow mechanism and occurrence phase of trailing-edge peak pressures are similar to those of infinite-length cylinders.

SUPERFICIAL MYOFIBROBLASTOMA OF THE GENITAL TRACT : A CASE REPORT OF VAGINAL SMFGT

Superficial myofibroblastoma of the lower female genital tract is a rare benign, recently recognized neoplasm that mostly affects the vulvovaginal area. In this paper we reported a case of 47years old lady who had 3-Normal vaginal deliveries , she had presented with complain of dysuria , difficult micturition lower abdominal pain, heaviness in the vagina and vaginal discharges. Vaginal examination showed a well demarcated , smooth mass measuring about 7cm x3cm. Transvaginal ultrasound was performed which showed a well -defined isoechoic solid lesion with heterogenous echo pattern which occupied the upper portion of the anterior vaginal wall. Magnetic resonance imaging showed a lesion described as a well defined mass at the level of anterior vaginal wall measuring 3.1APX4.5TVX3.3CC cm. The mass was removed per vaginal route , histopathologically, the tumor was characterized by nodular stromal spindle cell lesion, well defined and partly encapsulated with myxoid degeneration and prominent vascular network. No necrosis is seen .No significant mitotic activity indentified. The findings were consistent with superficail myofibroblastoma. Immunohistochemistry stain was carried out which was positive for CD34, Desmin , Vimentin and weakly positive for ER.

Hemangioma of the External Auditory Canal and Temporal Bone: A Case Report and Comprehensive Literature Review.

Although hemangiomas are common in the head and neck area, they are uncommon in the temporal bone. External auditory canal (EAC) hemangiomas are a relatively uncommon otologic condition. In the English literature, only 29 cases of temporal bone hemangioma have been reported. We also present the case of a 32-year-old male patient who presented with an 8-month history of decreased hearing, tinnitus, and aural fullness on the right side. Otoscopic examination of the right ear revealed a smooth, oval, well-circumscribed, reddish, pulsatile, nontender mass, which was about 1 cm in diameter and occupied two-thirds of the EAC. It was soft in consistency, compressible, and appeared to be arising from the right posterior-superior portion of the bony canal wall; the tympanic membrane seemed to be uninvolved. The patient had mild conductive hearing loss of the right ear with an average air-bone gap of 20 dB; the left side was normal. High-resolution contrast-enhanced computed tomographic scanning of the temporal bone showed well-defined, rounded, homogenously enhancing lesions at the posterior-superior aspect of right EAC measuring 0.7 × 0.8 cm. Angiography was performed and there was evidence of vascular blush in the region of the right EAC. Three blood vessels were identified and embolized. The mass was completely removed by the endaural approach, and a retroauricular skin graft to restore cutaneous integrity was not required. Histopathology indicated a capillary hemangioma without cytological atypia or mitotic activity. There was no recurrence 1 year after the surgery.

Contained rupture of a sinus of Valsalva aneurysm: Is it just a matter of luck?

BackgroundContained rupture of the ascending aorta is a rare condition, but the severity of this complication enforces strict guidelines for its prevention and a prompt diagnosis, once already occurred.Case presentationA 66-year-old man with a history of type 2 diabetes, longstanding aortic valve stenosis and aortic root aneurysm of 47 mm was hospital admitted for elective surgery. A Bentall-De Bono procedure was performed in order to replace the stenotic bicuspid aortic valve and exclude the dilated portion of the aortic wall. Intraoperatively, a discontinuity of the aortic wall, just above the aortic annulus, at the non-coronary sinus of Valsalva was incidentally observed. The aortic wall discontinuity was none other than a contained aortic rupture. The preoperative CT-scan images were afterwards analyzed by the radiologist, in order to identify the contained aortic rupture. Indeed a false aneurysm of the non-coronary sinus of Valsalva of a maximum diameter of 15 mm was detected, thanks to a 3D reconstruction.ConclusionsThe diagnosis of contained aortic rupture is certainly demanding, particularly in absence of signs or symptoms of rupture in a chamber of the heart or in the pericardium. Although this case represents a consensus of experts’ opinion, the recognition of these specific cases in which the risk of dissection, rupture or death is at its highest, would allow to operate at the appropriate time, improving the outcomes.

