Static conductivity of charged domain wall in uniaxial ferroelectric-semiconductors

Using Landau-Ginzburg-Devonshire theory we calculated numerically the static conductivity of both inclined and counter domain walls in the uniaxial ferroelectrics-semiconductors of n-type. We used the effective mass approximation for the electron and holes density of states, which is valid at arbitrary distance from the domain wall. Due to the electrons accumulation, the static conductivity drastically increases at the inclined head-to-head wall by 1 order of magnitude for small incline angles theta pi/40 by up 3 orders of magnitude for the counter domain wall (theta=pi/2). Two separate regions of the space charge accumulation exist across an inclined tail-to-tail wall: the thin region in the immediate vicinity of the wall with accumulated mobile holes and the much wider region with ionized donors. The conductivity across the tail-to-tail wall is at least an order of magnitude smaller than the one of the head-to-head wall due to the low mobility of holes, which are improper carries. The results are in qualitative agreement with recent experimental data for LiNbO3 doped with MgO.Comment: 20 pages, 6 figures, 1 appendi

Domain wall conduction in multiaxial ferroelectrics

The conductance of domain wall structures consisting of either stripes or cylindrical domains in multi-axial ferroelectric-semiconductors is analyzed. The effects of the domain size, wall tilt and curvature, on charge accumulation, are analyzed using the Landau-Ginsburg Devonshire (LGD) theory for polarization combined with Poisson equation for charge distributions. Both the classical ferroelectric parameters including expansion coefficients in 2-4-6 Landau potential and gradient terms, as well as flexoelectric coupling, inhomogeneous elastic strains and electrostriction are included in the present analysis. Spatial distributions of the ionized donors, free electrons and holes were found self-consistently using the effective mass approximation for the respective densities of states. The proximity and size effect of the electron and donor accumulation/depletion by thin stripe domains and cylindrical nanodomains are revealed. In contrast to thick domain stripes and thicker cylindrical domains, in which the carrier accumulation (and so the static conductivity) sharply increases at the domain walls only, small nanodomains of radius less then 5-10 correlation length appeared conducting across entire cross-section. Implications of such conductive nanosized channels may be promising for nanoelectronics.Comment: 39 pages, 11 figures, 3 tables, 4 appendice

The 'Route from the Varangians to the Greeks': truth or fiction

The 'route from the Varangians to the Greeks' is widely known and often mentioned in research, popular science and educational literature. Much less often is it mentioned that the existence of the trade route is seriously doubted and needs additional evidence. The discussion about the actuality of a 'route from the Varangians to the Greeks' has intensified in the recent decade; it mostly involves historians who draw on chronicles, archive materials and literary sources. Although relevant geographical studies focus on small territories and have a limited scope, only they can give a definitive answer to the question of whether it was possible to sail the rivers of the East European Plain between the Baltic and Black Seas in the 8th-11th centuries AD. Of particular importance are studies on the watersheds marking the principal legs of the route. If the watersheds were traversable, the 'route from the Varangians to the Greeks' was navigable, and the impassability of watersheds would preclude navigation along the route. Methodologically, the study employs methods and approaches used in physiographical field studies, which have not been applied earlier to the watershed sections of the 'route from the Varangians to the Greeks'. The central result of the research is the reconstruction of the hydrological features and hydrographic situation of the watershed between the basins of the Neva (River Lovat) and the Western Dvina (River Usvyacha) during the existence of the 'route from the Varangians to the Greeks'. This reconstruction and the study of the watershed territories, the system of land communication routes and toponymic features of this territory conclusively demonstrate that the 'way from the Varangians to the Greeks', or the Baltic-Black Sea waterway, could actually exist

