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Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
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Control of Leucostoma Canker is possible through a combination of pest and crop management techniques following life cycles of the trees. The strategy is implemented following techniques aimed at reducing number of pathogenic inoculum, minimizing dead or injured tissues to prevent infection, and improving tree health to improve rapid wound healing. Chemical controls have not been very effective at controlling this disease with no fungicides registered specifically for control of "Leucostoma" spp., and demethylation-inhibiting (DMI) fungicides having almost no effect on "L. persoonii".
Thousand cankers disease can be spread by moving infected black walnut wood. Trees intended for shipment should be inspected for dieback and cankers and galleries after harvest. G. morbidia or the walnut twig beetle ("Pityophthorus juglandis") are not currently known to be moved with walnut seed . There is currently no chemical therapy or prevention available for the disease making it difficult to control the spread of the disease from the west to the eastern united states. Wood from infected trees can still be used for commercial value, but safety measures such as removing the bark, phloem, and cambium to reduce the risk of spreading the disease with shipment. Quarantines have been put in place in some states to reduce the potential movement of fungus or beetle from that region. On May 17th, 2010, the Director of the Michigan Department of Agriculture issued a quarantine from affected states to protect Michigan’s black walnut ecology and production. Contacting the appropriate entities about possible infections is important to stopping or slowing the spread of thousand cankers disease.
Control of the beetle vector is the most effective management technique for disease prevention. Conventional methods of tree thinning and the use of insecticides have been used to combat the western bark beetles, but are only effective before the beetles have colonized and before the fungus has invaded the tree. Other cultural techniques of sanitation and overall health of the oak trees by keeping up with watering, fertilizer or mulch needs, and pruning may help. It is very important to diagnose foamy bark canker disease correctly and promptly in order to manage the disease properly because if a tree is already infected, the removal of the tree is the most effective way to prevent the disease from spreading.
Management of Bleeding Canker of Chestnut is not definitive and treatments are currently being investigated. Because the pathogen can be spread by contaminated tools, cultural practices are important to management. Tools should be cleaned and used with caution after being used on infected trees. Recovery of trees is possible, so management strategies are focused on keeping trees healthy so they can recover. One recommendation is to add fertilizer that contains Potassium phosphate. Soil de-compaction, providing good drainage, and mulching to minimize fluctuation of soil temperature and moisture are all ways to improve or maintain tree health and to manage the pathogen.
Chemical methods can be used to help the tree maintain health and avoid progress of the disease. Management strategies are currently being developed. A study performed in 2015 examined the infection on trees and found that 41 F1 progeny parent tree source had the most promising lines of viability for resistance.
The best way to manage SDS is with a resistant variety. One issue is that most resistant varieties are only partially resistant so yield reductions may still occur. Another issue is that the plant needs resistance for SDS and SCN in order to gain true resistance because of their synergistic relationship and most varieties do not have resistance for both. Aside from resistance, the only other ways to control SDS are management practices.
These include:
- Avoid planting in cool, wet conditions
- Plant later when the soil has warmed up
- Try avoiding soil compaction as it creates wet spots in the soil that can increase plant stress and SDS infection rates
- Managing for SCN as this nematode often occurs alongside "F. virguliforme"
- Deep tillage to break up compaction and help the soil warm faster
One common management tactic used in other pathogen management plans is crop rotation. In some cases, disease severity can be reduced but most often it is not effective. This is because of chlamydospores and macroconidia as they can persist in soils for many years.
Fungicides are another common product used to control fungal pathogens. In-furrow applications and seed treatments with fungicides have some effect in decreasing disease instance but in most cases, the timing isn't right and the pathogen can still infect the plants. Foliar applications of fungicides have no effect on disease suppression for SDS because the fungi are found in the soil and mainly the roots of the plants. Most foliar fungicides do not move downward through plants, therefore having no effect on the pathogen.
