A Comparison of the Elemental Concentrations in Tissue Thymocytes from Diabetic and Non-Diabetic Rats

The elemental concentrations in thymocytes from control and diabetic rats were studied by use of the techniques of cryofixation and X-ray microanalysis to determine whether any changes occur in the diseased state. Decreases in the concentrations of the elements P and K were found in thymocytes from the subcapsular and cortical regions of the gland in thymus tissue taken 4 days after the onset of diabetes. A decrease in the concentration of Mg was also found in thymocytes from the subcapsular region of the gland. These changes suggest that the metabolism of thymocytes in vivo is altered in the diabetic animals

X-Ray Microanalysis of Cells in Suspension and the Application of this Technique to the Study of the Thymus Gland

Although X-ray microanalysis has become a well established technique in the study of tissues there are still relatively few papers reporting results from cells in culture. Our early investigations on freshly isolated murine thymocytes reported higher than expected concentrations of Na and Cl in these cells but subsequent studies have shown that these high concentrations are artefactual. Rat thymocytes that have been isolated and incubated for a short time to allow them to recover from the isolation procedure have lower concentrations of Na and Cl. Sections prepared from pellets of cells which have been concentrated by centrifugation in a microhaematocrit centrifuge have concentrations of Na and Cl which are within the range that has been described for thymocytes in tissues. This method of concentration can be applied successfully to the study of white cells from the peripheral blood. In diabetic animals pyknotic cells occur in the thymus. These cells are characterised by low concentrations of K but no rise in the concentration of Na. Study of thymocytes isolated from a diabetic animal also show pyknotic cells low in K confirming these observations

Letter to Philander Chase

Miss Warley informs Philander Chase of the death of Colonel Richardson.https://digital.kenyon.edu/chase_letters/2160/thumbnail.jp

From Hela Cell Division to Infectious Diarrhoea

Hela 83 cells were grown in suspension both randomly and, synchronously using hydroxyurea which blocks cells at the Gl/8 interface. Cryosections were prepared, freeze-dried and analyzed by X-ray microanalysis. As cells moved into S and through M phases [Na] and [Cl] increased; both returned to normal levels upon re-entering Gl phase. The Na/K ratio was 1:1 in Gl phase. Infection of HeLa 83 cells in Gl phase with vaccinia virus resulted in no change in intracellular [Na]. Infection of neonatal mice with murine rotavirus was localized to villus tip enterocytes and gave rise to diarrhoea which was maximal at 72h post-infection (p.i.). Diarrhoea was preceded by ischemia of villi (18-42h p.i.) and villus shortening (maximal at 42h p.i.), and was also coincident with a dramatic regrowth of villi. At 48h p.i. a proliferative zone of electron lucent cells was observed in villus base regions. Cryosections of infected gut, taken before, during, and after infection, together with corresponding age-matched controls, were freeze-dried and analysed by X-ray microanalysis. At 48h p.i. electron lucent villus base cells were shown to be more hydrated, and, to contain higher levels of both Na and Cl and lower levels of P, S, K and Mg than corresponding control cells. These studies (we argue) increase confidence in the use of X-ray microanalysis in studying biological systems, provide some insight into the process of cell division, and constitute the basis of a new concept of diarrhoeal secretion

Problems Associated with the Preparation of Cell Suspensions for X-Ray Microanalysis Highlighted by the Comparison of Results with Those Obtained from Tissue Sections

Fully quantitative X-ray microanalysis of freeze dried frozen sections allowed the concentration of monovalent ions in the nuclei of mouse thymocytes in tissue sections to be compared with those from thymocytes which had been isolated by a simple preparation procedure. Isolated cells showed increased concentrations of Na and Cl. This was further investigated in the rat where the size of the thymus a 11 owed comparison between different isolation media using cells derived from the same animal. Use of autologous serum as the final suspending medium gave reproducible results, whereas with suspension in BSS, or 20% dextran the results were more variable. When the results obtained for the cells isolated in serum were compared with values for tissue thymocytes elevated levels of Na and Cl were still apparent although these were not as great as the differences recorded for the mouse. The effect of the drop in temperature which occurs during the isolation procedure could not account for the observed differences

Correction to: Wnt3a induces exosome secretion from primary cultured rat microglia

Correction to: BMC Neuroscience 2012, 13:144 http://www.biomedcentral.com/1471-2202/13/14

Indução floral de beterraba por meio de vernalização artificial das raízes nas condições de Brasília / Table beet floral induction by artificial vernalization of roots under Brasília conditions

