2,585 research outputs found
ON THE PROBLEM OF MEAN PERIODIC EXTENSION
This paper is devoted to a study of the following version
of the mean periodic extension problem:
(i) Suppose that ∈ ℰ′ (R^), ≥ 2, and is a non-empty
subset of R^. Let ∈ (). What conditions guarantee that there is an ∈ (R^) coinciding with on , such that * = 0 in R^ ? (ii) If such an extension exists, then estimate the growth of at infinity.
In this paper, we present a solution of this problem for a broad class of distributions in the case when is a segment in R^n
Morphological and ophthalmoscopic features of epiretinal membranes after intravitreal injection of various doses of aflibercept in patients with proliferative diabetic retinopathy
Background: Although methods are available to treat proliferative diabetic retinopathy (PDR), 30% of cases progress, which is an indication for vitrectomy.
Purpose: To investigate the ophthalmoscopic and morphological features of epiretinal membranes (ERMs) in patients with PDR depending on the dose of preoperative intravitreal aflibercept (PIA).
Material and Methods: Seventy-five patients (75 eyes) with PDR and the presence of fibrovascular ERM with a marked proliferative component were involved in the study. Patients were divided into three groups: eyes of group 1 or control group (31 eyes) received vitrectomy without PIA; group 2 (17 eyes), PIA 1.0 mg; and group 3 (27 eyes), PIA 2.0 mg. We performed a histological study on specimens of fibrovascular ERMs surgically obtained from patients to determine the microscopic features of these membranes.
Results: There was ophthalmoscopic and microscopic evidence that aflibercept pretreatment in vitrectomy for PDR resulted in fibrosis of the ERM. The extent of fibrosis of the ERM and obliteration of newly formed blood vessels in the ERM depended on the dose of PIA. Complete obliteration of newly formed blood vessels in the ERM was observed as early as day 3 after 2.0-mg intravitreal aflibercept injection compared to day 5 after 1.0-mg intravitreal aflibercept injection. Pretreatment with 1.0-mg intravitreal aflibercept in vitrectomy for PDR reduced the probability of complications associated with ERM contraction, worsening of the tractional component and the development of a retinal break
Влияние химических средств защиты растений на засоренность посадок и продуктивность картофеля в степной зоне Хакасии
In the Russian Federation, large areas in farms of various forms of ownership are devoted to the potato. The wide range of uses for this crop is particularly relevant to the industry. Cultivation technology in general, particularly some elements of agronomic techniques, may have specific differences depending on the region and the soil and climate zone. An invariable negative biotic factor for any area remains weeds, which account for the agro-technological costs. The biological group and species composition of weeds significantly influence potato yields. Chemical crop protection products (herbicides) have a significant effect in reducing the negative impact of the factor. Therefore, the aim of the study is the effect of different herbicide preparations on weed infestation and potato productivity in the conditions of the steppe zone of the Republic of Khakassia. Experiments were laid from 2018 to 2020 on dark chestnut soil in the steppe zone of the Republic of Khakassia. The authors chose a medium-early potato variety of Siberian selection Tuleevsky as an object of research. The recommended potato cultivation technology for this zone was used in the study. Herbicides were selected for preemergence application (Gezagard, Lazurit, Sukhovey, Tornado), applied 20-25 days after planting, before the mass sprouting of plants. The hydrothermal coefficient changed from 1.68 to 1.85 in the years of research. Using herbicides reduced the number of monocotyledonous weeds by 18,9 - 26,7% and dicotyledonous weeds by 38,5 - 46,1% by the harvest period. Reduction of competition with weeds for life factors allowed increased biometric indicators of potatoes (height of a plant, number of leaves, weight of haulm). The increase of biometric parameters of potatoes has essentially affected the growth of economic productivity of leaves from 9,3 to 13,2 %. The yield of potatoes has increased on 3,6-6,5 t/hectare (at the maximum value at a background of Lazurite preparation) due to the increase of efficiency of work of assimilating apparatus. The use of herbicides on potatoes allows increasing the level of profitability of production by 22,3-56,4%.Картофелем в Российской Федерации заняты большие площади в хозяйствах различных форм собственности, так как широкий спектр использования культуры определяет особую актуальность её для отрасли. В зависимости от региона и почвенно-климатической зоны технология возделывания в целом и в частности некоторые элементы агротехники могут иметь определенные различия. Неизменным отрицательным биотическим фактором для любой местности, обусловливающим большую долю агротехнологических затрат, остаются сорные растения. Биологическая группа и видовой состав сорняков оказывают существенное влияние на урожайность картофеля. Значительным эффектом, позволяющим снизить отрицательное воздействие фактора, обладают химические средства защиты растений (гербициды). Поэтому целью нашего исследования было изучение влияния различных гербицидных препаратов на засоренность посадок и продуктивность картофеля в условиях степной зоны Хакасии. Опыты закладывали в 2018–2020 гг. на темно-каштановой почве в степной зоне Хакасии. В качестве объекта исследований был выбран среднеранний сорт картофеля сибирской селекции Тулеевский. В исследованиях использовали рекомендованную технологию возделывания картофеля для данной зоны. Гербицидные препараты подбирали для довсходового внесения (Гезагард, Лазурит, Суховей, Торнадо), которые применяли через 20–25 дней после посадки, до массовых всходов растений. В годы исследований гидротермический коэффициент изменялся от 1,68 до 1,85. Использование гербицидов позволило снизить количество однодольных сорняков на 18,9–26,7% и на 38,5–46,1% – двудольных к периоду уборки культуры. Снижение конкуренции с сорными растениями за факторы жизни позволило повысить биометрические показатели картофеля (высоту растения, количество листьев, массу ботвы). Это существенным образом сказалось на повышении хозяйственной продуктивности листьев – от 9,3 до 13,2%. Как следствие повышения эффективности работы ассимиляционного аппарата урожайность возросла на 3,6–6,5 т/га (в максимальном значении на фоне препарата Лазурит). Использование гербицидов на картофеле позволяет повысить уровень рентабельности производства на 22,3–56,4%
Effect of experimental type 2 diabetes complicated by pyelonephritis on ultrastructural changes in the choroid, retina and nephrons
The clinical and morphological picture of diabetic microangiopathy
is rather specific. Diabetic retinal ischemia can lead to irreversible damage to
retinal neural elements and choroidal capillaries. Diabetic nephropathy can lead
to progressive renal dysfunction and chronic renal failure. Choroidal and retinal
capillaries are structurally and functionally similar to those of the intestinal
mucosa and renal tissue.