There are many strategies to cultural management. Establishment of new trees that are disease free by trying to plant trees as soon as they are received from the nursery to reduce the amount of stress the tree undergoes to reduce the amount of dead tissue. Apply insecticides to prevent insects such as, peach tree borer to prevent disease causing conidia from entering wounded parts of the tree that the insects create. Prune trees appropriately and at the correct time when buds start to break to promote wide angled branching. Infection at pruning sites is less common when done during late spring because of the smaller amount of inoculum present at this time. Inspect trees occasionally and removed any dead branches to prevent infection at these sites. Training trees properly also helps foster decreased amount of disease. Training trees during the first season to have branches develop wide crotch angles to sustain long orchard life. Avoid excessive and late fertilization during cold season to avoid low temperature injury. Fertilize trees during the early spring to prevent cold-susceptible growth.
The genus Geosmithia (Ascomycota: Hypocreales) are generally saprophytic fungi affecting hardwoods. As of its identification in 2010, the species G. morbida is the first documented as a plant pathogen. The walnut twig beetle ("Pityophthorus juglandis") carries the mycelium and conidia of the fungus as it burrows into the tree. The beetle is currently only found in warmer climates, allowing for transmission of the fungus throughout the year. Generations of the beetle move to and from black walnut trees carrying the fungus as they create galleries, the adults typically moving horizontally, and the larvae moving vertically with the grain. As they move through the wood, the beetles deposit the fungus, which is then introduced into the phloem; cankers then develop around the galleries, quickly girdling the tree. The fungus has not been found to provide any value to the beetle. A study done by Montecchio and Faccoli in Italy in 2014 found that no fungal fruiting bodies were found around or on the cankers but in the galleries. Mycelium, and sometimes conidiophores and conidia were observed in the galleries as well. No sexual stage of the fungus has currently been found.
The foamy bark canker is a disease affecting oak trees in California caused by the fungus "Geosmithia pallida" and spread by the Western oak bark beetle ("Pseudopityopthorus pubipennis"). This disease is only seen through the symbiosis of the bark beetles and the fungal pathogen. The bark beetles target oak trees and bore holes through the peridermal tissues, making tunnels within the phloem. The fungal spores are brought into these tunnels by the beetles and begin to colonize the damaged cells inside the tunnels. Symptoms of the developing fungus include wet discoloration seeping from the beetle entry holes as the fungus begins to consume phloem and likely other tissues. If bark is removed, necrosis of the phloem can be observed surrounding the entry hole(s). As the disease progresses, a reddish sap and foamy liquid oozes from entry holes, thus giving the disease the name Foamy bark canker. Eventually after the disease has progressed, the tree dies. This disease is important because of its detrimental effects on oak trees and its ability to spread to several new Californian counties in just a couple years.
Sudden Death Syndrome (SDS) in Soybean plants quickly spread across the southern United States in the 1970s, eventually reaching most agricultural areas of the US. SDS is caused by a Fusarium fungi, more specifically the soil borne root pathogen "Fusarium virguliforme," formerly known as "Fusarium solani" f. sp. "glycines"."." Losses could exceed hundreds of millions of dollars in US soybean markets alone making it one of the most important diseases found in Soybeans across the US
Dead arm, sometimes grape canker, is a disease of grapes caused by a deep-seated wood rot of the arms or trunk of the grapevine. As the disease progresses over several years, one or more arms may die, hence the name "dead arm". Eventually the whole vine will die. In the 1970s, dead-arm was identified as really being two diseases, caused by two different fungi, "Eutypa lata" and "Phomopsis viticola" (syn. "Cryptosporella viticola").
Black pod disease is caused by many different "Phytophthora spp." pathogens all expressing the same symptoms in cocoa trees ("Theobroma cacao"). This pathogen if left untreated can destroy all yields; annually the pathogen can cause a yield loss of up to 1/3 and up to 10% of total trees can be lost completely. With the value of the cocoa industry throughout the world being so large there are much research and control efforts that go into these "Phytophthora spp." pathogens.