КОМБИНИРОВАННОЕ ЛЕЧЕНИЕ БОЛЬНЫХ НЕОПЕРАБЕЛЬНЫМИ МЕТАСТАЗАМИ КОЛОРЕКТАЛЬНОГО РАКА ПЕЧЕНИ

The purpose of the study was to improve treatment outcomes for patients with inoperable colorectal liver metastases using the  combination of chemoembilization of the hepatic artery and radiofrequency ablation.Material and methods. Treatment outcomes of 60 patients with methachronic unresectable liver metastases from colorectal cancer  were analyzed. Eligibility criteria were as follows: absence of  extrahepatic metastases, size of metastases from 3 to 5 cm, and  inability to perform resection. All patients were divided into two groups. Group I included 30 patients who received combination  of regional chemotherapy and radiofrequency ablation. Group II (the control group) consisted of 30 patients who received radiofrequency ablation only.Results. Post-embolization and post-ablation syndromes were observed in both groups of patients. Rightsided hydrothorax  (Clavien-Dindo grade II) was found in 4 out of 60 patients (2  patients in Group I and 2 patients in Group II). One-, two- and  three-year disease-free survival rates in Group I patients were 96.6  %, 76.6 % and 53.3 %, respectively. The corresponding rates in the  control group patients were 90.0 %, 53.6 % and 30.0 %,  respectively (p=0.049). The overall one-, two-and three-year  survival rates in Group I patients were 100 %, 90 % and 63.3 %,  respectively. The corresponding rates in the control group patients  were 100 %, 70 % and 50.0 %, respectively (p=0.202).Conclusion. The combination of regional chemotherapy and radiofrequency ablation led to the improvement in overall and disease-free survival rates.Цель исследования – улучшить результаты лечения больных с нерезектабельными метастазами колоректального рака печени путем комбинации химиоэмболизации  печеночной артерии и радиочастотной аблации.Материал и методы. Проанализированы результаты лечения 60 больных с метахронныминерезектабельными метастазами колоректального рака в печень. Критерии включения: отсутствие экстрапеченочных метастазов; размер метастазов от 3 до 5 см; невозможность  проведения резекционного вмешательства. Больные были разделены на основную группу  (30 пациентов), куда вошли те, кому проведена комбинация регионарной химиотерапии и  радиочастотной аблации, и контрольную группу (30 пациентов), в нее вошли больные, которым проведена радиочастотная аблация.Результаты. Постэмболизационный и постаблационный синдром был у всех больных основной и контрольной групп. Осложнения были у 4 из 60 больных (2 больных в основной  группе и 2 больных в контрольной группе (p=1)) – правосторонний гидроторакс (II класс по Clavien-Dindo). Безрецидивная выживаемость в основной группе за первый год составила 96,6 %, за второй – 76,6 %, за третий – 53,3 %. В контрольной группе – 90,0,  53,6 и 30,0 % соответственно (p=0,049). Общая одно-, двух- и трехлетняя выживаемость у  больных основной группы составила 100, 90 и 63,3 %. В контрольной группе – 100, 70 и 50,0 % соответственно (p=0,202).Заключение. Применение на практике комбинированного метода позволило улучшить  результаты лечения больных с нерезектабельными метастазами колоректального рака печени за счет увеличения общей и безрецидивной выживаемости

Genetics of Host Response to Leishmania tropica in Mice – Different Control of Skin Pathology, Chemokine Reaction, and Invasion into Spleen and Liver

Several hundred million people are exposed to the risk of leishmaniasis, a disease caused by intracellular protozoan parasites of several Leishmania species and transmitted by phlebotomine sand flies. In humans, L. tropica causes cutaneous form of leishmaniasis with painful and long-persisting lesions in the site of the insect bite, but the parasites can also penetrate to internal organs. The relationship between the host genes and development of the disease was demonstrated for numerous infectious diseases. However, the search for susceptibility genes in the human population could be a difficult task. In such cases, animal models may help to discover the role of different genes in interactions between the parasite and the host. Unfortunately, the literature contains only a few publications about the use of animals for L. tropica studies. Here, we report an animal model suitable for genetic, pathological and drug studies in L. tropica infection. We show how the host genotype influences different disease symptoms: skin lesions, parasite dissemination to the lymph nodes, spleen and liver, and increase of levels of chemokines CCL2, CCL3 and CCL5 in serum

Distinct genetic control of parasite elimination, dissemination, and disease after Leishmania major infection

