•Hydatid cyst results when humans get infected by ingesting the eggs of Echinococcus Granuloses. The oncospheres penetrate the intestinal wall and migrate to various organs. They develop into hydatid cyst and gradually is filled with daughter cysts.•We present a 69-year-old female, a native of Uzbekistan, who presented with vague right upper quadrant pain. Radiologically 20 cm liver cyst and multiple pelvic cysts with a stage of CE2 (Fig. A). Serology for Echinococcal antibody was positive.•After 2 months of Albendazole, she underwent Laparoscopic puncture aspiration and injection with 20% saline (PAIR) and peri-cystectomy of the pelvic cysts. After uneventful recovery and further Albendazole, she underwent a Robotic-assisted PAIR and partial peri-cystectomy of the liver cyst with the repair of the duct to cyst communication. (Fig. F, G, H, I). She did need a post-operative ERCP with Sphincterotomy and then was asymptomatic 2 weeks after. Her Serology tuned intermediate 2 months later.•Pathology:1.Cytology: Aspirate: Scattered scolices, inflammatory cells, and abundant amorphous debris consistent with hydatid cyst (Fig. B)2.Gross: Bilateral 5-cm pelvic cysts with pale yellow, soft to firm walled, multiple cavities (Fig. C)3.Microscopy - Fibrofatty outermost layer and a two-layered cyst wall including a thin germinal epithelium covered by a thick acellular outer membrane (Fig. D), Multiple parasites, some eosinophilic (Fig. E)4.Liver cyst - daughter cysts of Echinococcus and brood capsule with protoscolices (Fig. H)•Our case highlights the role of correlating various modalities in the diagnosis of hydatid disease.

The aerodynamic performance of oscillating piezoelectric fans has been the focus of many research studies due to their potential as active cooling mechanisms for thermal management applications. These studies have typically focused on commercially available fans with flexible beams that are made to oscillate by tuning the alternating input voltages to the beam’s resonant frequency. Geometric variables such as fan height and length have previously been investigated; however, fan thickness has remained a fixed geometric constraint ($${\mathcal {O}}\sim 0.1$$ mm) to allow feasible resonant frequencies to be achieved. This study investigates the influence of beam thickness on the flow field generated by an oscillating beam. The beam in this study is a rigid cantilever that is mechanically oscillated at a fixed amplitude and frequency thereby obviating the requirement to operate at resonance. Thicknesses of 1 and 3.7 mm are considered. A custom-designed particle-image velocity (PIV) facility was used to capture the induced phase-locked and time-averaged flow fields in two planes. The beams were noted to produce markedly different wakes within the oscillation plane. The 1-mm beam induced two distinct diverging jets—consistent with much of the literature on piezoelectric fans. In comparison, the 3.7-mm beam created two strong lateral wake regions with minimal fluid disturbance downstream of the beam tip. Out-of-plane measurements, as well as numerical models, revealed that fluid separation from the 3.7-mm beam is inhibited due to the more dominant influence of viscous friction on the larger, upper and lower surfaces of the rigid structure. The numerical analysis also revealed the significant influence of shed, counter-rotating vortex pairs on the pressure fields around the beam structures during the subsequent half-stroke. The results of this work may inform the design of oscillating fans for use in thermal management applications, as well as contribute to the literature on the complex phenomenon of flapping wing flight.

An acoustic levitator uses an array of ultrasonic transducers to generate a standing acoustic pressure field which exerts a radiation force on small particles, allowing the particles to be trapped, relocated, separated or combined. Experiments on levitating particles of different densities and calculations of the acoustic radiation force and moment have been reported in the literature. However, direct inspection on the acoustic pressure field pattern is seldom carried out. This paper reports an investigation on the performance of an existing acoustic levitator design, which uses off-the-shelf components, by comparing the visualized pressure field from Schlieren imaging to analytical simulations. The ability to compare Schlieren imaging results to analytical simulations readily can prove to be a vital tool. Since the simulations provide an ideal pressure field, the imaging of the levitator pressure field can highlight discrepancies between the real and ideal cases. This can be especially useful as a diagnostic tool to identify the cause of a drop in performance of the acoustic levitator in a real world scenario.

