Thermoacoustic tomography with variable sound speed

We study the mathematical model of thermoacoustic tomography in media with a variable speed for a fixed time interval, greater than the diameter of the domain. In case of measurements on the whole boundary, we give an explicit solution in terms of a Neumann series expansion. We give necessary and sufficient conditions for uniqueness and stability when the measurements are taken on a part of the boundary

Transplantation of ex vivo expanded limbal stem cells in neurotrophic keratopathy - a case report

Представяме клиничен случай на невротрофична кератопатия, асоциирана с унилатерална лимбална стволовоклетъчна инсуфициенция. Извършена бе трансплантация на автоложни ех vivo размножени лимбални стволови клетки. Използваните диагностични методи включват биомикроскопия, микробиологично изследване на секрет от конюнктива и роговична лезия, полимеразно верижна реакция на преднокамерна течност за херпес вирусна ДНК, оптична кохерентна томография на преден очен сегмент. Поради липсата на подобрение след консервативно лечение се проведе минимално инвазивиа лимбална биопсия и трансплантация на амниотична мембрана. Получените автоложни стволови клетки бяха размножени ех vivo по иновативен протокол без ксенобиотични продукти с преносител нативна амниотична мембрана. След получаване на достатъчно епителни слоеве ех vivo, се направи биологично покритие с готовия трансплантат. Постоперативно роговичната повърхност бе напълно епителизирана и зрителната острота се подобри значително. Наблюдава се регрес на неоваскуларните съдове и всички симптоми на хронично възпаление се облекчиха. Трансплантацията на автоложни ех vivo размножени лимбални стволови клетки с преностител амниотична мембрана може да бъде ефективен метод за лечение на невротрофична кератопатия, асоциирана с лимбална стволовоклетъчна инсуфициенция.We present a case of neurotrophic keratopathy associated with limbal stem cell deficiency, treated by transplantation of autologous ex vivo expanded limbal stem cells. The applied diagnostic methods include slit-lamp examination, microbiological samples from conjunctiva and corneal lesion, polymerase chain reaction of aqueous humor for herpes virus DNA, anterior segment optical coherence tomography. Since no improvement was observed with conservative treatment, a minimally invasive limbal biopsy and transplantation of amniotic membrane were performed. The collected autologous limbal stem cells were expanded ex vivo using an innovative protocol without xenobiotic products on intact amniotic membrane. After sufficient epithelial layers were obtained ex vivo the graft was transplanted on the ocular surface of the patient. Postoperatively the corneal surface was completely covered by epithelium, visual acuity improved significantly. Regression of neovascular vessels was observed and all symptoms of chronic inflammation were alleviated. Transplantation of ex vivo expanded limbal stem cells on amniotic membrane can be an effective treatment method for neurotrophic keratopathy, associated with limbal stem cell deficiency

Limbal stem cell deficiency - concept and treatment

Лимбалната стволовоклетъчна инсуфициенция стои в основата на множество заболявания и може да бъде причина за неуспех от различни оперативни интервенции на очната повърхност, включително пенетрираща кератопластика. Класическата клинична картина включва триадата конюнктивализация, неоваскуларизация и хронично възпаление, които се доказват клинично и инструментално чрез импресиоина цитология, конфокална микроскопия и други образни методи. Лечението на лимбалната стволовоклетъчна инсуфициенция изисква комплексен подход и създаване на оптимална среда за преживяване на лимбалните епителни клетки чрез коригиране на всички придружаващи патофизиологични отклонения. Нова насока в оперативното лечение е ех vivo размножаването на автоложни лимбални стволови клетки, получени от минимално инвазивиа лимбална биопсия. С нарастващото значение на заболяването в практиката постоянно навлизат иновативни методи за възстановяване на нормална очна повърхност и осигуряване на висока зрителна острота.Limbal stem cell deficiency is implicated in many diseases and can be a reason for failure of different ocular surface reconstruction interventions, including penetrating keratoplasty. Classic clinical presentation includes the triad conjunctivalization, neovascularization, and chronic inflammation demonstrated by clinical and instrumental methods like impression cytology, confocal microscopy, and other imaging techniques. Management of limbal epithelial stem cell deficiency requires a complex approach and providing optimal conditions for limbal stem cell survival by correcting all coexistent pathophysiologic aberrations. A new direction in operative treatment is ex vivo expansion of autologous limbal epithelial stem cells obtained by minimally invasive limbal biopsy. With growing practical significance of the disease new innovative methods for ocular surface reconstruction continue to arise, aiming at the best visual outcome

Endogenous transforming growth factor β1 suppresses inflammation and promotes survival in adult CNS

