Academic literature on the topic 'Annular lichen planus'

Abstract This chapter on dermatopathology offers an exploration of the pathology of common and important skin conditions. Common inflammatory skin conditions like eczema, psoriasis, lichen planus, erythema multiforme, granuloma annulare, acne, rosacea and urticaria are covered, elucidating their clinical and pathological findings. Autoimmune blistering disorders such as pemphigus vulgaris, dermatitis herpetiformis, bullous pemphigoid are examined, detailing their immunopathogenesis, clinical features, histopathological and immunofluorescence findings. The chapter encompasses benign epidermal, melanocytic, soft tissue, and adnexal tumours, providing insights into their histopathology. It then delves into common skin cancers like basal cell carcinoma, squamous cell carcinoma and malignant melanoma emphasizing their risk factors, presentation and histopathology. Furthermore, some rare skin malignancies like Merkel cell carcinoma, mycosis fungoides, dermatofibrosarcoma protuberans, and atypical fibroxanthoma are analyzed, highlighting key pathological findings.

Plants and animals require water, energy sources, and nutrients to make tissues and perform vital functions. The primary source of energy is the sun. Green plants use solar energy to manufacture organic compounds that are later oxidized to produce energy for both plants and animals. Many microorganisms produce energy by inorganic chemical reactions, but that source of energy is minor compared to the very large amounts of solar energy used by green plants. The major source of water and nutrients (other than CO2) for green plants is soil. Barren rocks, including ultramafic rock outcrop and talus, are colonized by lichens, which are symbiotic alliances of fungi and either cyanobacteria or green algae. These and other small organisms promote weathering and contribute to soil formation. Once soils are deep enough to support vascular plants (plants with roots), plants are the primary users of soils and producers of ecosystem biomass. Vascular plants send roots into soils and exploit both a high soil particle surface area and soil solutions, neither of which are available to lichens growing on rock surfaces. The surface area of particles in a soil 10 cm deep is about a thousand times greater than a planar bedrock surface if the soil is coarse sand, or about a billion times greater if the soil is clayey. With these dramatic increases in surface area accompanying soil formation, and lack of water retained on rock surfaces, it is easy to understand that ecosystem productivity is relatively low on rock surfaces and increases greatly with soil depth in very shallow soils. Annual plants approach maximum productivity in moderately deep soils and trees in deep or very deep soils. Ecosystems with serpentine soils are generally less productive than ecosystems with other kinds of soils, and they have unique plant species distributions. Therefore, serpentine soils attract attention from botanists who are interested in the profound effects that serpentine soils have on plant distributions and growth. These effects include those that affect the supply of water (section 8.1) and those that affect the supply of nutrients (section 8.2) to plants. These in turn affect plant growth and productivity (section 8.3).

In coastal dune systems, plant communities are fundamentally the product of interaction between disturbance of the substrate, impact of high wind velocities, salt spray episodes, sand accretion levels and other factors of the environmental complex. Burial by sand is probably the most important physical stress that alters species diversity by eliminating disturbance-prone species (Maun 1998). There is a close correlation between sand movement and species composition, coverage and density (Moreno-Casasola 1986; Perumal 1994; Martínez et al. 2001). Sand accretion kills intolerant species, reduces the relative abundance of less tolerant species and increases the abundance of tolerant species. It filters out species as the level of burial starts to exceed their levels of tolerance. For example, lichens and mosses are the first to be eliminated, then the annuals and biennials and finally the herbaceous and woody perennials. Again within each life form and genus there are significant differences in survivability. Burial imposes a strong stress on production by altering normal growth conditions and exposing plants to extreme physiological limits of tolerance. Do plant communities occurring in different locations within a dune system correspond to the amount of sand deposition? Several studies (Birse et al. 1957; Moreno- Casasola 1986; Perumal 1994) show that the species composition and their distribution are strongly related to the long-term average sand deposition. The evolution of a plant community in coastal foredunes requires frequent and persistent predictable burial events specific to a particular coast. In a large majority of sea coasts burial occurrences are of relatively low magnitude and species occupying the coasts are well adapted to withstand the stress imposed by burial. This recurring event within the generation times of plant species allows them to acquire genes of resistance over time and evolution of adaptations to live in this habitat. A prerequisite to survive in this habitat happens to be the ability to withstand partial inundation by sand. To survive the dynamic substrate movement a plant species must be a perennial, be able to withstand burial, endure xerophytic environment, spread radially and vertically, and adapt to exposure on deflation and coverage on burial (Cowles 1899).

Back pain is a common chief complaint in the emergency department. With the differential ranging from musculoskeletal pain to cauda equina, there are a plethora of diagnoses. Differentiating between benign back pain and back pain that warrants further evaluation and even possible emergent surgical intervention is often a challenge in the acute setting. In this case report, a strange combination of all new symptoms including lichen planus, fevers, chills and atraumatic back pain lead to the eerie and very unexpected diagnosis of a peri-aortic abscess.

