A theory of MHD instability of an inhomogeneous plasma jet

A problem of the instability of an inhomogeneous axisymmetric plasma jet in a parallel magnetic field is solved. The jet boundary becomes, under certain conditions, unstable relative to magnetosonic oscillations (Kelvin-Helmholtz instability) in the presence of a shear flow at the jet boundary. Because of its internal inhomogeneity the plasma jet has resonance surfaces, where conversion takes place between various modes of plasma MHD oscillations. Propagating in inhomogeneous plasma, fast magnetosonic waves drive the Alfven and slow magnetosonic oscillations, tightly localized across the magnetic shells, on the resonance surfaces. MHD oscillation energy is absorbed in the neighbourhood of these resonance surfaces. The resonance surfaces disappear for the eigen-modes of slow magnetosonic waves propagating in the jet waveguide. The stability of the plasma MHD flow is determined by competition between the mechanisms of shear flow instability on the boundary and wave energy dissipation because of resonant MHD-mode coupling. The problem is solved analytically, in the WKB approximation, for the plasma jet with a boundary in the form of a tangential discontinuity over the radial coordinate. The Kelvin-Helmholtz instability develops if plasma flow velocity in the jet exceeds the maximum Alfven speed at the boundary. The stability of the plasma jet with a smooth boundary layer is investigated numerically for the basic modes of MHD oscillations, to which the WKB approximation is inapplicable. A new "global" unstable mode of MHD oscillations has been discovered which, unlike the Kelvin-Helmholtz instability, exists for any, however weak, plasma flow velocities

Power-law scaling in dimension-to-biomass relationship of fish schools

Motivated by the finding that there is some biological universality in the relationship between school geometry and school biomass of various pelagic fishes in various conditions, I here establish a scaling law for school dimensions: the school diameter increases as a power-law function of school biomass. The power-law exponent is extracted through the data collapse, and is close to 3/5. This value of the exponent implies that the mean packing density decreases as the school biomass increases, and the packing structure displays a mass-fractal dimension of 5/3. By exploiting an analogy between school geometry and polymer chain statistics, I examine the behavioral algorithm governing the swollen conformation of large-sized schools of pelagics, and I explain the value of the exponent.Comment: 25 pages, 6 figures, to appear in J. Theor. Bio

ПУТИ СНИЖЕНИЯ ИНФУЗИОННОЙ НАГРУЗКИ У ДЕТЕЙ С ОБШИРНЫМИ ОЖОГАМИ В ПЕРВЫЕ 24 ЧАСА ПОСЛЕ ПОВРЕЖДЕНИЯ

The study was conducted with the purpose to optimize the management activities during first hours after burn injury. The prospective, open, randomized, comparative study included 50 children with severe burns demonstrated the safe reduction of fluid volume combined with the early enteral load. It was shown that early use of albumin in children with burns exceeding 20% of total body surface area allowed decreasing the need in crystalloid solutions when compiling infusion therapy regimen. That regimen allowed avoiding fluid overloading and development of the edema syndrome. Проведено исследование, направленное на оптимизацию комплекса мер интенсивной терапии в первые часы после ожогового повреждения. В проспективном, открытом, рандомизированном сравнительном исследовании у 50 детей с обширными ожогами продемонстрировано безопасное снижение объемов инфузионной терапии в сочетании с ранней энтеральной нагрузкой. Показана возможность раннего применения альбумина у детей с ожогами более 20% общей площади поверхности тела, что позволяет снизить потребность в кристаллоидных растворах при составлении схемы инфузионной терапии. Данная схема позволяет избежать перегрузки жидкостью и развития отечного синдрома.

MicroRNA-34, microRNA-130, microRNA-148, microRNA-181, microRNA-194 and microRNA-605 expression in colon cancer tissue

Purpose of the study. Determination of the expression of microRNA‑34, microRNA‑130, microRNA‑148, microRNA‑181, microRNA‑194 and microRNA‑605 in colon tumor tissue depending on the clinical and morphological features of the tumor and the effectiveness of treatment.Materials and methods. The study included 56 patients diagnosed with colorectal cancer aged 43 to 75 years with the average age of 54 years. Taking into account the local prevalence of the process patients received surgical or combined treatment, including neoadjuvant chemotherapy, in the clinics of the Cancer Research Institute, Tomsk NRMC. MicroRNA expression was determined by polymerase chain reaction (PCR) in real time.Results. The obtained information revealed the relation of microRNA‑130 to the tumor size. The development of regional metastases was associated with changes in microRNA‑130, microRNA‑194 and microRNA‑605. The level of histological organization of the tumor was associated with microRNA‑34, microRNA‑130, microRNA‑148, and the response to therapy – with microRNA‑130, microRNA‑148 and microRNA‑605. In addition, according to the study, the significance of microRNA‑130 was revealed, which is associated with tumor spread, histological differentiation and response to antitumor therapy.Conclusion. The features of expression of microRNA‑34, microRNA‑130, microRNA‑148, microRNA‑181, microRNA‑194 and microRNA‑605 associated with clinical and morphological features of colon tumors were revealed. Correlations between the studied indicators are noted, which probably determine the outcome and prognosis of the disease