Casestudy: Hydatid cyst results when humans get infected by ingesting the eggs of Echinococcus Granulosus. Upon release, the six-hooked oncospheres penetrate the intestinal wall and migrate via circulation to various organs, mostly liver and lung. Here, they develop into hydatid cyst. The cyst enlarges gradually and is filled with daughter cysts and protoscolices. We report the case of a 69-year old female, native of Uzbekistan, who presented with right upper quadrant pain. Imaging showed a 20 cm liver cyst and multiple pelvic cysts with a stage of CE2 implying that they were most likely functional. Serum Echinococcal antibody was positive. After 2 months of Albendazole treatment, there was no radiological change. The patient underwent laparoscopic puncture aspiration and injection with 20% saline (PAIR) and pericystectomy of the pelvic cysts. The aspirate revealed scattered scolices, inflammatory cells and abundant amorphous debris consistent with hydatid cyst. Bilateral 5-cm pelvic cysts had pale yellow, soft to firm walled, multiple cavities. Microscopy revealed a fibrofatty outermost layer with chronic inflammation and a two-layered cyst wall including a thin germinal epithelium covered by a thick acellular outer membrane. Multiple parasites, some degenerate (dense eosinophilic) were present, confirming the cytologic diagnosis of cystic echinococcosis. Following further treatment with Albendazole, she underwent a robotic assisted PAIR and partial peri-cystectomy of the liver cyst with repair of the duct to cyst communication. The liver cyst contained daughter cysts of Echinococcus and brood capsule with protoscolices. After 2 months more of Albendazole her Elisa was intermediate. A prior study reported cytopathologic diagnosis of hydatid cyst in 17 patients evaluated for various masses. Our case highlights the role of cytology sampling in confirming the diagnosis of hydatid disease. Potentially fatal in untreated patients, this entity has to be considered in the differential diagnosis of cystic lesions.

Casestudy: Chordoma is an uncommon primary malignant tumor of the bone showing notochordal differentiation. The current World Health Organization classifies chordoma into three subtypes: conventional, chondroid, and dedifferentiated. Poorly differentiated chordoma (PDC) is a newly described variant of chordoma, with its own distinct features in terms of age distribution (common in pediatric and young adults), histopathology (lack of physaliphorous cells and chondromyxoid matrix), immunohistochemical and molecular characteristics (loss of SMARCB1/INI1 expression) and clinical outcome (poor prognosis with rapid onset of local recurrence and metastasis). Herein, we report the case of a 43 year old man with history of fall and injury of tailbone 2 years prior, who presented with pain and swelling at the sacrcoccygeal region and intermittent numbness in the legs. MRI of the pelvis showed a 9.8 cm lobulated mass centered on the sacrum with osseous destruction of S5 through coccyx, with intralesional hemorrhage, and mild heterogeneous enhancement. Biopsy of the sacrococcygeal mass demonstrated a malignant neoplasm composed of lobules of epithelioid cells with abundant eosinophilic cytoplasm showing focal vacuolization, and mild to moderate nuclear pleomorphism with an average 3 mitoses per high power field (400x). Immunohistochemically, the neoplastic cells were positive for pancytokeratin, CAM 5.2, vimentin and brachyury. They had loss of SMARCB1 (INI1) and were negative for S100, CK7, CK20, desmin and actin. The location, imaging studies, morphologic features and immunohistochemical profile were consistent with poorly differentiated chordoma with rhabdoid features. With its specific clinical, morphologic, immunophenotypical, and molecular features, PDC may be recognized as a chordoma subtype in a future WHO classification. According to current knowledge, the diagnosis of PDC should be restricted to cases with brachyury expression (specific for notochord tumors) and INI1 protein loss, especially in tumors of pediatric and young patients, regardless of cellular characteristics.

Piezoelectric fans have been studied extensively and are seen as a promising technology for thermal management due to their ability to provide quiet, reliable cooling with low power consumption. The fluid mechanics associated with a piezoelectric fan are similar to that for a flapping bird wing, which are known to be complex. This paper is the first to investigate the three-dimensional fluid mechanics of an unconfined fan operating in its first vibration frequency mode. A custom built experimental facility was developed to capture the fan's flow field using two-dimensional phase locked Particle Image Velocimetry (PIV). The fluid-structure interaction was also captured through unique two-way coupled three-dimensional simulations of an oscillating beam in which the beam is actuated by a shear force at its resonant frequency and interacts with the surrounding air. This forgoes the need for temporal beam displacement data from experiments as in previous studies, allowing the numerical technique to be used independently. A finite element method is used for the simulations which allows the two-way coupling while maintaining computational efficiency. A three dimensional λ2 criterion constructed from interpolated PIV measurements as well as numerical data was used to identify a horse shoe vortex in the vicinity of the fan and its evolution into a hairpin vortex before it breaks up due to a combination of vortex shedding and flow along the fan blade. The experimental and numerical data are comparatively in agreement, confirming that the methods presented are valid for capturing the complex flow fields generated by this fluid-structure interaction. The results provide both a fundamental understanding on the formation and break-up of vortices from an oscillating beam, and demonstrate a validated approach which can be applied in the development of high efficiency piezoelectrically driven air moving devices and extended to the study of flapping bird and UAV wings.

