119 research outputs found
Wood anatomical features of growth rings of tree species from semi-deciduous forest in Southern Brazil.
Espécies com potencial para estudos em dendrocronologia em uma Floresta Estacional Semidecidual no Sul do Brasil.
Padrões de crescimento radial do tronco de Alchornea glandulosa Poit. & Baill (Euphobiaceae), Aspidosperma polyneuron Müll. Arg. (Apocynaceae) e Trichilia claussenii C. DC (Meliaceae).
Liquid Foam-Ethyl Vinyl Acetate Adhesive Systems for Lining Process of Paintings: Prospects of a User-Friendly, Harmless Alternative to Conventional Products
The lining of paintings is a process of conservation science and art restoration used to strengthen, flatten, or consolidate paintings on canvas by attaching by means of adhesives a second canvas to the back of the existing one. To this aim, the prospects of the use of ethyl vinyl acetate (EVA) resins in aqueous dispersion applied as an adhesive in a foam form have been investigated in the present study. The key physical properties of the foam have been investigated, with a deep focus on rheological behavior and the drying rate, comparing the results with those obtained using the liquid products that are commercially available. Dedicated mock-ups have been prepared to test the adhesive for the lining process, inspecting adhesion strength, colorimetric properties, and the influence on the possible chromatic and visual alteration of the surface, also looking at the chemical interaction with painting materials and the deterioration after an artificial ageing process. The results obtained clearly indicated that the proposed technology is very suitable for the targeted application, and an EVA water-based foamed dispersion can be used for paintings' lining, in view of the ease of application, being an appropriate adhesion, no chemical interaction, nor the deterioration of the painting
Periodicidade do crescimento de espécies arbóreas da Floresta Estacional Semidecidual no Sul do Brasil.
Embora a sazonalidade climática seja menos evidente nas regiões tropicais que nas temperadas, muitas espécies tropicais apresentam crescimento rítmico. A avaliação do crescimento em circunferência do tronco (CCT) permitirá obter informações sobre o desenvolvimento dos indivíduos de espécies arbóreas desta região. Esse estudo teve como objetivo avaliar o CCT de 11 espécies arbóreas de uma floresta estacional semidecidual no sul do Brasil, visando testar duas hipóteses: (i) existe sazonalidade no CCT das árvores e este crescimento está relacionado às variações climáticas da região de estudo; (ii) as características dos indivíduos (posição sociológica, altura da árvore, grau de ocupação por lianas, deciduidade e diâmetro à altura do peito) influenciam no incremento acumulado em circunferência. Para detectar a periodicidade do CCT foram implantadas faixas dendrométricas permanentes no tronco (altura do DAP) de 156 indivíduos. O acompanhamento do crescimento foi realizado mensalmente por um período de 18 meses. Foram feitas correlações do CCT mensal com a precipitação, temperatura e fotoperíodo para verificar a influencia dos fatores ambientais e análise de covariância para averiguar se as características dos indivíduos também interferiram no incremento acumulado em circunferência do tronco. As espécies apresentaram um padrão sazonal de CCT, com as maiores taxas de crescimento de outubro a dezembro, sendo que os parâmetros ambientais avaliados atuaram em conjunto - principalmente o fotoperíodo e a temperatura - promovendo essa sazonalidade e confirmando a primeira hipótese. Considerando as características dos indivíduos, somente o diâmetro do tronco correlacionou-se negativamente com o incremento acumulado em circunferência (b = -0,32; p = 0,02), aceitando parcialmente a segunda hipótese
In vitro irradiation system for radiobiological experiments
Background: Although two-dimensional (2-D) monolayer cell cultures provide important information on basic tumor biology and radiobiology, they are not representative of the complexity of three-dimensional (3-D) solid tumors. In particular, new models reproducing clinical conditions as closely as possible are needed for radiobiological studies to provide information that can be translated from bench to bedside.
Methods: We developed a novel system for the irradiation, under sterile conditions, of 3-D tumor spheroids, the in vitro model considered as a bridge between the complex architectural organization of in vivo tumors and the very simple one of in vitro monolayer cell cultures. The system exploits the same equipment as that used for patient treatments, without the need for dedicated and highly expensive instruments. To mimic the passage of radiation beams through human tissues before they reach the target tumor mass, 96-multiwell plates containing the multicellular
tumor spheroids (MCTS) are inserted into a custom-built phantom made of plexiglass, the material most similar to water, the main component of human tissue.
Results: The system was used to irradiate CAEP- and A549-derived MCTS, pre-treated or not with 20 \u3bcM cisplatin, with a dose of 20 Gy delivered in one session. We also tested the same treatment schemes on monolayer CAEP and A549 cells. Our preliminary results indicated a significant increment in radiotoxicity 20 days after the end of
irradiation in the CAEP spheroids pre-treated with cisplatin compared to those treated with cisplatin or irradiation alone. Conversely, the effect of the radio- chemotherapy combination in A549-derived MCTS was similar to that induced by cisplatin or irradiation alone. Finally, the 20 Gy dose did not affect cell survival in monolayer CAEP and A549 cells, whereas cisplatin or cisplatin plus radiation caused 100% cell death, regardless of the type of cell line used.