This pathogen can be located anywhere on the cocoa trees but is most noted for the black mummified look it will give to the fruit of the cocoa tree. Staying ahead of the pathogen is the best means of control, the pathogen can be greatly reduced if leaf litter is not allowed to stay on the ground and if the pathogen gets out of hand chemical control can be used. This pathogen is mostly found in tropical areas where the cocoa trees are located and need rainfall in order to spread its spores.
Bleeding canker of horse chestnut is a common canker of horse chestnut trees ("Aesculus hippocastanum", also known as conker trees) that is known to be caused by infection with several different pathogens.
Infections by the gram-negative fluorescent bacterium "Pseudomonas syringae" pathovar "aesculi" are a new phenomenon, and have caused most of the bleeding cankers on horse chestnut that are now frequently seen in Britain.
Dead arm is a disease that causes symptoms in the common grapevine species, "vitis vinifera", in many regions of the world. This disease is mainly caused by the fungal pathogen, "Phomopsis viticola", and is known to affect many cultivars of table grapes, such as Thompson Seedless, Red Globe, and Flame Seedless. Early in the growing season, the disease can delay the growth of the plant and cause leaves to turn yellow and curl. Small, brown spots on the shoots and leaf veins are very common first symptoms of this disease. Soil moisture and temperature can impact the severity of symptoms, leading to a systemic infection in warm, wet conditions. As the name of this disease suggests, it also causes one or more arms of the grapevine to die, often leading to death of the entire vine.
Canker and anthracnose generally refer to many different plant diseases of such broadly similar symptoms as the appearance of small areas of dead tissue, which grow slowly, often over years. Some are of only minor consequence, but others are ultimately lethal and therefore of major economic importance in agriculture and horticulture. Their causes include such a wide range of organisms as fungi, bacteria, mycoplasmas and viruses. The majority of canker-causing organisms are bound to a unique host species or genus, but a few will attack other plants. Weather and animals can spread canker, thereby endangering areas that have only slight amount of canker.
Although fungicides or bactericides can treat some cankers, often the only available treatment is to destroy the infected plant to contain the disease.
The application of copper fungicide has been shown to significantly reduce a great number of black pod incidences in Nigeria. Metalaxyl (Ridomil) and cuprous oxide (Perenox) were identified to be successful in increasing the number of harvested healthy pod compared to the application of fosetyl aluminium (Aliete) and control treatment. On top of that, the timing of fungicide application has some positive effect on the final pod yield where this plot produced greater yield than the unsprayed plot. The application was done before August, which is before the main disease epidemic that usually occurs in September and October.
The recommended standard for fungicide application to control black pod disease caused by "P. megakarya" for a season is 6 to 8 times of application in every 3–4 weeks. However, the adoption of recommended application was very low among farmers in Ghana. Therefore, an experiment with a reduced number of fungicide applications demonstrated that there was 25 to 45% reduction in disease incidence. In terms of disease control and yields, sanitation and three applications of Ridomil 72 plus (12% metalaxyl + 60% copper-1-oxide) fungicide showed a better control compared to sanitation alone and sanitation with one or two fungicide applications. However, reduced in fungicide application was shown to be significantly less effective than the recommended standard fungicide application.
It was suggested that the understanding regarding the source of inoculum, the amount of infective inoculum production and how the disease is disseminated is important in order to identify the appropriate and economical method in fungicide application as well as for an effective control of the disease. For example, the application of fungicide on the trunk will help farmers to control the spread of the disease up in the canopy, as it is difficult to reach the canopy during fungicide application. This will eventually save more time, labor and cost for disease management.
Grapevine trunk diseases (GTD) are the most destructive diseases of vineyards worldwide. Fungicides (such as sodium arsenite or 8-hydroxyquinoline, used to fight esca) with the potential to control GTD have been banned in Europe and there are no highly effective treatments available. Action to develop new strategies to fight these diseases are needed.
The following fungal species are responsible for grapevine trunk diseases:
- "Botryosphaeria dothidea" and other "Botryosphaeria" species, such as , "B. obtusa", "B. parva" and "B. australis",
- "Cylindrocarpon" spp., "Ilyonectria" spp., "Dactylonectria" spp. and "Campylocarpon" spp.(cause of black foot disease)
- "Diplodia seriata" (cause of bot canker)
- "Diplodia mutila" (cause of Botryosphaeria dieback)
- "Dothiorella iberica"
- "Dothiorella viticola"
- "Eutypa lata" (cause of Eutypa dieback)
- "Fomitiporia mediterranea" (cause of esca)
- "Lasiodiplodia theobromae" (cause of Botryosphaeria dieback)
- "Neofusicoccum australe"
- "Neofusicoccum luteum"
- "Neofusicoccom parvum"
- "Phaeoacremonium minimum" (cause of esca and Petri disease) and other "Phaeoacremonium" species
- "Phaeomoniella chlamydospora" (cause of esca and Petri disease)
The incubation period for foot-and-mouth disease virus has a range between one and 12 days. The disease is characterized by high fever that declines rapidly after two or three days, blisters inside the mouth that lead to excessive secretion of stringy or foamy saliva and to drooling, and blisters on the feet that may rupture and cause lameness. Adult animals may suffer weight loss from which they do not recover for several months, as well as swelling in the testicles of mature males, and in cows, milk production can decline significantly. Though most animals eventually recover from FMD, the disease can lead to myocarditis (inflammation of the heart muscle) and death, especially in newborn animals. Some infected ruminants remain asymptomatic carriers, but they nonetheless carry FMDV and may be able to transmit it to others. Pigs cannot serve as asymptomatic carriers.
Foot-and-mouth disease or hoof-and-mouth disease (Aphthae epizooticae) is an infectious and sometimes fatal viral disease that affects cloven-hoofed animals, including domestic and wild bovids. The virus causes a high fever for approximately two to six days, followed by blisters inside the mouth and on the feet that may rupture and cause lameness.
Foot-and-mouth disease (FMD) has very severe implications for animal farming, since it is highly infectious and can be spread by infected animals comparatively easily through contact with contaminated farming equipment, vehicles, clothing, feed and by domestic and wild predators. Its containment demands considerable efforts in vaccination, strict monitoring, trade restrictions, quarantines and occasionally the culling of animals.
Susceptible animals include cattle, water buffalo, sheep, goats, pigs, antelope, deer, and bison. It has also been known to infect hedgehogs and elephants; llamas and alpacas may develop mild symptoms, but are resistant to the disease and do not pass it on to others of the same species. In laboratory experiments, mice, rats, and chickens have been successfully infected by artificial means, but they are not believed to contract the disease under natural conditions. Humans are very rarely infected.
The virus responsible for the disease is a picornavirus, the prototypic member of the genus "Aphthovirus". Infection occurs when the virus particle is taken into a cell of the host. The cell is then forced to manufacture thousands of copies of the virus, and eventually bursts, releasing the new particles in the blood. The virus is genetically highly variable, which limits the effectiveness of vaccination.
Diagnosis is mostly based on the clinical appearance and the medical history. The most important diagnostic feature is a history of recurrent, self healing ulcers at fairly regular intervals. Although there are many causes of oral ulceration, "recurrent" oral ulceration has relatively few causes, most commonly aphthous stomatitis, but rarely Behçet's disease, erythema multiforme, ulceration associated with gastrointestinal disease, and recurrent intra-oral herpes simplex infection. A systemic cause is more likely in adults who suddenly develop recurrent oral ulceration with no prior history.
Special investigations may be indicated to rule out other causes of oral ulceration. These include blood tests to exclude anemia, deficiencies of iron, folate or vitamin B12 or celiac disease. However, the nutritional deficiencies may be latent and the peripheral blood picture may appear relatively normal. Some suggest that screening for celiac disease should form part of the routine work up for individuals complaining of recurrent oral ulceration. Many of the systemic diseases cause other symptoms apart from oral ulceration, which is in contrast to aphthous stomatitis where there is isolated oral ulceration. Patch testing may be indicated if allergies are suspected (e.g. a strong relationship between certain foods and episodes of ulceration). Several drugs can cause oral ulceration (e.g. nicorandil), and a trial substitution to an alternative drug may highlight a causal relationship.
