Impact of COVID-19 on maxillofacial surgery practice: a worldwide survey

The outbreak of coronavirus disease 2019 (COVID-19) is rapidly changing our habits. To date, April 12, 2020, the virus has reached 209 nations, affecting 1.8 million people and causing more than 110,000 deaths. Maxillofacial surgery represents an example of a specialty that has had to adapt to this outbreak, because of the subspecialties of oncology and traumatology. The aim of this study was to examine the effect of this outbreak on the specialty of maxillofacial surgery and how the current situation is being managed on a worldwide scale. To achieve this goal, the authors developed an anonymous questionnaire which was posted on the internet and also sent to maxillofacial surgeons around the globe using membership lists from various subspecialty associations. The questionnaire asked for information about the COVID-19 situation in the respondent's country and in their workplace, and what changes they were facing in their practices in light of the outbreak. The objective was not only to collect and analyse data, but also to highlight what the specialty is facing and how it is handling the situation, in the hope that this information will be useful as a reference in the future, not only for this specialty, but also for others, should COVID-19 or a similar global threat arise again

Comparison between Eight-Axis Articulated Robot and Five-Axis CNC Gantry Laser Metal Deposition Machines for Fabricating Large Components

Featured Application: Laser metal deposition of large axisymmetric components. Laser metal deposition (LMD) is an additive manufacturing (AM) process capable of producing large components for the aerospace and oil and gas industries. This is achieved by mounting the deposition head on a motion system, such as an articulated robot or a gantry computer numerical control (CNC) machine, which can scan large volumes. Articulated robots are more flexible and less expensive than CNC machines, which on the other hand, are more accurate. This study compares two LMD systems with different motion architectures (i.e., an eight-axis articulated robot and a five-axis CNC gantry machine) in producing a large gas turbine axisymmetric component. The same process parameters were applied to both machines. The deposited components show no significant differences in geometry, indicating that the different performances in terms of accuracy of the two machines do not influence the outcome. The findings indicate that LMD can consistently produce large-scale axisymmetric metal components with both types of equipment. For such an application, the user has the option of using an articulated robot when flexibility and cost are essential, such as in a research context, or a CNC machine where ease of programming and process standardization are important elements, such as in an industrial environment

Enhancing productivity and efficiency in conventional laser metal deposition process for Inconel 718 – Part II: advancing the process performance

This paper is the second part of a work focused on optimizing the performance of conventional Laser Metal Deposition (C-LMD) process for Inconel 718 (IN718). In Part I, through an extensive experimental campaign on single tracks, the interplay between process parameters and their impact on the deposition rate, powder catchment efficiency, and clad geometry is examined. The parameters investigated include laser power, scan speed, powder feed rate, and standoff distance. By systematically adjusting these parameters, the aim is to identify optimal conditions that maximize productivity while maintaining a favorable clad shape for multi-pass multi-layer depositions. Part II starts from the findings and results of Part I by continuing the optimization on thick wall structures. These are utilized to assess the effect of 3D geometrical process parameters, specifically hatch spacing and Z-step, on process performance and stability. Based on the findings, further optimization procedure is presented, pushing the boundaries of the C-LMD process for IN718. By fine-tuning the process parameters, the capability of the C-LMD process to deposit fully dense IN718 with a productivity of 1500 g/h and a powder catchment efficiency of 70% is demonstrated. These results highlight the potential of C-LMD as a viable manufacturing technique for efficiently fabricating large components. Overall, this study contributes to a deeper understanding of the relationship between process parameters and performance in C-LMD for IN718. The insights gained from this research can guide the development of efficient and cost-effective LMD strategies, facilitating the practical implementation of this process in various industries

Enhancing productivity and efficiency in conventional laser metal deposition process for Inconel 718 - part I: the effects of the process parameters

The sustainable energy transition has spurred the development of technologies that minimize material and energy waste, such as additive manufacturing (AM). Laser metal deposition (LMD) is a promising AM technique, but its complexity and limited automation hinder its implementation in production chains. To enhance productivity, the high deposition rate LMD (HDR-LMD) technology has been developed, requiring advanced equipment and powerful laser sources. In contrast, the conventional LMD (C-LMD) process is simpler and less expensive to implement. This study aims to optimize the productivity and efficiency of C-LMD by adjusting laser power, scan speed, powder feed rate, and standoff distance on Inconel 718 single tracks. An innovative approach eliminates the need for cutting specimens to evaluate single tracks, allowing comprehensive geometric and performance characterization with limited operator involvement, making the analysis quicker and more robust. An extensive experimental campaign was conducted to examine the influence of process parameters on track geometry, productivity, and efficiency. A multi-objective optimization procedure identified parameter combinations maximizing productivity while maintaining high efficiency and desirable clad shape. The study attained deposition rates ranging from 700 to 800 g/h, with powder catchment efficiency ranging between 75 and 90%. These results were achieved using parameters including 1775 W of laser power, scan speeds ranging from 960 to 1140 mm/min, powder feed rates between 810 and 1080 g/h, and standoff distance of 9 mm. The study also clearly indicated that further potential for improving C-LMD process performance may be possible. The findings gathered in this paper are the base for the further optimization presented in the second part of the work, which is focused on multi-pass multi-layer and reaches deposition rates of 1500 g/h, promoting the implementation of C-LMD process at industrial level

Sobrevivência de Bacillus thurigiensis, antagonista a Hemileia vastatrix, no filoplano de cafeeiros.