The flow of shear-thinning viscoelastic fluids is investigated experimentally in a serpentine microchannel at very large Weissenberg numbers (Wi > 104) undergoing elastic instability. The effects of geometric curvature on local flow instability and the consequent heat transfer enhancement are reported. Unlike previous studies where fluids with large zero-shear viscosities (up to 300 mPa.s) were used, we employ a working fluid with a lower viscosity (η0 = 9 mPa.s) more suited to microfluidic heat transfer applications while exhibiting viscoelastic characteristics. This results in Elasticity number (EI = Wi/Re) flows an order of magnitude larger than previously reported in the literature with apparent viscosities close to the solvent viscosity under flow conditions. Detailed Micro Particle Image Velocimetry (μPIV) measurements reveal the local enhancements due to instantaneous flow structures which result in vigorous local mixing at sub-critical Reynolds numbers. In addition the pressure drop increase is moderate as mixing occurs locally and the flow is maintained undisturbed elsewhere throughout the flow path.

Detailed measurements of the flow instability of dilute shear-thinning viscoelastic aqueous solutions, with relatively low zero-shear viscosities, in an obstructed microchannel flow are reported. We examine the flow behaviour resulting from a 100 μm post placed in the channel centreline over a range of Reynolds numbers (\(5<Re<300\)) and Weissenberg numbers (\(20<Wi<10^3\)). Micro-particle image velocimetry measurements show the onset of an upstream instability within a Reynolds number range and at a critical elasticity number corresponding to polymer concentrations above 25 ppm of long-chain polyacrylamide. The instability results in significant local fluctuations in the flow field approaching 30 % of the mean velocity. The magnitude of the local viscosity ratio in the region upstream of the post is proposed as a driving mechanism for the instability which resembles a buckling flow. Additionally, the classical instability owing to separation and vortex formation downstream of the post in Newtonian flow is suppressed and a very long stable wake is observed extending over 10 post-diameters downstream.

The influence of viscoelasticity on bypass transition to turbulence in channel flow is studied using data from direct numerical simulations by Agarwal et al. (2014) 1. The initial field is a superposition of a laminar base state and a localized disturbance. Relative to the Newtonian conditions, the polymeric FENE-P flow delays the onset of transition and extends its duration. The former effect is due to a weakening of the pre-transitional disturbance field, while the prolonged transition region is due to a slower spreading rate of the turbulent spots. Once turbulence occupies the full channel, a comparison of the turbulence fields shows that energetic flow structures are longer and wider in the polymeric flow. The final turbulent state is compared to elasto-inertial turbulence (EIT), where the polymer conformation field takes the form of elongated sheets with wide spanwise extent.

Abstract The evolution of an initially localized disturbance in polymeric channel flow is investigated, with the FENE-P model used to characterize the viscoelastic behaviour of the flow. In the linear growth regime, the flow response is stabilized by viscoelasticity, and the maximum attainable disturbance-energy amplification is reduced with increasing polymer concentration. The reduction in the energy growth rate is attributed to the polymer work, which plays a dual role. First, a spanwise polymer-work term develops, and is explained by the tilting action of the wall-normal vorticity on the mean streamwise conformation tensor. This resistive term weakens the spanwise velocity perturbation thus reducing the energy of the localized disturbance. The second action of the polymer is analogous, with a wall-normal polymer work term that weakens the vertical velocity perturbation. Its indirect effect on energy growth is substantial since it reduces the production of Reynolds shear stress and in turn of the streamwise velocity perturbation, or streaks. During the early stages of nonlinear growth, the dominant effect of the polymer is to suppress the large-scale streaky structures which are strongly amplified in Newtonian flows. As a result, the process of transition to turbulence is prolonged and, after transition, a drag-reduced turbulent state is attained.