Tissue biopsy is not usually required, unless to rule out other suspected conditions such as oral squamous cell carcinoma. The histopathologic appearance is not pathognomonic (the microscopic appearance is not specific to the condition). Early lesions have a central zone of ulceration covered by a fibrinous membrane. In the connective tissue deep to the ulcer there is increased vascularity and a mixed inflammatory infiltrate composed of lymphocytes, histiocytes and polymorphonuclear leukocytes. The epithelium on the margins of the ulcer shows spongiosis and there are many mononuclear cells in the basal third. There are also lymphocytes and histiocytes in the connective tissue surrounding deeper blood vessels near to the ulcer, described histologically as "perivascular cuffing".
By definition, there is no serious underlying medical condition, and most importantly, the ulcers do not represent oral cancer nor are they infectious. However, aphthae are capable of causing significant discomfort. There is a spectrum of severity, with symptoms ranging from a minor nuisance to disabling. Due to pain during eating, weight loss may develop as a result of not eating in severe cases of aphthous stomatitis. Usually, the condition lasts for several years before spontaneously disappearing in later life.
Diagnosis of mouth ulcers usually consists of a medical history followed by an oral examination as well as examination of any other involved area. The following details may be pertinent: The duration that the lesion has been present, the location, the number of ulcers, the size, the color and whether it is hard to touch, bleeds or has a rolled edge. As a general rule, a mouth ulcer that does not heal within 2 or 3 weeks should be examined by a health care professional who is able to rule out oral cancer (e.g. a dentist, oral physician, oral surgeon, or maxillofacial surgeon). If there have been previous ulcers which have healed, then this again makes cancer unlikely.
An ulcer that keeps forming on the same site and then healing may be caused by a nearby sharp surface, and ulcers that heal and then recur at different sites are likely to be RAS. Malignant ulcers are likely to be single in number, and conversely, multiple ulcers are very unlikely to be oral cancer. The size of the ulcers may be helpful in distinguishing the types of RAS, as can the location (minor RAS mainly occurs on non-keratinizing mucosa, major RAS occurs anywhere in the mouth or oropharynx). Induration, contact bleeding and rolled margins are features of a malignant ulcer. There may be nearby causative factor, e.g. a broken tooth with a sharp edge that is traumatizing the tissues. Otherwise, the person may be asked about problems elsewhere, e.g. ulceration of the genital mucous membranes, eye lesions or digestive problems, swollen glands in neck (lymphadenopathy) or a general unwell feeling.
The diagnosis comes mostly from the history and examination, but the following special investigations may be involved: blood tests (vitamin deficiency, anemia, leukemia, Epstein-Barr virus, HIV infection, diabetes) microbiological swabs (infection), or urinalysis (diabetes). A biopsy (minor procedure to cut out a small sample of the ulcer to look at under a microscope) with or without immunofluorescence may be required, to rule out cancer, but also if a systemic disease is suspected. Ulcers caused by local trauma are painful to touch and sore. They usually have an irregular border with erythematous margins and the base is yellow. As healing progresses, a keratotic (thickened, white mucosa) halo may occur.
Many conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square meters, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin. Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands form from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues.
The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Nourishment is provided to these layers by diffusion from the dermis, since the epidermis is without direct blood supply. The epidermis contains four cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. Of these, keratinocytes are the major component, constituting roughly 95 percent of the epidermis. This stratified squamous epithelium is maintained by cell division within the stratum basale, in which differentiating cells slowly displace outwards through the stratum spinosum to the stratum corneum, where cells are continually shed from the surface. In normal skin, the rate of production equals the rate of loss; about two weeks are needed for a cell to migrate from the basal cell layer to the top of the granular cell layer, and an additional two weeks to cross the stratum corneum.