Transforming growth factor β1 (TGFβ1) is a pleiotropic cytokine with potent neurotrophic and immunosuppressive properties that is upregulated after injury, but also expressed in the normal nervous system. In the current study, we examined the regulation of TGFβ1 and the effects of TGFβ1 deletion on cellular response in the uninjured adult brain and in the injured and regenerating facial motor nucleus. To avoid lethal autoimmune inflammation within 3 weeks after birth in TGFβ1-deficient mice, this study was performed on a T- and B-cell-deficient RAG2-/- background. Compared with wild-type siblings, homozygous deletion of TGFβ1 resulted in an extensive inflammatory response in otherwise uninjured brain parenchyma. Astrocytes increased in GFAP and CD44 immunoreactivity; microglia showed proliferative activity, expression of phagocytosis-associated markers [αXβ2, B7.2, and MHC1 (major histocompatibility complex type 1)], and reduced branching. Ultrastructural analysis revealed focal blockade of axonal transport, perinodal damming of axonal organelles, focal demyelination, and myelin debris in granule-rich, phagocytic microglia. After facial axotomy, absence of TGFβ1 led to a fourfold increase in neuronal cell death (52 vs 13%), decreased central axonal sprouting, and significant delay in functional recovery. It also interfered with the microglial response, resulting in a diminished expression of early activation markers [ICAM1 (intercellular adhesion molecule 1), α6β1, and αMβ2] and reduced proliferation. In line with axonal and glial findings in the otherwise uninjured CNS, absence of endogenous TGFβ1 also caused an ∼10% reduction in the number of normal motoneurons, pointing to an ongoing and potent trophic role of this anti-inflammatory cytokine in the normal as well as in the injured brain. Copyright © 2007 Society for Neuroscience

Cocompact lattices in locally pro-p-complete rank-2 Kac-Moody groups

We initiate an investigation of lattices in a new class of locally compact groups: so-called locally pro-p-complete Kac-Moody groups. We discover that in rank 2 their cocompact lattices are particularly well- behaved: under mild assumptions, a cocompact lattice in this completion contains no elements of order p. This statement is still an open question for the Caprace-Rémy-Ronan completion. Using this, modulo results of Capdeboscq and Thomas, we classify edge-transitive cocompact lattices and describe a cocompact lattice of minimal covolume. Bibliography: 22 titles

Annual streamflow of Bulgaria in the beginning of XXI century

Estimating the annual streamflow under the climate change is a challenge for hydrology science and an important task for geography as well. There is no analysis about the basic statistical parameters of the annual runoff time-series after 2000 in scientific investigations in the country. This paper describes Bulgaria’s annual streamflow during 2000 – 2016 for the main catchment areas in the country (Danube watershed, Black Sea catchment area and the Aegean Sea watershed). The work is based on publicly available data of annual streamflow. The screening of the hydrological data for homogeneity, randomness, probability distribution and the trend is based on statistical methods. The obtained results show regional differences in scale of fluctuation of hydrological variables around the norm for the referent periods, in the years with maximum and with the minimum volume of the water resources, in the probability distribution of empirical data. All timeseries are homogeneous, randomly and with the absence of the trend. The work draws a conclusion that annual streamflow of main catchment areas of Bulgaria in the beginning of XXI century is in the normal frame and with larger fluctuation than the referent periods and that the time-series statistical models need confirmation using the larger base of hydrological data. This work is the first estimation of the annual streamflow during XXI century in Bulgaria by major watersheds and it gives a new information about hydrological processes in the country

Thermoacoustic tomography arising in brain imaging

We study the mathematical model of thermoacoustic and photoacoustic tomography when the sound speed has a jump across a smooth surface. This models the change of the sound speed in the skull when trying to image the human brain. We derive an explicit inversion formula in the form of a convergent Neumann series under the assumptions that all singularities from the support of the source reach the boundary

Parallelizing multiple precision Taylor series method for integrating the Lorenz system

A hybrid MPI+OpenMP strategy for parallelizing multiple precision Taylor series method is proposed, realized and tested. To parallelize the algorithm we combine MPI and OpenMP parallel technologies together with GMP library (GNU miltiple precision libary) and the tiny MPIGMP library. The details of the parallelization are explained on the paradigmatic model of the Lorenz system. We succeed to obtain a correct reference solution in the rather long time interval - [0,7000]. The solution is verified by comparing the results for 2700-th order Taylor series method and precision of ~ 3374 decimal digits, and those with 2800-th order and precision of ~ 3510 decimal digits. With 192 CPU cores in Nestum cluster, Sofia, Bulgaria, the 2800-th order computation was ~ 145 hours with speedup ~ 105.Comment: arXiv admin note: text overlap with arXiv:1908.0930