Purpose: To assess vascular ultrastructural changes in the choroid, retina, and
renal glomerular and tubular system in a rat model of pyelonephritis in the
presence of type 2 diabetes.
Material and Methods: Samples were obtained from 95 Wistar rats divided into
three groups: group 1 (or control group) of 30 intact animals; group 2 of 15
animals with type 2 diabetes induced by intraperitoneal streptozotocin 15.0 mg/
kg for 5 consecutive days; and group 3 of 50 animals with acute pyelonephritis
in the presence of type 2 diabetes (streptozotocin 35.0 mg/kg on 2 days spaced
by a week). Acute pyelonephritis was induced by Escherichia coli administration
(107 CFU/kg) rectally. The ultrastructure of rat choroidal, retinal and renal
glomerular-and-tubular vessels was examined with electron microscopy (PEM-
100-01 electron microscope).
Results: In rats with induced type 2 diabetes, the most significant ocular vascular
changes and renal vascular changes were found in endothelial cells. These
changes included findings of vacuolar degeneration in some epithelial cells, basal
membrane thickening and focal necrosis of individual epithelial cells. Vessel
lumens appeared focally narrowed or expanded, with red blood cells forming
clumps or sludge in lumens. Some capillaries were obliterated. These changes
obviously caused secondary changes in the surrounding structures. Common
ocular changes included focal destruction in retinal pigment epithelium cells,
destruction of retinal photoreceptor inner segments and choroidal stromal edema.
Common renal changes included destruction of the podocytes of the glomerular
capillary network and homogenization of the basal membrane. Vascular
ultrastructural changes in the renal glomerular system were more marked in rats
with experimental type 2 diabetes and pyelonephritis than in those with type 2
diabetes only.
Conclusion: Electron microscopy micrographs demonstrated the ultrastructural
changes in the retinal and uveal vascular systems which were of a similar type
to those in the renal glomerular-and-tubular system in rats with experimental
pyelonephritis in the presence of type 2 diabetes
Effect of experimental type 2 diabetes complicated by pyelonephritis on ltrastructural changes in the choroid, retina and nephrons
Background: The clinical and morphological picture of diabetic microangiopathy is rather specific. Diabetic retinal ischemia can lead to irreversible damage to retinal neural elements and choroidal capillaries. Diabetic nephropathy can lead to progressive renal dysfunction and chronic renal failure. Choroidal and retinal capillaries are structurally and functionally similar to those of the intestinal mucosa and renal tissue.
Purpose: To assess vascular ultrastructural changes in the choroid, retina, and renal glomerular and tubular system in a rat model of pyelonephritis in the presence of type 2 diabetes.
Material and Methods: Samples were obtained from 95 Wistar rats divided into three groups: group 1 (or control group) of 30 intact animals; group 2 of 15 animals with type 2 diabetes induced by intraperitoneal streptozotocin 15.0 mg/kg for 5 consecutive days; and group 3 of 50 animals with acute pyelonephritis in the presence of type 2 diabetes (streptozotocin 35.0 mg/kg on 2 days spaced by a week). Acute pyelonephritis was induced by Escherichia coli administration (107 CFU/kg) rectally. The ultrastructure of rat choroidal, retinal and renal glomerular-and-tubular vessels was examined with electron microscopy (PEM-100-01 electron microscope).