Une longueur excessive des vis inter-fragmentaires de fixation de la paroi postérieure de l’acetabulum permet de prédire une pénétration intra-articulaire

BackgroundThe fixation of posterior wall acetabular fractures often utilizes interfragmentary screws with varying length. Intricate pelvic anatomy and overhanging greater trochanter make obtaining proper screw trajectory difficult. A large measurement may represent aberrant trajectory and breach of the articular surface. This study aims to identify a preferred maximum screw length that avoids intraarticular penetration. HypothesisWe hypothesized that a screw measured 40mm or longer has a high likelihood of being intra-articular. Patients and MethodsA retrospective review included CT scans of 151 consecutive patients collected at a level-1 trauma center was analyzed by two observers. On axial imaging, a straight line was measured at the largest extraarticular portion of the posterior wall simulating ideal screw placement. Another line was measured tangent to the articular surface simulating longest possible extraarticular screw. Measurements were taken at 2-millimeter increments. ResultsThe intra-class correlation coefficient between both observers was excellent (0.75–1.00) for most recorded values. The maximum mean length for straight line measured (m=32.18mm, SD=3.74) which was smaller than the mean length for tangent line (m=38.44, SD=4.29). Exploratory multivariate logistic regression analyses demonstrated increased height, age, and acetabular version were associated with larger measurements greater than 40mm (p<0.05). DiscussionThis study demonstrates that most acetabular posterior walls cannot accommodate a 40mm lag screw. If the measured drill hole is greater than this length, then careful reconsideration of the screw trajectory is warranted to ensure the screw is not intraarticular. Older and taller patients may be able to accommodate longer screws. Level of EvidenceIII.

Rapidly recurrent recalcitrant Rathke Cleft Cyst: Case report and review of the literature

BackgroundRathke Cleft Cysts (RCC) are cystic sellar or suprasellar nonneoplastic lesions that are thought to originate from remnants of the rathke pouch. Postoperatively, RCCs have a tendency to reaccumulate, after which preoperative symptoms may recur. However, there exists very little evidence on which treatments are most effective in these patients. Case-descriptionIn this report, we present a unique case of a symptomatic RCC that recurred four times after initial transsphenoidal surgery. Following each surgery, the patient had significant visual improvement with post-op imaging displaying decompression of the neural elements. However, RCC reaccumulated in strikingly rapid time intervals of 1.5 months, 0.5 months, 1.5 years, and 5 months after each respective prior surgery. Repeat interventions with transsphenoidal, pterional and supraorbital approaches were unsuccessful in providing a durable treatment response. The patient ultimately underwent radiotherapy after a final surgical marsupialization of the cyst and has since displayed stable imaging with improved vision. This patient represented a ‘perfect storm’ of factors that may contribute to cyst recurrence, including substantial visual field deficits, large cyst size, peripheral wall enhancements on MRI, an intraoperative CSF leak, use of a fat graft, subtotal resection of the portion of cyst wall that adhered to important suprasellar structures, squamous metaplasia noted in cyst wall, and suprasellar extension. ConclusionsWe demonstrate that different surgical approaches through repeat surgeries may not assist in prevention of further recurrence; instead, we propose that radiotherapy should be offered early in the treatment course of recurrent cases that have additional risk factors for further reoccurrence.

Asherman’s Syndrome (Intrauterine Synechiae)

Asherman’s syndrome is a rare, acquired, gynecological disorder of the uterus but there is no clear consensus about management and treatment. It also known as intrauterine synechiae or uterine synechiae. Synechiae means adhesions. It is characterized by the bonding of scar tissue that lines the walls of the uterus, which decreases the volume of the uterine cavity. It can be severe (more than 75% of the front and back walls of the uterus can fuse together) to moderate and mild, where only smaller portions of the uterine wall fuses together. Patients can experience the symptoms depending on the severity of the disease, ie reduced menstrual flow, amenorrhea, increased uterine muscle cramping, abdominal pain and in some case women can develop infertility. The initiation of hysteroscopy has revolutionized its diagnosis and management and also it is considered the most valuable tool in diagnosis and management. The treatment options like hysteroscopic surgery as well as preventive (Foley catheter) and restorative therapies (hormone treatment) and newer option of stem cell treatments are also currently being explored to treat severe cases of Asherman’s syndrome.

Numerical simulation of buoyancy-induced heat transfer and entropy generation in 3D C-shaped cavity filled with CNT–Al2O3/water hybrid nanofluid

Abstract Three-dimensional investigation has been carried out to simulate buoyancy induced heat transfer and fluid flow as well as entropy creation inside C-shaped enclosure charged with based water CNT–Al2O3 (15–85%) hybrid nanofluid. Left side is isothermally heated while the vertical portions of the right wall are isothermally cooled. Effects of various parameters on the flow behavior and the produced irreversibilities, namely the cavity aspect ratio (0.1 ≤ Ar ≤ 0.4), Rayleigh number (103 ≤ Ra ≤ 106) and volumetric fraction of hybrid nanofluid (0 ≤ φ ≤ 0.06) have been examined. It was revealed that the aspect ratio is the main controlling parameter of thermal energy transfer and generated entropy. In addition, for specific Ra, adding hybrid nanoparticles leads to the increase of the average Nusselt number while the highest produced entropy is observed with higher Rayleigh number. Moreover, the maximum Bejan number occurred for a shape factor Ar = 0.1 and Ra = 104 disregarding the hybrid nanoparticles volume fraction showing the dominance of thermal irreversibility over the viscous dissipation irreversibility in such conditions.