Elimination of pathogens is the basis of host resistance to infections; however, relationship between persisting pathogens and disease has not been clarified. Leishmania major infection in mice is an important model of host–pathogen relationship. Infected BALB/c mice exhibit high parasite numbers in lymph nodes and spleens, and a chronic disease with skin lesions, splenomegaly, and hepatomegaly, increased serum IgE levels and cytokine imbalance. Although numerous gene loci affecting these disease symptoms have been reported, genes controlling parasites’ elimination or dissemination have never been mapped. We therefore compared genetics of the clinical and immunologic symptomatology with parasite load in (BALB/c × CcS-11) F2 hybrids and mapped five loci, two of which control parasite elimination or dissemination. Lmr5 influences parasite loads in spleens (and skin lesions, splenomegaly, and serum IgE, IL-4, and IFNγ levels), and Lmr20 determines parasite numbers in draining lymph nodes (and serum levels of IgE and IFNγ), but no skin or visceral pathology. Three additional loci do not affect parasite numbers but influence significantly the disease phenotype—Lmr21: skin lesions and IFNγ levels, Lmr22: IL-4 levels, Lmr23: IFNγ levels, indicating that development of L. major-caused disease includes critical regulations additional to control of parasite spread

Периоперационная химиотерапия в лечении местно-распространенных форм рака ободочной кишки: обзор литературы

Neoadjuvant systemic therapy is standard of care for many tumors, especially of gastrointestinal ones. Neoadjuvant therapy has many potential advantages, including tumor downstaging, early treatment of micrometastatic disease and possibility to evaluate tumor biology in order to personalize treatment. Currently, perioperative chemotherapy isn’t the standard of treatment of advanced colon cancer. Limitations to widespread use of systemic therapy have included inaccurate radiological staging, concerns about tumor progression and a lack of randomized data.Неоадъювантная химиотерапия является стандартом лечения многих опухолей, в особенности желудочно-кишечного тракта. Данный подход имеет много потенциальных преимуществ, включая регресс опухоли, раннее начало лечения микрометастазов, а также возможность оценивать биологию опухоли, тем самым персонализируя подход к лечению. В настоящее время неоадъювантная химиотерапия не является стандартом лечения местно-распространенного рака ободочной кишки, что связано с неточностью предоперационного стадирования, возможностью прогрессирования опухоли, а также отсутствием достаточного количества рандомизированных клинических исследований

Диагностическая значимость ICG-картирования сторожевых лимфоузлов у больных раком эндометрия I стадии