Results: In rats with induced type 2 diabetes, the most significant ocular vascular changes and renal vascular changes were found in endothelial cells. These changes included findings of vacuolar degeneration in some epithelial cells, basal membrane thickening and focal necrosis of individual epithelial cells. Vessel lumens appeared focally narrowed or expanded, with red blood cells forming clumps or sludge in lumens. Some capillaries were obliterated. These changes obviously caused secondary changes in the surrounding structures. Common ocular changes included focal destruction in retinal pigment epithelium cells, destruction of retinal photoreceptor inner segments and choroidal stromal edema. Common renal changes included destruction of the podocytes of the glomerular capillary network and homogenization of the basal membrane. Vascular ultrastructural changes in the renal glomerular system were more marked in rats with experimental type 2 diabetes and pyelonephritis than in those with type 2 diabetes only.
Conclusion: Electron microscopy micrographs demonstrated the ultrastructural changes in the retinal and uveal vascular systems which were of a similar type to those in the renal glomerular-and-tubular system in rats with experimental pyelonephritis in the presence of type 2 diabetes
SF3B1-mutated chronic lymphocytic leukemia shows evidence of NOTCH1 pathway activation including CD20 downregulation
Chronic lymphocytic leukemia (CLL) is characterized by a low CD20 expression, in part explained by an epigenetic-driven downregulation triggered by mutations of the NOTCH1 gene. In the present study, by taking advantage of a wide and well-characterized CLL cohort (n=537), we demonstrate that CD20 expression is downregulated in SF3B1-mutated CLL in an extent similar to NOTCH1-mutated CLL. In fact, SF3B1-mutated CLL cells show common features with NOTCH1-mutated CLL cells, including a gene expression profile enriched of NOTCH1-related gene sets and elevated expression of the active intracytoplasmic NOTCH1. Activation of the NOTCH1 signaling and down-regulation of surface CD20 in SF3B1-mutated CLL cells correlate with over-expression of an alternatively spliced form of DVL2, a component of the Wnt pathway and negative regulator of the NOTCH1 pathway. These findings are confirmed by separately analyzing the CD20-dim and CD20-bright cell fractions from SF3B1-mutated cases as well as by DVL2 knock-out experiments in CLL-like cell models. Altogether, the clinical and biological features that characterize NOTCH1-mutated CLL may also be recapitulated in SF3B1-mutated CLL, contributing to explain the poor prognosis of this CLL subset and providing the rationale for expanding novel agents-based therapies to SF3B1-mutated CLL
Effect of recombinant erythropoietin on structural changes of the retina, hemoglobin concentration and erythrocytes quantity in peripheral blood in streptozotocin-induced diabetic rats
Introduction. Recently the role of erythropoietin (Epo) in the development of diabetic
retinopathy has been studied.
Purpose. To determine the effect of recombinant erythropoietin (rEpo) on structural
peculiarities of the retina, hemoglobin concentration and erythrocyte quantity
in peripheral blood in streptozotocin-induced diabetes animals.
Methods. 30 Vistar rats were included in the experiment. Diabetes was simulated
using a single intraperitoneal injection of streptozotocin in a dose of 65 mg per 1
kg body weight. All rats were divided into three groups, each of 10 rats (20 eyes).
Group 1 consisted of intact rats; group 2 — of streptozotocin-induced diabetes rats
not receiving rEpo; group 3 — of streptozotocin-induced diabetes rats receiving
rEpo. REpo administration started on the 10th day in a dose of 60 units per 1 kg of
body weight three times a week during two weeks. Results. Epo was detected in peripheral blood and vitreous of intact rats. Erythrocyte
quantity and hemoglobin concentration in blood didn’t change in rats of
Group 2. REpo administration in Group 3 led to significant increase of Epo concentration
in peripheral blood and vitreous, increase of erythrocyte quantity and
hemoglobin concentration. Development of retinal edema, vacuolar degeneration
of retinal ganglion cells, signs of destructive changes in the retinal capillaries walls
were noted in animals of Group 2, and rEpo administration significantly reduced
the risk of development of those complications in Group 3.Актуальність. Останім часом ведуться дослідження про роль еритропоетину в розвитку та прогресуваггі діабетичної ретинопатії. Метою цього дослідження є визначення впливу рекомбінантного ЕПО у тварин з стрептозотоциновим діабетом на структурні особливості сітківки, а також концентрацію гемоглобіну та кількість ерітроцитіву периферичній крові. Матеріал і методи. Експеримент проведенийна30 щурах породи Вістар. Цукровий діабет моделювали за допомогою одноразового внутрішньочеревного введення стрептозотоцину в дозі 65 мг на 1 кг ваги. Всі щури розподілялися на три групи, по десять щурів (20 очей) у кожній групі. І группа – інтактні тварини, ІІ группа – тварини з модельованим діабетом, ІІІ – тварини з модельованим діабетом, что отримували рЕПО. Результати. У інтактних тварин в периферичній крові та скловидному тілі визначаеться еритропоетин.
Введення тваринам ІІІ групі рЕПО призводить до достовірного підвищення концентрації ЕПО в периферичній крові та скловидному тілі, збільшення кількості еритроцитів та
концентрації гемоглобіну. У тварин ІІ групи відзначається розвиток набряку сітківки, вакуольна дегенерація
гангліозних клітин сітківки, ознаки деструктивних змін стінок частини капілярів сітківки, а введення тваринам ІІІ групи рЕПО істотно зніжує ймовірність ціх змін
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