The epithelial layers of the body wall in hornerid bryozoans (Stenolaemata: Cyclostomatida).

Bryozoans are small colonial coelomates. They can be conceptualised as “origami‐like” animals, composed of three complexly folded epithelial layers: epidermis of the zooidal/colonial body wall, gut epithelium and coelothelium. We investigated the general microanatomy and ultrastructure of the hornerid (Cyclostomatatida) body wall and polypide in four taxa, including three species of Hornera and one species belonging to an undescribed genus. We describe epithelia and their associated structures (e.g., ECM, cuticle) across all portions of the hornerid body wall, including the terminal membrane, vestibular wall, atrial sphincter, membranous sac and polypide–skeletal attachments. The classic coelomate body wall composition (epidermis–ECM–coelothelium) is only present in an unmodified form in the tentacle sheath. Deeper within a zooid it is retained exclusively in the attachment zones of the membranous sac: [skeleton]–tendon cell–ECM–coelothelium. A typical invertebrate pattern of epithelial organisation is a single, continuous sheet of polarised cells, connected by belt desmosomes and septate junctions, and resting on a collagenous extracellular matrix. Although previous studies demonstrated that polypide‐specific epithelia of Horneridae follow this model, here we show that the body wall may show significant deviations. Cell layers can lose the basement membrane and/or continuity of cell cover and cell contacts. Moreover, in portions of the body wall, the cell layer appears to be missing altogether; the zooidal orifice is covered by a thin naked cuticle largely devoid of underlying cells. Since epithelium is a two‐way barrier against entry and loss of materials, it is unclear how hornerids avoid substance loss, while maintaining intracolonial metabolite transport with imperfect, sometimes incomplete, cell layers along large portions of their outer body surface.

Excessively long interfragmentary screws for posterior wall acetabular fractures can predict intra-articular penetration

BackgroundThe fixation of posterior wall acetabular fractures often utilizes interfragmentary screws with varying length. Intricate pelvic anatomy and overhanging greater trochanter make obtaining proper screw trajectory difficult. A large measurement may represent aberrant trajectory and breach of the articular surface. This study aims to identify a preferred maximum screw length that avoids intra-articular penetration. HypothesisWe hypothesized that a screw measured 40 millimeters or longer has a high likelihood of being intra-articular. Patients and MethodsA retrospective review included CT scans of 151 consecutive patients collected at a level-1 trauma center was analyzed by two observers. On axial imaging, a straight line was measured at the largest extraarticular portion of the posterior wall simulating ideal screw placement. Another line was measured tangent to the articular surface simulating longest possible extraarticular screw. Measurements were taken at 2-millimeter increments. ResultsThe intra-class correlation coefficient between both observers was excellent (0.75–1.00) for most recorded values. The maximum mean length for straight line measured (m=32.18mm, SD=3.74) which was smaller than the mean length for tangent line (m=38.44, SD=4.29). Exploratory multivariate logistic regression analyses demonstrated increased height, age, and acetabular version were associated with larger measurements greater than 40mm (p<0.05). DiscussionThis study demonstrates that most acetabular posterior walls cannot accommodate a 40 millimeter lag screw. If the measured drill hole is greater than this length, then careful reconsideration of the screw trajectory is warranted to ensure the screw is not intra-articular. Older and taller patients may be able to accommodate longer screws. Level of EvidenceIII.

Cucurbiturils mimicked by low polarizability solvents with pre-formed cavities: an empirical model to predict hydrocarbon selectivity.

Relative binding affinities of a series of nine rigid hydrocarbons towards the cavity formed by a portion of the inner wall of cucurbit[8]uril (CB[8]) and a positive auxiliary guest were determined by competitive 19F NMR titrations in deuterium oxide. The corresponding free binding energies were corrected by the hydrocarbon computed solvation energies to obtain their free energies of transfer from the gas phase to the CB[8]/auxiliary guest cavity. These energies correlate linearly with the hydrocarbon static polarizabilities, thereby suggesting that the selectivity is driven, perhaps exclusively, by dispersive interactions between the hydrocarbons and the tailor-made cavity, regardless of the degree of unsaturation of the guests. The free energies of transfer also correlate linearly with the energy released upon introduction of the hydrocarbon into a pre-formed cavity extruded from a solvent (benzene) selected to mimic the polarity and polarizability of the CB[8]/auxiliary probe cavity – and this, with a unity slope. Among other features, this empirical model also accurately predicts the relative binding affinities of various rigid hydrocarbons to CB[6] and CB[7], as well as noble gases to CB[5], when the macrocycles are mimicked with pre-formed cavities in perfluorohexane or perfluorohexane/benzene mixtures, both being notoriously non-polar and non-polarizable environments.

