Abelhas-sem-ferrão amazônicas defendem meliponários contra saques de outras abelhas

Entre as abelhas eussociais, dois gêneros apresentam estratégia de vida cleptobiótica, obtendo recursos alimentares de ninhos de outras abelhas ao invés de coletá-los em flores. Entre as espécies atacadas existe um gradiente de suscetibilidade ao roubo variando desde espécies vulneráveis até altamente resistentes. Neste trabalho nós descrevemos um ataque de Lestrimelitta rufipes a um ninho de Scaptotrigona sp. em um meliponário na Amazônia central (Amazonas, Brazil). O ninho atacado foi transferido para um meliponário com espécies resistentes (Duckeola ghilianii e Melipona fulva) e as interações foram descritas. As abelhas resistentes contra-atacaram e afugentaram as ladras protegendo o ninho de Scaptotrigona sp.. A presença de comportamento defensivo em gêneros não proximamente relacionados sugere que ele tenha evoluído mais de uma vez entre os Meliponini. Considerando o comportamento descrito, sugerimos a criação de espécies nativas resistentes em meliponários de regiões onde elas forem nativas, devido ao potencial que elas tem na proteção

Analysis of material removal rate and electrode wear in sinking EDM roughing strategies using different graphite grades

AbstractFor industrial applications graphite is becoming more and more the electrode material of choice for sinking EDM. Especially f or roughing graphite offers great advantages compared to copper electrodes. Optimized parameters lead to a very low tool wear rate combined with a high material removal rate. As a result the number of tool electrodes for a certain EDM task can be reduced significantly leadin g to very short machining time. A satisfactory explanation for these benefits could not be found until now. Therefore the specific wear behavior and material removal rate is investigated in detail in this paper and linked to the physical characteristics of the graphite material. In total 5 different kinds of graphite were chosen with significantly different physical characteristics concerning their specific electric resistance, thermal conductivity and grain size. The performance of each grade was evaluated in terms of material removal rate and tool wear for roughing

The First CIRP Conference on Biomanufacturing Influence of Electro Discharge Machining of Biodegradable Magnesium on the Biocompatibility peer-review under responsibility of Professor Mamoru Mitsuishi and Professor Paulo Bartolo

Abstract Biodegradable implants are in the focus of recent research approaches in the medical engineering sector for the treatment of many different defects. In comparison to permanent implants the risk of inflammatory reactions is significantly reduced and no foreign material is left in the body using degradable materials. Due to the extraordinary biocompatibility and initial structural stability, similar to the human bone, magnesium alloys are best suited for degradable orthopedic implants. But up until now the degradation of magnesium inside the human body is too fast and therefore the structural stability is lost too early. Newest research suggests that the degradation kinematic as well as the cell response of the implant can be improved by adjusting certain surface properties, e.g. complex micro-and macrostructures. Since these structures are very difficult to be machined with conventional processes, especially for complex and filigree 3D-structures, alternative manufacturing processes need to be developed. Electro Discharge Machining in combination with a Plasma Electrolytic Conversion of the surface is very well suited for the creation of geometries with high aspect ratios and microstructures. The focus of this paper lies on the investigation of the influence of the production processes on the biocompatibility of the machined part. The process chain for such implants will therefore be analyzed in regard to macro and micro surface properties using SEM and EDX-analysis. These results are then compared to biocompatibility testing concerning cell viability and toxicity

Long-term follow-up of gliomas treated with fractionated stereotactic irradiation

Eighteen patients have been treated for gliomas with fractionated stereotactic linear accelerator (LINAC) irradiation. A plastic halo ring secured with skull pins allows daily attachment of the patient to the stereotactic frame mounted on the linear accelerator. The patients received 9-31 fractions of 1.8-3 Gy/fraction over periods of 20-49 days. Total doses delivered stereotactically where 16-60 Gy (90% isodose) delivered to 3-7 cm diameter tumors. The six patients with glioblastoma had a median survival of 16 months (range 7-60 months). The two patients with anaplastic astrocytoma survived 7 and 78 months. Most of the patients with high grade tumors also received other adjuant treatments. Of the ten patients with low grade gliomas, one expired 66 months after treatment, and the remainder are alive 22-82 months after treatment. One pediatric patient displayed evidence of focal radiation injury with visual loss. No patient developed initial recurrence of tumor outside the focally irradiated field. Stereotactic localization of irradiation protects surrounding brain tissue; fractionation improves the therapeutic ratio. These extended follow-up data indicate that stereotactic restriction of radiation fields in treatment of gliomas does not result in deterioration of survival results. Further investigation is warranted into the use of higher focal fractionated radiation doses to attempt to improve local control and survival

