Unilateral hyperpigmented lesion of the breast

Muco‐cutaneous melanosis is a benign entity with no progression. Although, dermoscopic features may help to differentiate melanosis from malignant pigmented diseases, histopathology remains crucial for the confirming of melanosis of the nipple and areola. Herein, we represent a new case of melanosis of the areola and we describe its clinico‐pathological aspects.

Muco‐cutaneous melanosis is a benign entity with no progression. Although, dermoscopic features may help to differentiate melanosis from malignant pigmented diseases, histopathology remains crucial for the confirming of melanosis of the nipple and areola. Herein, we represent a new case of melanosis of the areola and we describe its clinico‐pathological aspects.

Lichen planus pigmentosus post COVID-19-vaccination: A case report with literature review

Lichen planus (LP) is a T cell‐mediated chronic inflammatory disorder. Several clinical variants based on lesion morphology and localization are reported. LPP remains uncommon with an unknown etiology. Besides, some precipitating factors have been suggested in the literature including hepatitis C infection; restrictive underwear, localized friction, and sun exposure.^{(1, 2)} Herein, we present a case of new‐onset of LPP following the ChAdOx1 nCoV‐19 (Oxford‐AstraZeneca) vaccine. A literature review was also conducted to summarize the various cases of LP induced and/or trigged by Covid‐19 vaccine.

Multiple asymptomatic papules following breast cancer treatment

Acquired lymphangiectasia (AL) represents superficial lymphatic dilatation caused by different processes. It is a consequence of lymphatic damage by an external cause; leading to obstruction of local lymphatic drainage.1 We report a case of AL of the breast in a 45‐year‐old woman mimicking warts.

Kaposiform hemangioendothelioma with fatal income: Kasabach–Merritt phenomenon and hypercalcemia

Kaposiform hemangioendothelioma is a rare, borderline tumor that typically occurs during early childhood. Kasabach–Merritt phenomenon is a complication characterized by a consumptive coagulopathy resulting from the localized intravascular coagulation. Hypercalcemia generation is a rare association that was related in our case to parathyroid hormone‐related protein produced by this angioma.

A comparative study of oxidant-antioxidant status in stable and active vitiligo patients

The pathogenetic mechanisms in vitiligo have not been completely clarified. One of the major hypotheses in the pathogenesis of vitiligo is the oxidative stress hypothesis. The active or stable phase of vitiligo is defined on the basis of the progression or appearance of new lesions in the last 3 months and the absence of new lesions or their progression in the last 6 months, respectively. Eighteen patients with active vitiligo, 18 patients with stable vitiligo, and 40 controls were included in this study. We examined serum levels of malondialdehyde, selenium, vitamin E and A, and the erythrocyte activities of glutathione peroxidase, superoxide dismutase, and catalase. Our results revealed a significantly higher level of serum malondialdehyde, selenium in patients with active disease compared with the controls. Significant higher increase in erythrocytes superoxide dismutase activities was observed in active vitiligo group, erythrocyte glutathione peroxidase activity was decreased significantly in active disease, whereas erythrocyte catalase activity and plasma vitamin E and A levels were not different in vitiligo patients as compared with controls. Our study shows that oxidative stress is involved in the pathophysiology of both active and stable vitiligo but increased imbalance of antioxidants was observed in the blood of active vitiligo patients.

Investigations on Capillary and Viscous Displacement Under Ultrasonic Waves

Abstract

In this paper, the influence of ultrasonic waves on capillary and viscous displacement of oil in porous media was investigated. Capillary (spontaneous) imbibition experiments were conducted using various fluid pairs such as air-water, mineral oil-brine, mineral oil-surfactant solution, kerosene-surfactant solution, and mineral oil-polymer solution. Berea sandstone and Indiana limestone cores were used as the matrix. Oil saturated cores were immersed into the aqueous phase and subjected to high intensity ultrasound from a specially designed ultrasonic chamber. The resulting recovery was recorded against time, and compared to a control experiment without ultrasound. A substantial increase in ultimate recovery was observed for most of the fluid pairs, with some improvements in recovery rate.

To further investigate whether ultrasound induces a perturbation at the liquid-liquid interface of immiscible fluids, a series of Hele-Shaw type experiments were run. The resulting fingering pattern was strongly dependent on the interfacial tension of the fluid pair, and the injection rate. Ultrasound stabilized the fluid-fluid front of high interfacial tension fluid pairs, but generated larger instabilities when interfacial tension was low.

Introduction

For the past four decades, researchers have explored the use of acoustic energy to improve oil recovery that could potentially be an economic and environmentally-friendly alternative to current IOR methods. Beresnev and Johnson(1) provide an extensive review of the major developments of acoustic stimulation and its limitations. Guo et al.(2) discuss recent field results of seismic stimulation in China.

Despite numerous promising field trials and patents, the exact mechanism behind ultrasonic stimulations is poorly understood. Most of the findings have been speculative with little experimental verification. The reason is two-fold. Firstly, the problem is very complex, involving a superposition of several different mechanisms. Secondly, it is not certain how far an acoustic wave propagates into the reservoir, or how such propagation occurs. Ultrasonic applications are limited to the near-wellbore area due to the high attenuation through the rock or fluids. As a consequence, most research in recent years has shifted to low energy, low frequency waves that can propagate several kilometres into the reservoir. However, because low frequency waves disperse into high-frequency harmonics as they travel through a porous medium, one would still expect ultrasonic waves to be present in the reservoir. An analytical treatment of compression and shear wave propagation in saturated porous media was first developed in two classic papers by Biot.(3, 4)

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Acoustic waves are usually applied in three ways: pressure pulsing, down-hole vibration, and surface vibration. Applications range from enhanced oil recovery (EOR) to well stimulation, in situ upgrading, wellbore cleaning, and soil remediation.

Acoustic stimulation is believed to positively contribute to the flow of oil in porous media by:Increasing the relative permeability of the phases;Reducing the adherence of wetting films onto the rock matrix, due to non-linear acoustic effects such as in-pore turbulence, acoustic streaming, cavitation, and perturbation in local pressures(5);Reducing surface tension, density, and viscosity as a consequence of heating by ultrasonic radiation(6);Altering of rheological properties of non-Newtonian fluids;