Topographically Controlled Marangoni-Rayleigh-Bénard Convection in Liquid Metals

Convection induced in a layer of liquid with a top free surface by a distribution of heating elements at the bottom can be seen as a variant of standard Marangoni–Rayleigh–Bénard Convection where in place of a flat boundary at constant temperature delimiting the system from below, the underlying thermal inhomogeneity reflects the existence of a topography. In the present work, this problem is investigated numerically through solution of the governing equations for mass, momentum and energy in their complete, three-dimensional time-dependent and non-linear form. Emphasis is given to a class of liquids for which thermal diffusion is expected to dominate over viscous effects (liquid metals). Fixing the Rayleigh and Marangoni number to 104 and 5 × 103, respectively, the sensitivity of the problem to the geometrical, kinematic and thermal boundary conditions is investigated parametrically by changing: the number and spacing of heating elements, their vertical extension, the nature of the lateral boundary (solid walls or periodic boundary) and the thermal behavior of the portions of bottom wall between adjoining elements (assumed to be either adiabatic or at the same temperature of the hot blocks). It is shown that, like the parent phenomena, this type of thermal flow is extremely sensitive to the specific conditions considered. The topography can be used to exert a control on the emerging flow in terms of temporal response and patterning behavior.

593 Spontaneous coronary artery dissection in young

Abstract Aims We present the case of a 25 years-old patient, presented to the Emergency Department for chest pain and epigastralgia complicated by vomiting. Symptoms started about 30 h before, afterwards an effort. The patient did not have any known cardiovascular risk factors (except for sporadic consumption of cannabis) and family medical history was negative for premature cardiovascular disease or sudden cardiac death. His past medical history was unremarkable. Methods and results Clinical examination was normal. ECG was suggestive for subacute anterior ST-elevation myocardial infarction (QS in V1–V4 leads with ST segment elevation and biphasic T-waves in V4–V6) and was accompanied by significant elevation of myocardial necrosis biomarkers (hsTnT 3416 ng/l, n.v. &amp;lt;15). Echocardiography revealed a severely reduced left ventricular ejection fraction (LVEF = 30%) with regional wall motion abnormalities (apical and septal akinesia, and anterior mid-ventricular segment hypokinesia). Coronary angiography was suggestive for a dissection of the proximal-to-mid left anterior descending artery. Dissection flap, subocclusion of the first septal branch, and intramural thrombosis were noted. Direct stenting with drug-eluting stent was successful, with thrombolysis in myocardial infarction (TIMI) flow grade 3. The patient was started on dual antiplatelet treatment (aspirin and ticagrelor), ACE-inhibitors, beta blockers, and spironolactone. Further testing ruled out other conditions that may be associated with spontaneous coronary artery dissection (autoimmune diseases, including vasculitis, connective tissue disease, coagulative disorders). The clinical course was complicated by pericarditis and the development of LV apical thrombus. So, patient was started on anticoagulation (warfarin) with subsequently downgrading from ticagrelor to clopidogrel. Echocardiographic follow-up documented a progressive improvement of LVEF (50%), and global longitudinal strain (GLS −15%) with persistence of wall motion abnormalities in the apical and septal segments. Partial resolution of intracavitary thrombi was documented. CMR revealed LV apical aneurysm. Moreover, the use of dedicated sequences showed transmural late gadolinium enhancement in akinetic segments, and fatty metaplasia of the apical portion of the anterior wall and anterior septal wall. Finally, early gadolinium enhancement imaging, confirmed the persistence of LV stratified apical thrombus. Conclusions Spontaneous coronary artery dissection (SCAD) is an underdiagnosed and frequent cause of acute coronary syndrome (ACS) in young-to-middle aged patients, particularly women; therefore, even in young people, a chest pain episode suggestive for an ischaemic cause should never be underestimated. Cardiac magnetic resonance is the most accurate method to evaluate the sequelae of myocardial infarction (including LV size and function, presence of fatty metaplasia, extent and transmurality of ischaemic scar, presence of thrombi), to aid in differential diagnosis and to define prognosis and guide the therapeutic management.