General cognitive principles for learning structure in time and space

How are hierarchically structured sequences of objects, events or actions learned from experience and represented in the brain? When several streams of regularities present themselves, which will be learned and which ignored? Can statistical regularities take effect on their own, or are additional factors such as behavioral outcomes expected to influence statistical learning? Answers to these questions are starting to emerge through a convergence of findings from naturalistic observations, behavioral experiments, neurobiological studies, and computational analyses and simulations. We propose that a small set of principles are at work in every situation that involves learning of structure from patterns of experience and outline a general framework that accounts for such learning

Complexes with Furyl-Substituted 3-Hydroxychromone: Synthesis, Characterization and Fluorescence Studies

2-(2-Furyl)-3-hydroxychromone (HL) reacts with MII ions in the formation of quadratic [Cu(L)2] (3), octahedral [M(L)2(OH2)2] (M = Co (1), Ni (2), Zn (4), Mn (5)) and seesaw [M(L)2] (M = Sn (6), Pb (7)) complexes. Recrystallization of complexes 1-3 in presence of pyridine lead to [M(L)2(py)2] (1a-3a) adducts. All compounds were characterized by Fourier transform infrared spectroscopy (FTIR). Complexes 1-7 were analyzed by UV-Vis and diffuse reflectance spectroscopies. The estimated band gap energies range from 2.90-3.15 eV. The crystal structure of complexes 6 and 7 revealed the influence of the stereochemically active lone pair due to their electronic configuration ns2. An intense fluorescence emission band centered at approximately 600 nm (λexc centered at 340 nm) has been observed for complex 6 in the solid state. In N,N‑dimethylformamide (DMF) solution, complex 6 showed two emission bands (468 and 538 nm) when excited from 300 to 380 nm, and only one emission band (468 nm) when excited from 385 to 420 nm

Dose Rate Effect of 125I Irradiation on Normal Rabbit Eyes and Experimental Choroidal Melanoma

The dose rate effect of radiation by 125I plaque on choroidal melanoma and normal intraocular tissue was studied. In the first part of the experiment, high activity plaques (HAP) and low activity plaques (LAP) were implanted on rabbit eyes with experimental Greene choroidal melanoma to deliver a total dose of 10000 cGy to the tumor apex. The mean dose rate calculated at 0·5 mm from the inner sclera in eight eyes with high activity plaques was 3341·5 cGy hr -1 (1 cGy = 1 rad) while that in ten eyes with low activity plaques was 239·9 cGy hr -1. For tumors less than 1·0 mm in height, both groups showed complete tumor regression at the tumor implantation site after plaque treatment. For tumors more than 1·0 mm in height, two out of two eyes in the low activity plaque group and one of four eyes in the high activity plaque group failed to show complete tumor regression. Both LAP and HAP were effective in eradicating tumors, but logistic regression analysis demonstrates that HAP was more effective than LAP when adjustment was made for initial tumor height ( P = 0·032). Nine tumor control eyes without 125I plaque implantation demonstrated marked tumor growth within 3 weeks. In the second part of the experiment, 125I plaques were implanted on the sclera of 12 normal rabbits' eyes. Six received high dose rate plaque treatment, while the other six received low dose rate plaque treatment. Clinical and histologic examinations demonstrated more damaging effects to the normal chorioretinal tissues at the plaque implantation site in the high dose rate plaque group at 24 weeks of follow-up. These results suggest that high dose rate plaques are more effective than low dose rate plaques when tumor height is statistically controlled. However, high dose rate delivery increases the damaging effects on normal intraocular tissue