Conclusions: We set up a system for the irradiation, under sterile conditions, of tumor cells grown in 3-D which allows for the use of the same dose intensities and schedules utilized in clinical practice. This irradiation system, coupled with 3-D cell cultures, has the potential to generate information that could be used to individually tailor radiotherap
Amelanotic/hypomelanotic lentigo maligna: Dermoscopic and confocal features predicting diagnosis
Background: Amelanotic/hypomelanotic lentigo maligna and lentigo maligna melanoma (AHLM/LMM) may be very difficult to diagnose at an early stage. Objectives: To quantify the predictive value of dermoscopic and reflectance confocal microscopy (RCM) features for AHLM/LMM. Methods: Dermoscopic and RCM images of histopathologically diagnosed AHLM/LMM, amelanotic/hypomelanotic benign lesions (AHBL), and amelanotic/hypomelanotic basal and squamous cell carcinomas (AHBCC/AHSCC) of the head and neck from consecutive patients were retrospectively collected and blindly evaluated by three observers to assess presence or absence of dermoscopic and RCM criteria. Results: Overall, 224 lesions in 216 patients including LM/LMM (n = 55, 24.6%), AHBL (n = 107, 47.8%) and AHBCC/AHSCC (n = 62, 27.7%) were analysed. Multivariable analysis showed that milky-red areas (OR = 5.46; 95% CI: 1.51–19.75), peripheral light brown structureless areas (OR = 19.10; 4.45–81.96), linear irregular vessels (OR = 5.44; 1.45–20.40), and asymmetric pigmented follicles (OR = 14.45; 2.77–75.44) at dermoscopy, and ≥3 atypical cells in five fields (OR = 10.12; 3.00–34.12) and focal follicular localization of atypical cells at dermo-epidermal junction (DEJ) (OR = 10.48; 1.10–99.81) at RCM were significantly independent diagnostic factors for AHLM/LMM vs. AHBL. In comparison with AHBCC/AHSCC, peripheral light brown structureless area (OR = 7.11; 1.53–32.96), pseudonetwork around hair follicles (OR = 16.69; 2.73–102.07), and annular granular structures (OR = 42.36; 3.51–511.16) at dermoscopy and large dendritic (OR = 6.86; 3.15–38.28) and round pagetoid cells (OR = 26.78; 3.15–227.98) at RCM led to a significantly increased risk of diagnosing AHLM/LMM. Conclusions: Amelanotic/hypomelanotic lentigo maligna and lentigo maligna melanoma may have the same dermoscopic features of AHM on other body sites, such as milky red areas, peripheral light brown structureless areas and linear irregular vessels. These features, asymmetric pigmented follicles and at RCM ≥ 3 atypical cells in five fields and focal follicular extension of atypical cells at DEJ may help in recognizing AHLM/LMM even when LM conventional features (e.g., obliteration of hair follicles under dermoscopy and large pagetoid cells under RCM) are absent or present only in very small areas of the lesion
Molecular, anatomical and physiological properties of a genetically modified soybean line transformed with rd29A:AtDREB1A for the improvement of drought tolerance.
We evaluated the molecular, anatomical and physiological properties of a soybean line transformed to improve drought tolerance with an rd29A:AtDREB1A construct. This construct expressed dehydration- responsive element binding protein DREB1A from the stress-inducible rd29A promoter. The greenhouse growth test included four randomized blocks of soybean plants, with each treatment performed in triplicate. Seeds from the non-transformed soybean cultivar BR16 and from the genetically modified soybean P58 line (T2 generation) were grown at 15% gravimetric humidity for 31 days. To induce water deficit, the humidity was reduced to 5% gravimetric humidity (moderate stress) for 29 days and then to 2.5% gravimetric humidity (severe stress). AtDREB1A gene expression was higher in the genetically modified P58 plants during water deficit, demonstrating transgene stability in T2 generations and induction of the rd29A promoter. Drought-response genes, including GmPI-PLC, GmSTP, GmGRP, and GmLEA14, were highly expressed in plants submitted to severe stress. Genetically modified plants had higher stomatal conductance and consequently higher photosynthetic and transpiration rates. In addition, they had more chlorophyll. Overexpression of AtDREB1A may contribute to a decrease in leaf thickness; however, a thicker abaxial epidermis was observed. Overexpression of AtDREB1A in soybean appears to enhance drought tolerance
Composição e diversidade de Scarabaeoidea (Coleoptera) atraídos por armadilha de luz em área rural no norte do Paraná, Brasil
Tumour microvessel density as predictor of chemotherapy response in breast cancer patients
The aim of this study was to evaluate the predictive value of intratumoural microvessel density in breast cancer. We studied immunohistochemically primary tumours of 104 patients with metastasised breast cancer who took part in a randomised multicentre trial comparing docetaxel to sequential methotrexate and 5-fluorouracil. Vessels were highlighted with factor VIII staining and counted microscopically. Microvessel density was compared with clinical response to chemotherapy and patient survival. The microvessel density of the primary tumour was not significantly associated with patient's response to chemotherapy, time to progression or overall survival in the whole patient population or in the docetaxel or methotrexate and 5-fluorouracil groups. However, disease-free survival was longer in patients with low microvessel density (P=0.01). These findings suggest that microvessel density of the primary tumour cannot be used as a predictive marker for chemotherapy response in advanced breast cancer
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