Beet is a biennial plant with requirement of exposure to low temperatures and long photoperiods. This species usually does not flower naturally in most parts of Brazil, including Brasília conditions of temperature and day length. Thus, the treatment duration in cold storage should be quantified to evaluate the feasibility of producing beet seed from artificially vernalized roots. The aim of this study was to determine the optimal period of cold treatment of tablebeet through artificial vernalization to flower plants under Brasilia conditions. Different durations of exposure to cold (5°C) were evaluated: 0, 30, 60 and 90 days.Roots of ‘Itapuã 202’ beet produced internally at Embrapa Vegetables were used. After this period, the roots were transplanted to the field. The low flowering rate (ranging from 31% to 54%) suggests the non feasibility of commercial use of artificial vernalization to floral induction of ‘Itapuã 202’ beet in Brasília conditions.   RESUMO A beterraba é uma planta bianual que requer exposição a temperaturas baixas e a fotoperíodos longos para indução do florescimento. Esta espécie, em geral, não floresce naturalmente na maioria das regiões brasileiras, incluindo as condições de temperatura e comprimento do dia de Brasília. Assim, a duração da exposição a temperaturas baixas em câmaras frigoríficas deve ser quantificada para avaliar a viabilidade de se produzir sementes de beterraba por meio da vernalização artificial das raízes. O objetivo deste trabalho foi determinar o período ideal do tratamento térmico de raízes de beterraba por meio da vernalização artificial visando ao florescimento das plantas nas condições de Brasília. Foram avaliados diferentes períodos de exposição ao frio (5°C): 0, 30, 60 e 90 dias, utilizando raízes da cultivar Itapuã 202 produzidas na Embrapa Hortaliças. Após esse período, as raízes foram levadas para o campo. A baixa porcentagem de florescimento (variando de 31 a 54%) obtida sugere a inviabilidade comercial do uso da vernalização artificial de raízes de beterraba para indução floral da cultivar Itapuã 202 nas condições de Brasília.A beterraba é uma planta bianual que requer exposição a temperaturas baixas e a fotoperíodos longos para indução do florescimento. Esta espécie, em geral, não floresce naturalmente na maioria das regiões brasileiras, incluindo as condições de temperatura e comprimento do dia de Brasília. Assim, a duração da exposição a temperaturas baixas em câmaras frigoríficas deve ser quantificada para avaliar a viabilidade de se produzir sementes de beterraba por meio da vernalização artificial das raízes. O objetivo deste trabalho foi determinar o período ideal do tratamento térmico de raízes de beterraba por meio da vernalização artificial visando ao florescimento das plantas nas condições de Brasília. Foram avaliados diferentes períodos de exposição ao frio (5°C): 0, 30, 60 e 90 dias, utilizando raízes da cultivar Itapuã 202 produzidas na Embrapa Hortaliças. Após esse período, as raízes foram levadas para o campo. A baixa porcentagem de florescimento (variando de 31 a 54%) obtida sugere a inviabilidade comercial do uso da vernalização artificial de raízes de beterraba para indução floral da cultivar Itapuã 202 nas condições de Brasília.   ABSTRACT Beet is a biennial plant with requirement of exposure to low temperatures and long photoperiods. This species usually does not flower naturally in most parts of Brazil, including Brasília conditions of temperature and day length. Thus, the treatment duration in cold storage should be quantified to evaluate the feasibility of producing beet seed from artificially vernalized roots. The aim of this study was to determine the optimal period of cold treatment of tablebeet through artificial vernalization to flower plants under Brasilia conditions. Different durations of exposure to cold (5°C) were evaluated: 0, 30, 60 and 90 days.Roots of ‘Itapuã 202’ beet produced internally at Embrapa Vegetables were used. After this period, the roots were transplanted to the field. The low flowering rate (ranging from 31% to 54%) suggests the non feasibility of commercial use of artificial vernalization to floral induction of ‘Itapuã 202’ beet in Brasília conditions

CONTROLADOR LÓGICO PROGRAMÁVEL UTILIZANDO PIC 18F4550

Desde a criação dos relés eletromecânicos os processos industriais vêm se modernizando, principalmente após a descoberta dos microprocessadores que impulsionaram o desenvolvimento dos controladores lógicos programáveis. Os controladores tornaram os processos produtivos flexíveis do ponto de vista de manutenção, expansão e principalmente aumentando a qualidade dos produtos e qualidade de vida dos envolvidos, já que esta tecnologia vem retirando os homens de processos insalubres e tornando estes processos inteligentes e independentes. A cada dia os controladores ficam mais poderosos e consequentemente mais caros, o que vem tornando estes dispositivos inviáveis para processos simples e com baixo valor agregado. Este fato motivou o desenvolvimento de um controlador de baixo custo de produção e de fácil implementação para profissionais que atuam nestes processos mais simples. Para o desenvolvimento deste trabalho foi utilizado o Microcontrolador PIC18F4550. Depois de concluídas as simulações foi observada a possibilidade de se aumentar os módulos de entrada e saída do controlador, o que torna seu custo beneficio ainda maior

Mobility Strategy of Multi-Limbed Climbing Robots for Asteroid Exploration

Mobility on asteroids by multi-limbed climbing robots is expected to achieve our exploration goals in such challenging environments. We propose a mobility strategy to improve the locomotion safety of climbing robots in such harsh environments that picture extremely low gravity and highly uneven terrain. Our method plans the gait by decoupling the base and limbs' movements and adjusting the main body pose to avoid ground collisions. The proposed approach includes a motion planning that reduces the reactions generated by the robot's movement by optimizing the swinging trajectory and distributing the momentum. Lower motion reactions decrease the pulling forces on the grippers, avoiding the slippage and flotation of the robot. Dynamic simulations and experiments demonstrate that the proposed method could improve the robot's mobility on the surface of asteroids.Comment: Submitted version of paper accepted for presentation at the CLAWAR 2023 (26th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines