Angle Control of a Pneumatically Driven Musculoskeletal Model Based on Coordination of Agonist-Antagonist Muscle

In recent years, researchers have been actively pursuing research into developing robots that can be useful in many fields of industry (e.g., service, medical, and aging care). Such robots must be safe and flexible so that they can coexist with people. Pneumatic actuators are useful for achieving this goal because they are lightweight units with natural compliance. Our research focuses on joint angle control for a pneumatically driven musculoskeletal model. In such a model, we use a one-degree-of-freedom joint model and a five-fingered robot hand as test beds. These models are driven by low pressure-driven pneumatic actuators, and mimic the mechanism of the human hand and musculoskeletal structure, which has an antagonistic muscle pair for each joint. We demonstrated a biologically inspired control method using the parameters antagonistic muscle ratio and antagonistic muscle activity. The concept of the method is based on coordination of an antagonistic muscle pair using these parameters. We have investigated the validity of the proposed method both theoretically and experimentally, developed a feedback control system, and conducted joint angle control by implementing the test beds.ArticleJournal of Mechanics Engineering and Automation. 2(12):709-719 (2012)journal articl

Expressão e caracterização de uma forma N-Truncada da proteína Nifa de Azospirillum Brasilense

Resumo: Azospirillum brasilense é uma bactéria fixadora de nitrogênio que se associa com diversas plantas agrícolas de interesse comercial como o arroz, o milho e o trigo. É muito estudado por seu potencial como biofertilizante, podendo reduzir a utilização de fertilizantes químicos nitrogenados e consequentemente os danos ao meio ambiente, como a eutrofização de rios e a acidificação do solo. Neste microrganismo os genes responsáveis pela fixação de nitrogênio (genes nif) necessitam de uma proteína ativadora transcricional, a NifA. A proteína NifA tem sua atividade regulada pelos níveis de oxigênio e de íons NH4+ e possui três domínios funcionais. O domínio N-terminal é responsável pelo controle negativo dos níveis intracelulares de nitrogênio; o domínio central interage com o fator sigma-54 da RNA polimerase e possui um motivo de hidrólise de ATP e o domínio C-terminal possui um motivo hélice-volta-hélice responsável pela ligação da proteína ao DNA. Esses domínios são interligados por regiões interdomínio QL (N-terminal e Central) e IDL (Central e C-terminal). Na extremidade final do domínio central e início do interdomínio IDL há um motivo conservado de resíduos de cisteínas provavelmente envolvidos na sensibilidade da proteína ao oxigênio. Neste trabalho a proteína NifA de A. brasilense foi expressa e purificada em uma forma N-truncada fusionada a uma cauda contendo resíduos de histidina e caracterizada em ensaios de ligação ao DNA in vitro e de ativação transcricional in vivo. A proteína recombinante His-NifA N-truncada purificada atingiu 80% de pureza com rendimento de 0,43mg de proteína por litro de cultura. A proteína purificada foi capaz de se ligar à região promotora do gene nifB de Herbaspirillum seropedicae. Ensaios in vivo com a proteína NifA N-truncada contendo ou não cauda de histidina mostraram capacidade de ativar o promotor nifH de Klebsiella pneumoniae a partir de uma fusão nifH::lacZ na ausência de oxigênio. Nossos resultados também indicaram que a NifA N-truncada de A. brasilense parece ser menos sensível ao oxigênio que a NifA N-truncada de H. seropedicae

Controlling the kinetics of interferon transgene expression for improved gene therapy.

