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Active Sensorimotor Augmentation in Robotics-Assisted Surgical Systems
Published in Terry M. Peters, Cristian A. Linte, Ziv Yaniv, Jacqueline Williams, Mixed and Augmented Reality in Medicine, 2018
Seyed Farokh Atashzar, Michael Naish, Rajni V. Patel
Using computerized, robotics-assisted surgical systems, it is now possible to augment the sensory and motor skills of surgeons during various surgical tasks, from macro to micro scales. Robots have made it possible for surgeons to conduct surgeries with an enhanced and augmented level of sensory awareness, despite the physical limitations that are clinically imposed to minimize surgical trauma. Robots have also enabled surgeons to conduct tasks with accuracies beyond the natural competence of humans. As a result, robots are able to provide new opportunities to relax several sensorimotor issues and restrictions, such as: visuomotor misalignment and poor ergonomics in MIS, natural hand tremors of surgeons, imprecise micro-manipulation, lack of depth perception in MIS, lack of haptic guidance, inability to perceive micro-forces, and the lack of articulated actuation in MIS. The ultimate goal of this technology has been to enhance the quality of surgery and the predictability of the outcomes. During the last two decades, performance, benefits, and efficacy of commercialized surgical robotic systems and several research platforms have been studied and validated in extensive clinical studies. In this chapter, we introduced sensorimotor augmentation techniques achieved using computerized, robotics-assisted surgical systems. Different categories, technologies, and techniques, together with the relevant literature, were examined, and potential challenges and unresolved research problems were discussed.
Methods in Molecular Biology
Published in Martin G. Pomper, Juri G. Gelovani, Benjamin Tsui, Kathleen Gabrielson, Richard Wahl, S. Sam Gambhir, Jeff Bulte, Raymond Gibson, William C. Eckelman, Molecular Imaging in Oncology, 2008
In nature, transformation does not occur in every species of bacteria. Instead, it takes place only in the species possessing proteins and enzymatic machinery necessary to bind free DNA molecules and transport them into the cytoplasm. Only cells that secrete a competence factor, competent cells, are considered able to serve as recipient cells in transformation. This natural capability of taking up DNA is called natural competence. However, there are mechanisms that can force passive incorporation of a plasmid into an artificially permeabilized cell; this is called artificial competence. For example, cell wall permeability to DNA can be induced by chilling cells in the presence of divalent cations such as Ca2+ or heating them. Electroporation is another way to make holes in bacterial (and other) cells, by briefly shocking them with an electric field of 10 to 20 kV/cm. If the plasmid is present when the shock is applied, it can enter the cell through these holes and natural membrane repair mechanisms will then close these holes.
Two decades of IVF: A critical appraisal
Published in Elisabeth Hildt, Dietmar Mieth, In Vitro Fertilisation in the 1990s, 2018
It is not difficult to understand the reason why IVF treatment could not remain in the hands of medical doctors for ever. The general interest in increasing patient and user autonomy in the health services has clashed with the more authoritarian and paternalistic practices of the medical profession, also in the area of reproductive services. It is harder to grasp why these technologies were not directly subjected to parliamentary control rather than to the assessment of ethical committees with only advisory powers. Of course it has to do with the way reproductive and genetic issues have been constructed as ethical issues rather than as social issues – which might have been just as appropriate. By institutionalising the reflection on genetic and reproductive technology in ethics committees, these issues have, at least to some extent, been placed outside the realm of those with an obvious vested interest – the medical profession – but also outside the established political forum – probably because the issues are felt to be of a different nature than those which political parties are organised to deal with. Thus the debate about these issues is opened up to include a broader group of participants, and we are now witnessing a broader and more democratic debate where all have a natural competence as human beings. In this way ethics committees helped the process of dissolving the monopoly of medical professionals on these issues and prepared the field for a later political take-over. Ethics and ethical committees have become a form of regulation – at least they have been for a while. Whether we are approaching a period where the elected politicians will take more direct responsibility for the new technology and its social impact remains to be seen.