Successful surgical treatment of metachronous carcinoma of the appulla of Vater and ductal carcinoma of the distal parts of the pancreas: A case report

Background. Currently, there is a steady trend towards an increase in the incidence of both synchronous and metachronous multiple primary malignant tumors (MPMT). However, metachronous polyneoplasia of the pancreatobiliary tract is relatively rare, and there have been very few reports on successful treatment of this malignancy. Case presentation. In September 2014, the patient K. was diagnosed with adenocarcinoma of the ampulla of Vater (T2N0M0, stage Ib) and underwent gastropancreatoduodenal resection with the creation of pancreatic-gastric anastomosis at the Abdominal Department of Cancer Research Institute of Tomsk National Research Medical Center. There were no complications in the postoperative period. At a 6.5-year followup, no evidence of disease progression was found. In April 2021, a follow-up examination conducted at the Cancer Research Institute revealed a large lesion on the distal part of the pancreatic stump with no clinically significant manifestations. Diagnosis of MPMT was confirmed by transgastric endoscopic ultrasound-guided biopsy. Histological and immunohistochemical examinations revealed undifferentiated ductal carcinoma of the pancreas. Considering the metachronous tumor localization, pancreatic stump extirpation with resection of the posterior wall of the stomach and splenectomy was performed. No complications occurred in the postoperative period. The patient received replacement therapy for exocrine pancreatic insufficiency and individual correction of carbohydrate metabolism. At a 15-month follow-up, liver metastases were detected, and palliative chemotherapy was administered. The patient died 6 months later due to disease progression. The survival time was 99 months after the first surgery and 21 months after the second surgery. Conclusion. We report a rare case of metachronous cancers of the ampulla of Vater and pancreatic stump developed with an interval of 6.5 years. The patient underwent successful curative resections consecutively. The overall survival time from the date of diagnosis was 99 months

Multimodal therapy for metastatic colorectal cancer: a case of complete clinical and radiological response of liver metastases

Background. Colorectal cancer is one of the most common cancers and the second leading cause of cancer-related deaths worldwide. Population-based studies have shown that 25–30 % of patients with colorectal cancer have synchronous liver metastases at the time of diagnosis. despite modern advances in oncology and surgery, only 25 % of patients with metastatic colorectal cancer (mCRC) are suitable for liver resection, which is the only curative treatment option for these patients. In recent years, the indications for curative treatment of mCRC have expanded. due to the introduction of new targeted drugs into clinical practice, the tumor response rate to preoperative therapy has increased, thus increasing surgical resection rate. Some patients experience a complete clinical response, which is defined as the complete disappearance of liver metastases. However, 30–70 % of patients develop recurrent metastases in the liver within the first year of follow-up, and currently, even in the presence of complete regression of metastases, it is recommended to perform resection of the initially affected hepatic segments. Case presentation. We describe a case of complete clinical and radiological response of liver metastases after chemotherapy in a patient with sigmoid colon cancer. Molecular genetic analysis revealed the wild type of the Kras, Nras and Braf genes. The patient received 3 courses of preoperative chemotherapy according to the FOLFOxIRI + Cetuximab regimen. Laparoscopic sigmoid colon resection with d3 lymph node dissection was followed by adjuvant chemotherapy with oxaliplatin and 5-fluorouracil (12 cycles). After 16 months of follow-up, no evidence of colon cancer recurrence and liver metastasis was found. Conclusion. Current targeted therapy has demonstrated efficacy in treating mCRC with synchronous liver metastases and makes it possible, in selected cases, to avoid the liver resection provided that a complete clinical and radiological response of the metastases is achieved

Benthic harpacticoid copepods of the Yenisei Gulf and the adjacent shallow waters of the Kara Sea

Garlitska, L.A., Azovsky, A.I. (2016): Benthic harpacticoid copepods of the Yenisei Gulf and the adjacent shallow waters of the Kara Sea. Journal of Natural History 50: 2941-2959, DOI: 10.1080/00222933.2016.1219410, URL: http://dx.doi.org/10.1080/00222933.2016.121941

Microbenthos of subarctic intertidal beaches with different morphodynamics

Diversity and composition of benthic diatom algae and ciliates were studied at several beaches along the White and Barents seas, from highly exposed, reflective beaches with coarse-grained sands to sheltered, dissipative silty-sandy flats. The data set adresses the objective to estimate the possible influence of the morphodynamic state and/or the sediment properties on the microbenthos (diatom algae and ciliates) of various high-latitude sandy beaches from the White and Barents Sea coasts