Top-down and bottom-up neurodynamic evidence in patients with tinnitus

AbstractAlthough a peripheral auditory (bottom-up) deficit is an essential prerequisite for the generation of tinnitus, central cognitive (top-down) impairment has also been shown to be an inherent neuropathological mechanism. Using an auditory oddball paradigm (for top-down analyses) and a passive listening paradigm (for bottom-up analyses) while recording electroencephalograms (EEGs), we investigated whether top-down or bottom-up components were more critical in the neuropathology of tinnitus, independent of peripheral hearing loss. We observed significantly reduced P300 amplitudes (reflecting fundamental cognitive processes such as attention) and evoked theta power (reflecting top-down regulation in memory systems) for target stimuli at the tinnitus frequency of patients with tinnitus but without hearing loss. The contingent negative variation (reflecting top-down expectation of a subsequent event prior to stimulation) and N100 (reflecting auditory bottom-up selective attention) were different between the healthy and patient groups. Interestingly, when tinnitus patients were divided into two subgroups based on their P300 amplitudes, their P170 and N200 components, and annoyance and distress indices to their tinnitus sound were different. EEG theta-band power and its Granger causal neurodynamic results consistently support a double dissociation of these two groups in both top-down and bottom-up tasks. Directed cortical connectivity corroborates that the tinnitus network involves the anterior cingulate and the parahippocampal areas, where higher-order top-down control is generated. Together, our observations provide neurophysiological and neurodynamic evidence revealing a differential engagement of top-down impairment along with deficits in bottom-up processing in patients with tinnitus but without hearing loss

One-pot Enzymatic Synthesis of Deoxy-thymidine-diphosphate (TDP)-2-deoxy-∝-d-glucose Using Phosphomannomutase

Production of deoxy-thymidine-diphosphate (TDP)-sugars as substrates of glycosyltransferases, has been one of main hurdles for combinatorial antibiotic biosynthesis, which combines sugar moiety with aglycon of various antibiotics. Here, we report the one-pot enzymatic synthesis of TDP-2-deoxy-glucose employing high efficient TMP kinase (TMK; E.C. 2.7.2.12), acetate kinase (ACK; E.C. 2.7.1.21), and TDP-glucose synthase (TGS; E.C. 2.7.7.24) with phosphomannomutase (PMM; E.C. 5.4.2.8). In this study, replacing phosphoglucomutase (PGM; E.C. 5.4.2) by PMM from Escherichia coli gave four times higher specific activity on 2-deoxy-6-phosphate glucose, suggesting that the activity on 2-deoxy-glucose-6-phosphate was mainly affected by PMM activity, not PGM activity. Using an in vitro system starting from TMP and 2-deoxy-glucose-6-phosphate glucose, TDP-2-deoxy-glucose (63% yield) was successfully synthesized. Considering low productivity of NDP-sugars from cheap starting materials, this paper showed how production of NDP-sugars could be enhanced by controlling mutase activity

Development of software for computing forming information using a component based approach

ABSTRACTIn shipbuilding industry, the manufacturing technology has advanced at an unprecedented pace for the last decade. As a result, many automatic systems for cutting, welding, etc. have been developed and employed in the manufacturing process and accordingly the productivity has been increased drastically. Despite such improvement in the manufacturing technology, however, development of an automatic system for fabricating a curved hull plate remains at the beginning stage since hardware and software for the automation of the curved hull fabrication process should be developed differently depending on the dimensions of plates, forming methods and manufacturing processes of each shipyard. To deal with this problem, it is necessary to create a “plug-in” framework, which can adopt various kinds of hardware and software to construct a full automatic fabrication system. In this paper, a framework for automatic fabrication of curved hull plates is proposed, which consists of four components and related software. In particular the software module for computing fabrication information is developed by using the ooCBD development methodology, which can interface with other hardware and software with minimum effort. Examples of the proposed framework applied to medium and large shipyards are presented

GPR-Based Landmine Detection and Identification Using Multiple Features

This paper presents a method to identify landmines in various burial conditions. A ground penetration radar is used to generate data set, which is then processed to reduce the ground effect and noise to obtain landmine signals. Principal components and Fourier coefficients of the landmine signals are computed, which are used as features of each landmine for detection and identification. A database is constructed based on the features of various types of landmines and the ground conditions, including the different levels of moisture and types of ground and the burial depths of the landmines. Detection and identification is performed by searching for features in the database. For a robust decision, the counting method and the Mahalanobis distance-based likelihood ratio test method are employed. Four landmines, different in size and material, are considered as examples that demonstrate the efficiency of the proposed method for detecting and identifying landmines