O isolado B157 de Bacillus thurigiensis foi eficiente no biocontrole da ferrugem do cafeeiro em casa-de-vegetação e em cultivos orgânicos no campo. Para definir estratégias de uso do biocontrole, estudaram-se a dinâmica de sobrevivência do isolado B157 no filoplano de cafeeiro e a influência de diferentes fungicidas a base de cobre na sobrevivência do isolado, em casa-de-vegetação e campo. Para verificar o efeito de fungicidas cúpricos na sobrevivência de B157, pulverizou-se hidróxido de cobre em mudas ou sulfato de cobre em cafeeiros, em casa de vegetação e campo. Após a avaliação da densidade populacional de B157, verificou-se que em ambas as condições experimentais, a aplicação de fungicida, independente da fonte de cobre utilizada, reduziu a população da bactéria ao longo do tempo e o período de sobrevivência de B157. Em casa de vegetação, na primeira semana, a população de B157 reduziu-se, em média, 10 e 52% nas parcelas sem e com fungicida, respectivamente. A pulverização dos fungicidas reduziu o tempo de sobrevivência da bactéria, em casa de vegetação e no campo. Para controle da ferrugem no campo, poder-se-iam adotar duas estratégias: (i) pulverizar apenas o isolado B157 ou (ii) aplicar o isolado nas primeiras pulverizações e fungicidas cúpricos, posteriormente

Efeito do silício em alguns componentes de resistência a antracnose em linhagens de sorgo.

xEdição dos Resumos do XL Congresso Brasileiro de Fitopatologia, Maringá, PR, ago. 2007

Chemical control of guava rust (Puccinia psidii) in the Northern Region of Rio de Janeiro State, Brazil.

Fungicides were evaluated under field conditions for their efficacy in the control of guava rust (Puccinia psidii); five systemic fungicides (azoxystrobin, pyraclostrobin, cyproconazole, tebuconazole, triadimenol) and the protectant mancozeb. In a first trial, the fungicides were applied at two-week intervals intercalated with bi-weekly sprays of copper oxychloride. The initial incidence of rust on flower buds before treatment was 47%. Triadimenol and azoxystrobin were most effective in reducing the incidence of rust on fruit. The minimum rust incidence achieved with triadimenol was 12% compared to 84% in the control treatment (water). The initial level of rust on flower buds was particularly high for the tebuconazole treatment, which may have contributed to the ineffective control by this fungicide in the first trial. In the second trial, copper oxychloride sprays were applied when disease incidence on flower buds was low (7%). Azoxystrobin, tebuconazole, triadimenol and mancozeb treatments were started nine days after a second application of copper oxychloride. The fungicides were then applied at bi-weekly intervals and at the same concentrations as in the first trial. Triadimenol was again most effective in controlling rust, although its effect did not greatly differ from that of tebuconazole. The maximum disease incidence in all fungicide treatments was significantly lower than that observed in the control treatment

Novel bicistronic lentiviral vectors correct beta-Hexosaminidase deficiency in neural and hematopoietic stem cells and progeny: implications for in vivo and ex vivo gene therapy of GM2 gangliosidosis

The favorable outcome of in vivo and ex vivo gene therapy approaches in several Lysosomal Storage Diseases suggests that these treatment strategies might equally benefit GM2 gangliosidosis. Tay-Sachs and Sandhoff disease (the main forms of GM2 gangliosidosis) result from mutations in either the HEXA or HERB genes encoding, respectively, the alpha- or beta-subunits of the lysosomal beta-Hexosaminidase enzyme. In physiological conditions, alpha- and beta-subunits combine to generate beta-Hexosaminidase A (HexA, alpha beta) and beta-Hexosaminidase B (HexB, 1313). A major impairment to establishing in vivo or ex vivo gene therapy for GM2 gangliosidosis is the need to synthesize the alpha- and beta-subunits at high levels and with the correct stoichiometric ratio, and to safely deliver the therapeutic products to all affected tissues/organs. Here, we report the generation and in vitro validation of novel bicistronic lentiviral vectors (LVs) encoding for both the murine and human codon optimized Hexa and Hex!) genes. We show that these LVs drive the safe and coordinate expression of the alpha- and beta-subunits, leading to supranormal levels of beta-Hexosaminidase activity with prevalent formation of a functional HexA in SD murine neurons and glia, murine bone marrow-derived hematopoietic stem/progenitor cells (HSPCs), and human SD fibroblasts. The restoration/overexpression of beta-Hexosaminidase leads to the reduction of intracellular GM2 ganglioside storage in transduced and in cross-corrected SD murine neural progeny, indicating that the transgenic enzyme is secreted and functional. Importantly, bicistronic LVs safely and efficiently transduce human neurons/glia and CD34 + HSPCs, which are target and effector cells, respectively, in prospective in vivo and ex vivo GT approaches. We anticipate that these bicistronic LVs may overcome the current requirement of two vectors co-delivering the alpha- or beta-subunits genes. Careful assessment of the safety and therapeutic potential of these bicistronic LVs in the SD murine model will pave the way to the clinical development of LV-based gene therapy for GM2 gangliosidosis