Transplantation of ex vivo expanded limbal stem cells

Цел : Цел на настоящото проучване е да се изследват възможностите на трансплантацията на ех vivo размножени автоложни лимбални епителни стволови клетки като метод за лечение на повърхностни очни заболявания. Материали и методи: Трансплантации на автоложни ех vivo размножени стволови клетки бяха извършени на четирима пациенти на средна възраст 56.5 години преминали през Клиника по Очни болести към УМБАЛ "Александровска". Всички те демонстрираха клинични белези на унилатерална лимбална стволовоклетъчна инсуфициенция, асоциирана с трофични заболявания на очната повърхност, която бе демонстрирана чрез импресионна цитология. След получаване на информирано съгласие бе проведена минимално инвазивиа лимбална биопсия. Получените материали бяха обработени по иновапiВен протокол за клетъчни култури без употреба на ксенобиотични продукти. Четиринадесет дни по-късно бе направено биологично покритие с готовия трансплантат. Проследяване на състоянието се извърши чрез оптична кохерентна томография на преден очен сегмент преди и след трансплантацията. Критериите з a успех от трансплантацията на ех vivo размножени стволови клетки включват: 1. пълна епителизация на роговичната повърхност; 2. редукция на неоваскуларизацията или пълното ѝ изчезване; 3. възстановяване на нормални прозрачност, дебелина и рефлекс на роговицата; 4. подобрение на зрителната острота. Резултати : При всички пациенти се наблюдава подобрение на клиничната картина и субективните оплаквания. При трИ!Vш от изследваните бяха изпълнени четирите критерия за успешна трансплантация. При един от случаите не бе отчетено подобрение в зрителната острота, поради засягане на зрителния нерв от туморен процес. Не се наблюдаваха реакции на отхвърляне на трансплантата. Лимбалната биопсия не индуцира инсуфициенция на донорното око. Изводи : Трансплантацията на ех vivo размножени автоложни лимбални стволови клетки е ефективен и безопасен метод за възстановяване на очната повърхност, който може да бъде приложен при различни заболявания, асоциирани с лимбална стволовоклетъчна инсуфициенция.Purpose: To investigate the application of autologous ex vivo expanded limbal stem cell transplantation in the management of ocular surface disease. Materials and methods: Autologous ex vivo expanded stem cells were transplanted to four patients with mean age 56.5 years from the Depmtment of Ophthalmology, University Hospital Alexandrovska. All patients presented signs of unilateral limbal stem cell deficiency, associated with trophic disease of the ocular surface, which was demonstrated on impression cytology. After informed consent was obtained a minimally invasive limbal biopsy was performed. The limbal materials were cultured using a novel protocol without additional xenobiotic products. The grafts were transplanted after fourteen days. Anterior segment optical coherence tomography before and after the intervention was used for assessment of the condition. Success of the procedure was defined as 1. Complete epithelialization of the corneal surface, 2. partial or complete reduction of neovascularization, 3. achieving normal corneal transparency, thickness and reflex, 4. visual acuity improvement. Results: Clinical recovery was observed in all patients, as well as improvement of subjective ocular comfort. In three of the cases all four success criteria were met. Visual acuity of one patient did not change, due to neoplastic process, pervading the optic nerve. No graft rejection reactions were observed. Limbal biopsy did not induce limbal stem cell deficiency in the donor eye. Conclusion: Transplantation of autologous ex vivo expanded limbal stem cells is an effective and safe method for ocular surface reconstruction, which can be applied in different conditions, associated with limbal stem cell deficiency

NGF-ome: its metabotrophic expression. Homage to Rita Levi-Montalcini

Nowadays, in the postgenome time, many "-ome" studies have emerged including proteome, transcriptome, interactome, metabolome, adipokinome, connectome. In this vein, the catchall term NGF-ome embodies all the actions of NGF in health and disease. Accordingly, the present Festschrift, also tabula gratulatoria, is to honor and acknowledge the contributions of the distinguished neuroscientist and magistra Rita Levi-Montalcini, the Nobel Prize winner-1986 for the discoverer of NGF. Today, NGF and another neurotrophin, brain-derived neuroptrophic factor (BDNF), are well recognized to mediate multiple biological phenomena, ranging from the neurotrophic through immunotrophic and epitheliotrophic to metabotrophic effects. These latter effects are involved in the maintenance of cardiometabolic homeostasis (glucose and lipid metabolism as well as energy balance, and cardioprotection). Circulating and/or tissue levels of NGF and BDNF are altered in cardiometabolic diseases (atherosclerosis, obesity, type 2 diabetes, metabolic syndrome, and type 3 diabetes/Alzheimer's disease). A hypothesis thus emerged that a metabotrophic deficit due to the reduction of NGF/BDNF availability and/or utilization may be implicated in the pathogenesis of cariometabolic and neurodegenerative diseases. The present challenge is therefore to cultivate a metabotrophic thinking about how we can modulate NGF/BDNF secretion and signaling for the benefit of human cardiometabolic and mood health.Biomedical Reviews 2010; 21: 25-29