Interferon (IFN) gene based therapy has been studied for the treatment of many diseases such as viral infections, cancer and allergic diseases. Non-viral vectors, like plasmid DNA, are promising ways for delivering IFN genes, because of their low immunogenicity and toxicity compared with viral vectors. Potent therapeutic effects of IFN gene transfer will depend on the level and duration of transgene expression after in vivo administration. Therefore, controlling the kinetics of transgene expression of IFNs is a rational approach for improved gene therapy. The design and optimization of plasmid vectors, as well as their route/method of administration, is the key to obtaining high and persistent transgene expression. In this review, we aim to present experimental evidence about the relationships among the properties of plasmid vectors expressing IFNs, the kinetics of transgene expression, and therapeutic effects as well as safety issues

HnRNPA1 interacts with G-quadruplex in the TRA2B promoter and stimulates its transcription in human colon cancer cells

The human TRA2B gene consists of 10 exons and 9 introns and produces 5 splice isoforms (TRA2β1 to TRA2β5). TRA2B exon 2 encodes multiple premature termination codons. TRA2β1 lacks exon 2 and is translated into a functional transformer 2β (Tra2β) protein, whereas TRA2β4 contains 10 exons and works as a functional RNA. Overexpressed Tra2β and ectopic expression of TRA2β4 may be oncogenic. We found that heterogeneous nuclear ribonucleoprotein (hnRNP)A1 and hnRNPU interacted with TRA2β4 exon 2. Minigene assays revealed that hnRNPA1 facilitated inclusion of exon 2, whereas hnRNPU promoted its skipping. However, knockdown of hnRNPA1 or hnRNPU reduced both TRA2β1 and TRA2β4 levels, and overexpression of these hnRNPs increased levels of both isoforms, suggesting that hnRNPA1 and hnRNPU mainly regulate the transcription of TRA2B. In fact, hnRNPA1 and hnRNPU positively regulated the promoter activity of TRA2B. Circular dichroism analyses, electrophoretic mobility shift assays and chromatin immunoprecipitation assays demonstrated the presence of G-quadruplex (G4) formation in the promoter of TRA2B. Formation of G4 suppressed TRA2B transcription, whereas hnRNPA1, but not hnRNPU, interacted with the G4 to facilitate transcription. Our results suggest that hnRNPA1 may modulate TRA2B transcription through its regulation of G4 formation in its promoter in colon cancer cells

Evaluation of ambipolar carrier mobility in alkyl-substituted phthalocyanine thin film

Yuki Nishikawa, Yuya Nakata, Shigehiro Ikehara, Akihiko Fujii, and Masanori Ozaki "Evaluation of ambipolar carrier mobility in alkyl-substituted phthalocyanine thin film," Journal of Photonics for Energy 8(3), 032214 (15 May 2018). DOI: https://doi.org/10.1117/1.JPE.8.03221

Concept of Virtual Incision for Minimally Invasive Surgery

Minimally invasive surgery has been introduced to various surgical fields for its benefits such as smaller scars and less pain as compared to open surgery. Highly skilled surgical techniques are required for surgeons to conduct minimally invasive surgery with fewer ports, whereas minimally invasive surgery has a number of advantages for patients. Single-incision laparoscopic surgery (SILS), in which surgical instruments and a laparoscope are inserted through a single port, has better cosmetic results than conventional multi-incision surgery; moreover, the scar is invisible when the port is opened in navel. However, instrument collisions and visual defects often occur due to the limited space of the single opening. We propose a new surgical approach entitled “virtual incision” that enables surgeons to increase the number of openings virtually. Using our approach, we have developed two types of master-slave surgical robot systems for SILS—remote-operated and local-operated systems—which have operability close to that of multiple-incision surgery. Through evaluation of these systems, we demonstrated that the visual field and operability during virtual incision surgery are similar to those of conventional multi-incision surgery. Our surgical approach can be applied to not only single-incision surgery but also multi-incision surgery, and is very likely to improve operability

siVirus: web-based antiviral siRNA design software for highly divergent viral sequences

siVirus () is a web-based online software system that provides efficient short interfering RNA (siRNA) design for antiviral RNA interference (RNAi). siVirus searches for functional, off-target minimized siRNAs targeting highly conserved regions of divergent viral sequences. These siRNAs are expected to resist viral mutational escape, since their highly conserved targets likely contain structurally/functionally constrained elements. siVirus will be a useful tool for designing optimal siRNAs targeting highly divergent pathogens, including human immunodeficiency virus (HIV), hepatitis C virus (HCV), influenza virus and SARS coronavirus, all of which pose enormous threats to global human health

Mobile locally operated detachable end-effector manipulator for endoscopic surgery