Tracing the origins of extracellular DNA in bacterial biofilms: story of death and predation to community benefit
Published in Biofouling, 2021
Davide Campoccia, Lucio Montanaro, Carla Renata Arciola
A more complete frame for the interpretation of the origin of DNA present in the extracellular space of biofilms of human pathogens has emerged only in recent years. In an early phase, eDNA was thought not to be actively released by bacteria, but rather to derive from bacterial cells facing a process of natural death. With time it became more evident though that, at least in species such as Streptococcus pneumoniae, induction of natural competence could actively trigger cell lysis and DNA release from a subfraction of the cell population (Steinmoen et al. 2002). Over the last two decades, the extensive research work conducted on many bacterial species has started to shed more light on the processes leading to the presence of eDNA in the intercellular space, revealing a multitude of alternative and often redundant mechanisms that vary with the pathogenic species. The scheme in Figure 1 summarizes some of the main mechanisms implicated in eDNA production, which will be discussed in detail in the following sections.
Genetic exchange and reassignment in Porphyromonas gingivalis
Published in Journal of Oral Microbiology, 2018
Ingar Olsen, Tsute Chen, Gena D Tribble
It is well known that prokaryotes can respond dynamically to changing environments by genetic exchange [5]. P. gingivalis exchanges chromosomal DNA between strains by natural competence and conjugation [6–8]. By using antibiotic resistance markers, it was demonstrated that the strains ATCC 33277T and W83 of P. gingivalis were able to exchange chromosomal DNA resulting in offspring, which carried DNA from both donor and recipient [6]. The chimeras thereby created had altered phenotypic features as demonstrated through biofilm formation [9]. Natural competence affected by the competence protein ComF was found to be the predominant form of DNA transfer in P. gingivalis while transfer by a conjugation-like approach occurred at a lower frequency [6]. Subsequently, natural competence mechanisms have been detected in multiple P. gingivalis strains and the DNA uptake is not sensitive to the DNA source or modification status [6]. The major source for horizontal DNA transfer and allelic exchange between strains was found to be extracellular DNA present in P. gingivalis biofilms. Moreover, P. gingivalis may even scavenge DNA from other species as a nutritional source [6].
Phylogenetic diversity in fim and mfa gene clusters between Porphyromonas gingivalis and Porphyromonas gulae, as a potential cause of host specificity
Published in Journal of Oral Microbiology, 2020
Kaori Fujiwara-Takahashi, Takayasu Watanabe, Masahiro Shimogishi, Masaki Shibasaki, Makoto Umeda, Yuichi Izumi, Ichiro Nakagawa
However, fimA and fimCDE in P. gulae did not show a clear relationship with each other with respect to their distances from ATCC 33277 (Figure 4), despite that mfa1 and mfa345 showed a similar relationship to P. gingivalis. The distances, based on fimCDE and fimSR, seemed to reflect the phylogenetic distance from P. gingivalis, whereas the distances based on fimA were irrelevant to the phylogeny between P. gulae and P. gingivalis. The combination of fimA distant from P. gingivalis and fimA-related CDSs close to P. gingivalis, and vice versa, may characterize P. gulae as a species independent from P. gingivalis and lead to its unique habitats segregated from P. gingivalis. In P. gingivalis, homologous recombination was suggested to shape the genetic diversity among the strains [46–48]. Chromosomes in other P. gingivalis cells are potential sources of the recombination partner, transferred by conjugation [49,50]. Natural competence is also important for recombination by introducing extracellular DNA, which is released from P. gingivalis cells [47,51]. Although it has been still unknown whether these mechanisms are also valid in P. gulae, homologous recombination that would occur within P. gingivalis or P. gulae and would occur between P. gingivalis and P. gulae across the hosts, may be a possible reason for the phylogenetic differentiation of fimbrial genes between P. gingivalis and P. gulae, thereby resulting in the difference in host specificity.