The dermis is the layer of skin between the epidermis and subcutaneous tissue, and comprises two sections, the papillary dermis and the reticular dermis. The superficial papillary dermis with the overlying rete ridges of the epidermis, between which the two layers interact through the basement membrane zone. Structural components of the dermis are collagen, elastic fibers, and ground substance. Within these components are the pilosebaceous units, arrector pili muscles, and the eccrine and apocrine glands. The dermis contains two vascular networks that run parallel to the skin surface—one superficial and one deep plexus—which are connected by vertical communicating vessels. The function of blood vessels within the dermis is fourfold: to supply nutrition, to regulate temperature, to modulate inflammation, and to participate in wound healing.
The subcutaneous tissue is a layer of fat between the dermis and underlying fascia. This tissue may be further divided into two components, the actual fatty layer, or panniculus adiposus, and a deeper vestigial layer of muscle, the panniculus carnosus. The main cellular component of this tissue is the adipocyte, or fat cell. The structure of this tissue is composed of septal (i.e. linear strands) and lobular compartments, which differ in microscopic appearance. Functionally, the subcutaneous fat insulates the body, absorbs trauma, and serves as a reserve energy source.
Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses, as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails). While only a small number of skin diseases account for most visits to the physician, thousands of skin conditions have been described. Classification of these conditions often presents many nosological challenges, since underlying etiologies and pathogenetics are often not known. Therefore, most current textbooks present a classification based on location (for example, conditions of the mucous membrane), morphology (chronic blistering conditions), etiology (skin conditions resulting from physical factors), and so on. Clinically, the diagnosis of any particular skin condition is made by gathering pertinent information regarding the presenting skin lesion(s), including the location (such as arms, head, legs), symptoms (pruritus, pain), duration (acute or chronic), arrangement (solitary, generalized, annular, linear), morphology (macules, papules, vesicles), and color (red, blue, brown, black, white, yellow). Diagnosis of many conditions often also requires a skin biopsy which yields histologic information that can be correlated with the clinical presentation and any laboratory data.
MRI is the most sensitive imaging technique that can be used for diagnosing NBD. As for the parenchymal NBD, medical doctors mainly monitor the upper brainstem lesion. In fact, it is possible that lesions extends to thalamus and basal ganglia. Another advantage of using MRI is the ability to perform Diffusion-weighted imaging, or diffusion MRI. This technique is the most sensitive tool to image an acute infarct. In the case of NBD, Diffusion MRI can determine whether the lesion were due to cerebral infarction. In other words, it can distinguish NBD from non-NBD neural disease. When only spinal cord is affected by NBD, brain looks perfectly normal when scanned by MRI. Therefore, it is necessary to scan the spinal cord as well when diagnosing possible NBD involvement. As for the non-parenchymal NBD, venous sinus thrombosis can be detected.
Treatment is cause-related, but also symptomatic if the underlying cause is unknown or not correctable. It is also important to note that most ulcers will heal completely without any intervention. Treatment can range from simply smoothing or removing a local cause of trauma, to addressing underlying factors such as dry mouth or substituting a problem medication. Maintaining good oral hygiene and use of an antiseptic mouthwash or spray (e.g. chlorhexidine) can prevent secondary infection and therefore hasten healing. A topical analgesic (e.g. benzydamine mouthwash) may reduce pain. Topical (gels, creams or inhalers) or systemic steroids may be used to reduce inflammation. An antifungal drug may be used to prevent oral candidiasis developing in those who use prolonged steroids. People with mouth ulcers may prefer to avoid hot or spicy foods, which can increase the pain. Self-inflicted ulceration can be difficult to manage, and psychiatric input may be required in some people.
Chronic ulcerative stomatitis is a recently discovered condition with specific immunopathologic features. It is characterized by erosions and ulcerations which relapse and remit. Lesions are located on the buccal mucosa (inside of the cheeks) or on the gingiva (gums). The condition resembles Oral lichen planus when biopsied.
The diagnosis is made with Immunofluorescence techniques, which shows circulating and tissue-bound autoantibodies (particulate stratified squamous-epithelium-specific antinuclear antibody) to DeltaNp63alpha protein, a normal component of the epithelium. Treatment is with hydroxychloroquine.