Introduction: Chronic vulval symptoms are common complaints in women seeking health care and can significantly interfere with a woman’s sexual function and sense of well being. Many practitioners feel diagnostically challenged, particularly by chronic or recurrent forms of vulval disease. The aim of this study was to assess the role of various diagnostic modalities in evaluation of chronic vulval symptoms. Methods: Between August 2012 and February 2014, 100 women presenting with chronic vulval symptoms (i.e. ≥ 3 months duration) were evaluated. All of them had a thorough clinical history taken including use of vulval washes and creams, a general and gynaecological examination. Patients having chronic vaginal discharge in addition had urethral, vaginal and cervical smear and culture. All women had a careful examination of the vulva with and without magnification. Vulval scrape cytology was taken after moistening the vulva with normal saline and stained by Pap stain. Colposcopy of the vulva was then carried out after applying 5% acetic acid and 1% toluidine blue dye. Vulval biopsy was taken from suspicious areas on colposcopy and further management was based on histopathology report. Results: The mean age of women in our study was 43.57 years (range 22-80 years.), 70% women were pre-menopausal and 30% were post-menopausal. The mean duration of symptoms was 1.625 years (range 6 months - 15 years) and atypical vulval hygiene practices (excessive washing with soaps) was used in 77% of women. The commonest presenting complaint was pruritus in 92% of women; visible lesions on vulva were seen in 20%, pain in 6% and burning sensation in vulva in 5% of women. The histopathology was abnormal in 77 patients; the most common histopathological finding was non-neoplastic epithelial disorders in 64 women {Squamous cell hyperplasia (n=52), Lichen Sclerosus et atrophicus (n=6), other dermatoses including lichen Planus (n=6)}. Vulvar Intra-epithelial Neoplasia (VIN) was seen in 6 patients, 5 were squamous type VIN and 1 was non-squamous type (Paget’s disease). Squamous cell carcinoma was seen in 3 patients; malignant melanoma, benign appendiceal tumor, angiofibroma and neurofibroma in 1 patient. Examination without magnification had sensitivity of 25.97% and with magnification was 29.87% and specificity was 100% for both of them. Cytology had sensitivity and specificity of 75.32% and 86.95% respectively and sensitivity and specificity of colposcopy was 77.92% and 17.39% respectively. Conclusion: Clinical examination with and without magnification had low sensitivity but were highly specific in diagnosing vulvar lesions. A normal vulval smear and colposcopy have a high negative predictive value and are very reassuring. Colposcopy and biopsy is the gold standard for diagnosis, however clinical examination with naked eyes and magnifying glass are invaluable and can diagnose most of the neoplastic lesions.

Appropriate consideration of tolerances is critical to the design and manufacture of products that meet customer requirements and defined cost targets. Tolerance analysis is most commonly conducted at the individual part or sub-assembly level utilizing basic stack-up methods (worst-case analysis) to ensure the producibility of the assembled product. A worst-case analysis assumes that each dimension in the stack-up will be manufactured on the extreme end or limit of its assigned tolerance (max or min) in such a way that all tolerances become additive. This usually results in tighter than required drawing tolerances being assigned to guarantee the product can be assembled. Modern day manufacturing processes focus on targeting the nominal dimensional value, so it is safe to assume that a higher number of parts will be produced closer to the nominal value than parts produced at the extreme end of the tolerance range. When evaluating the tolerance stack-up of a larger assembly with many parts additional tolerance analysis methods apply (Root Sum Squared, RSS), and a worst-case analysis becomes more costly and less meaningful. The RSS method of tolerance analysis takes into consideration manufacturing targets and applies normal distribution methods to assess more likely tolerance results, allowing relaxed drawing tolerances to be assigned while still maintaining a high level of confidence in a successful assembly. For analysis of complex systems or installations, tolerance studies using more sophisticated approaches to deal with variation such as Monte Carlo statistical analysis is required. Variational Tolerance Analysis (VTA) tools available today allow a typical Monte Carlo tolerance simulation to be visualized by the designer through 3-dimensional real time manufacturing simulations and sensitivity analysis. This in turn simplifies the development process and allows better identification of tolerance drivers within a large system installation; analysis of the geometric effect of tolerances within the installation; and the ability to quickly iterate the analysis to optimize designs for producibility and lower cost. In this paper, the use of VTA is assessed and quantified to form a business case for further investment by Lockheed Martin. In the course of this work, VTA has been evaluated both before and after final designs were released to manufacturing. Before final designs are released VTA can be used for design optimization (i.e. build before you build simulations), part sequencing studies, or to gain insight into the assembly/installation process enabling advanced planning to take place up front. VTA can also address challenges discovered after final designs have been released to manufacturing and parts are on hand (i.e. during the build) such as: assembly issues, out of spec part disposition, and to inform manufacturing of any special tooling or part rework considerations aiding in corrective action or risk mitigation plans. Cost savings to the business due to the implementation of VTA has been demonstrated in 4 distinct ways: 1.Reduced design revisions – Design optimization up front reduces future revisions caused by producibility and tolerance related discoveries. 2.Manufacturing – Through tolerance optimization, nonimpactful tolerances can be relaxed while still ensuring a successful assembly. 3.Reduced build schedule – Increased assembly awareness and advanced planning allows a streamlined production process with risk mitigation strategies in place. 4.Reduced scrap, rework, repair (SRR) – Engineering labor to disposition out of spec parts is reduced by entering as-measured tolerances into the simulation model to assess the overall impact to installation success. The conclusion is VTA simulations provide measurable benefits to the business through robust design optimization, and multi-layered cost and risk reductions.