Background. Lymphatic spread is the main route of metastasis in early stage endometrial cancer. Considering its significance, three risk factors of lymph node metastasis were identified. At a high risk of lymph node metastasis in patients with stage I endometrial cancer, pelvic and lumbar lymph node dissection is recommended. In low-risk patients, lymph node dissection is not performed. Lymph node dissection in medium-risk patients is considered as a staging procedure. However, in patients with aggravating factors that prevent extended hysterectomy, lymph node biopsy with ICG mapping and subsequent microstaging may be an alternative to lymph node dissection. Purpose of the study: to analyze the effectiveness of surgical approaches for staging endometrial cancer at different risk factors for lymphatic metastasis.Material and Methods. The treatment outcomes were retrospectively analyzed in 565 patients with stage I endometrial cancer treated at the gynecological oncology department of Botkin City Clinical Hospital and at the gynecological oncology department of Kaluga Regional Clinical Oncology Center from 2021 to 2023. All women were divided into three groups according to the risk factors of lymph node metastasis. Patients underwent hysterectomy, hysterectomy combined with pelvic or pelvic and lumbar lymphadenectomy, as well as hysterectomy with ICG mapping and sentinel lymph node biopsy.Results. A total of 334 endometrial cancer patients underwent surgery at Botkin City Clinical Hospital. In the medium-risk group patients (n=94), who underwent hysterectomy with pelvic (n=36) and pelvic + lumbar lymphadenectomy (n=31), lymph node metastases were detected in 4 (11.1 %) and 6 (19.4 %) patients, respectively. In the high-risk group (n=50) with similar surgeries, metastatic lymph nodes were identified in 2 (10.5 %, n=19) and 6 (26.1 %, n=23) patients, respectively. At Kaluga Regional Oncology Center, 231 patients underwent hysterectomy with sentinel lymph node biopsy. The low-risk group, the medium-risk group, and the high-risk group showed lymph node metastases in 7 (5.47 %), 6 (10.2 %), and 6 (13.6 %) patients, respectively.Conclusion. In stage I endometrial cancer patients with a low risk of lymph node metastasis, hysterectomy with sentinel lymph node biopsy is recommended. For medium-and high-risk groups, hysterectomy with systemic lymphadenectomy is recommended. If it is not possible to remove the pelvic and lumbar lymph nodes, their biopsy with ICG mapping and microstaging can be recommended. A combination of systemic lymphadenectomy with sentinel lymph node biopsy is a promising technique that could hypothetically demonstrate better results in terms of disease staging.Введение. Лимфогенный путь метастазирования является преимущественным при начальных стадиях рака эндометрия. Учитывая его значимость, выделены три степени риска лимфогенного метастазирования. При высокой степени риска пациенткам с I стадией заболевания рекомендуется лимфаденэктомия тазовых и поясничных лимфоузлов, при низкой – удаление лимфатических узлов не проводят. Лимфаденэктомию лимфоузлов при промежуточной степени риска метастазирования позиционируют как стадирующую процедуру. Однако при наличии отягощающих факторов, препятствующих проведению расширенной гистерэктомии, альтернативным методом может быть биопсия сторожевых лимфоузлов с ICG-картированием и последующим микростадированием.Цель исследования – проанализировать эффективность хирургических подходов для стадирования рака эндометрия при различных степенях риска лимфогенного метастазирования.Материал и методы. Ретроспективно проанализированы результаты лечения 565 больных раком эндометрия I стадии в онкогинекологическом отделении Городской клинической больницы им. С.П. Боткина и онкогинекологическом отделении Калужского областного клинического онкологического диспансера с 2021 по 2023 г. Все женщины были разделены на три группы в зависимости от степени риска лимфогенного метастазирования. Пациенткам выполнены гистерэктомия, гистерэктомия в сочетании с тазовой или с тазовой и поясничной лимфаденэктомией, а также гистерэктомия с ICG-картированием и биопсией сторожевых лимфоузлов. Результаты. В онкогинекологическом отделении Городской клинической больницы им. С.П. Боткина было прооперировано 334 женщины. У пациенток с промежуточной степенью риска (n=94) после гистерэктомии с тазовой и с тазовой (n=36) и поясничной лимфаденэктомией (n=31) выявлено 4 (11,1 %) и 6 (19,4 %) случаев пораженных лимфоузлов соответственно. В группе высокого риска (n=50) после аналогичных операций патологические лимфоузлы обнаружены у 2 (10,5 %, n=19) и 6 (26,1 %, n=23) пациенток. В Калужском областном диспансере прооперирована 231 пациентка; всем выполнена гистерэктомия с биопсией сторожевых лимфоузлов. При низкой степени риска выявлено 7 (5,47 %) случаев поражения узлов, при промежуточной – 6 (10,2 %), при высокой степени риска метастазирования – 6 (13,6 %) случаев злокачественных клеток в лимфоузлах.Заключение. У больных раком эндометрия I стадии с низкой степенью риска лимфогенного метастазирования целесообразно выполнять гистерэктомию с биопсией сторожевых лимфоузлов. При промежуточной и высокой степени риска рекомендуется гистерэктомия с системной лимфаденэктомией. При отсутствии возможности удаления тазовых и поясничных лимфатических узлов можно рекомендовать их биопсию с ICG-картированием и микростадированием. Перспективным направлением может явиться сочетание системной лимфаденэктомии с биопсией сторожевых лимфоузлов, которые гипотетически могут продемонстрировать лучшие результаты с позиции стадирования заболевания