Purpose\n Local surgery is safer than remote surgery because emergencies can be more easily addressed. Although many locally operated surgical robots and devices have been developed, none can safely grasp organs and provide traction. A new manipulator with a detachable commercial forceps was developed that can act as a third arm for a surgeon situated in a sterile area near the patient. This mechanism can be disassembled into compact parts that enable mobile use.Methods\n A mobile locally operated detachable end-effector manipulator (LODEM) was developed and tested. This device uses crank-slider and cable-rod mechanisms to achieve 5 degrees of freedom and an acting force of more than 5 N. The total mass is less than 15 kg. The positional accuracy and speed of the prototype device were evaluated while performing simulated in vivo surgery.Results\n The accuracy of the mobile LODEM was 0.4 mm, sufficient for handling organs. The manipulator could be assembled and disassembled in 8 min, making it highly mobile. The manipulator could successfully handle the target organs with the required level of dexterity during an in vivo laparoscopic surgical procedure.Conclusions\n A mobile LODEM was designed that allows minimally invasive robotically assisted endoscopic surgery by a surgeon working near the patient. This device is highly promising for robotic surgery applications.ArticleINTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY. 10(2):161-169 (2015)journal articl

DNA density-dependent uptake of DNA origami-based two-or three-dimensional nanostructures by immune cells

DNA nanostructures are expected to be applied for targeted drug delivery to immune cells. However, the structural properties of DNA nanostructures required for the delivery have not fully been elucidated. In this study, we focused on the DNA density that can be important for the their recognition and uptake by immune cells. To examine this, DNA nanostructures with almost identical molecular weights and structural flexibility, but with different shapes and DNA densities, were designed using DNA origami technology. We compared the following five types of DNA nanostructures, all of which consisted of ten DNA helices using an identical circular, single-stranded scaffold and staples. Rec180 had a rectangular-shaped, almost flat structure. Rec90, Rec50 and Rec0 were bent forms of Rec180 at the center by 90, 50 or 0 degrees, respectively. Rec50/50 has two bends of 50 degrees each so that the both ends stick together to form a triangular prism shape. The fluctuation, or flexibility, of these DNA nanostructures under solution conditions was estimated using CanDo software. The DNA density estimated from the average distance between any two of the ten DNA helices in the DNA nanostructures was different among them; Rec50, Rec0 and Rec50/50 had a higher density than Rec180 and Rec90. Agarose gel electrophoresis and atomic force microscopy showed that all of the nanostructures were prepared with high yield. Flow cytometry analysis revealed that the uptake of DNA nanostructures by murine macrophage-like RAW264.7 cells was higher for those with higher DNA density than those with low density. There was a positive correlation between the density and cellular uptake. These results indicate that DNA nanostructures with high DNA density are suitable for delivery to immune cells

Development and evaluation of a master-slave robot system for single-incision laparoscopic surgery

Single-incision laparoscopic surgery (SILS) brings cosmetic benefits for patients, but this procedure is more difficult than laparoscopic surgery. In order to reduce surgeons' burden, we have developed a master-slave robot system which can provide robot-assisted SILS as if it were performing conventional laparoscopic surgery and confirmed the feasibility of our proposed system. The proposed system is composed of an input device (master side), a surgical robot system (slave side), and a control PC. To perform SILS in the same style as regular laparoscopic surgery, input instruments are inserted into multiple incisions, and the tip position and pose of the left-sided (right-sided) robotic instrument on the slave side follow those of the right-sided (left-sided) input instruments on the master side by means of a control command from the PC. To validate the proposed system, we defined four operating conditions and conducted simulation experiments and physical experiments with surgeons under these conditions, then compared the results. In the simulation experiments, we found learning effects between trials (P = 0.00013 0.1), and the task time of our system was significantly shorter than the simulated SILS (P = 0.011 < 0.05). In the physical experiments, our system performed SILS more easily, efficiently, and intuitively than the other operating conditions. Our proposed system enabled the surgeons to perform SILS as if they were operating conventionally with laparoscopic techniques.ArticleINTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY. 7(2):289-296 (2012)journal articl