Underwater Optical-Sonar Image Fusion Systems.

Unmanned underwater operations using remotely operated vehicles or unmanned surface vehicles are increasing in recent times, and this guarantees human safety and work efficiency. Optical cameras and multi-beam sonars are generally used as imaging sensors in underwater environments. However, the obtained underwater images are difficult to understand intuitively, owing to noise and distortion. In this study, we developed an optical and sonar image fusion system that integrates the color and distance information from two different images. The enhanced optical and sonar images were fused using calibrated transformation matrices, and the underwater image quality measure (UIQM) and underwater color image quality evaluation (UCIQE) were used as metrics to evaluate the performance of the proposed system. Compared with the original underwater image, image fusion increased the mean UIQM and UCIQE by 94% and 27%, respectively. The contrast-to-noise ratio was increased six times after applying the median filter and gamma correction. The fused image in sonar image coordinates showed qualitatively good spatial agreement and the average IoU was 75% between the optical and sonar pixels in the fused images. The optical-sonar fusion system will help to visualize and understand well underwater situations with color and distance information for unmanned works.

A Fully Implantable Miniaturized Liquid Crystal Polymer (LCP)-Based Spinal Cord Stimulator for Pain Control.

Spinal cord stimulation is a therapy to treat the severe neuropathic pain by suppressing the pain signal via electrical stimulation of the spinal cord. The conventional metal packaged and battery-operated implantable pulse generator (IPG) produces electrical pulses to stimulate the spinal cord. Despite its stable operation after implantation, the implantation site is limited due to its bulky size and heavy weight. Wireless communications including wireless power charging is also restricted, which is mainly attributed to the electromagnetic shielding of the metal package. To overcome these limitations, here, we developed a fully implantable miniaturized spinal cord stimulator based on a biocompatible liquid crystal polymer (LCP). The fabrication of electrode arrays in the LCP substrate and monolithically encapsulating the circuitries using LCP packaging reduces the weight (0.4 g) and the size (the width, length, and thickness are 25.3, 9.3, and 1.9 mm, respectively). An inductive link was utilized to wirelessly transfer the power and the data to implanted circuitries to generate the stimulus pulse. Prior to implantation of the device, operation of the pulse generator was evaluated, and characteristics of stimulation electrode such as an electrochemical impedance spectroscopy (EIS) were measured. The LCP-based spinal cord stimulator was implanted into the spared nerve injury rat model. The degree of pain suppression upon spinal cord stimulation was assessed via the Von Frey test where the mechanical stimulation threshold was evaluated by monitoring the paw withdrawal responses. With no spinal cord stimulation, the mechanical stimulation threshold was observed as 1.47 ± 0.623 g, whereas the stimulation threshold was increased to 12.7 ± 4.00 g after spinal cord stimulation, confirming the efficacy of pain suppression via electrical stimulation of the spinal cord. This LCP-based spinal cord stimulator opens new avenues for the development of a miniaturized but still effective spinal cord stimulator.

Genome-wide reorganization of histone H2AX toward particular fragile sites on cell activation.

γH2AX formation by phosphorylation of the histone variant H2AX is the key process in the repair of DNA lesions including those arising at fragile sites under replication stress. Here we demonstrate that H2AX is dynamically reorganized to preoccupy γH2AX hotspots on increased replication stress by activated cell proliferation and that H2AX is enriched in aphidicolin-induced replisome stalling sites in cycling cells. Interestingly, H2AX enrichment was particularly found in genomic regions that replicate in early S phase. High transcription activity, a hallmark of early replicating fragile sites, was a determinant of H2AX localization. Subtelomeric H2AX enrichment was also attributable to early replication and high gene density. In contrast, late replicating and infrequently transcribed regions, including common fragile sites and heterochromatin, lacked H2AX enrichment. In particular, heterochromatin was inaccessible to H2AX incorporation, maybe partly explaining the cause of mutation accumulation in cancer heterochromatin. Meanwhile, H2AX in actively dividing cells was intimately colocalized with INO80. INO80 silencing reduced H2AX levels, particularly at the INO80-enriched sites. Our findings suggest that active DNA replication is accompanied with the specific localization of H2AX and INO80 for efficient damage repair or replication-fork stabilization in actively transcribed regions.

Genetic landscape of open chromatin in yeast.

Chromatin regulation underlies a variety of DNA metabolism processes, including transcription, recombination, repair, and replication. To perform a quantitative genetic analysis of chromatin accessibility, we obtained open chromatin profiles across 96 genetically different yeast strains by FAIRE (formaldehyde-assisted isolation of regulatory elements) assay followed by sequencing. While 5∼10% of open chromatin region (OCRs) were significantly affected by variations in their underlying DNA sequences, subtelomeric areas as well as gene-rich and gene-poor regions displayed high levels of sequence-independent variation. We performed quantitative trait loci (QTL) mapping using the FAIRE signal for each OCR as a quantitative trait. While individual OCRs were associated with a handful of specific genetic markers, gene expression levels were associated with many regulatory loci. We found multi-target trans-loci responsible for a very large number of OCRs, which seemed to reflect the widespread influence of certain chromatin regulators. Such regulatory hotspots were enriched for known regulatory functions, such as recombinational DNA repair, telomere replication, and general transcription control. The OCRs associated with these multi-target trans-loci coincided with recombination hotspots, telomeres, and gene-rich regions according to the function of the associated regulators. Our findings provide a global quantitative picture of the genetic architecture of chromatin regulation.

Genome-wide profiles of H2AX and γ-H2AX differentiate endogenous and exogenous DNA damage hotspots in human cells.

Phosphorylation of the histone variant H2AX forms γ-H2AX that marks DNA double-strand break (DSB). Here, we generated the sequencing-based maps of H2AX and γ-H2AX positioning in resting and proliferating cells before and after ionizing irradiation. Genome-wide locations of possible endogenous and exogenous DSBs were identified based on γ-H2AX distribution in dividing cancer cells without irradiation and that in resting cells upon irradiation, respectively. γ-H2AX-enriched regions of endogenous origin in replicating cells included sub-telomeres and active transcription start sites, apparently reflecting replication- and transcription-mediated stress during rapid cell division. Surprisingly, H2AX itself, prior to phosphorylation, was specifically located at these endogenous hotspots. This phenomenon was only observed in dividing cancer cells but not in resting cells. Endogenous H2AX was concentrated on the transcription start site of actively transcribed genes but was irrelevant to pausing of RNA polymerase II (pol II), which precisely coincided with γ-H2AX of endogenous origin. γ-H2AX enrichment upon irradiation also coincided with actively transcribed regions, but unlike endogenous γ-H2AX, it extended into the gene body and was not specifically concentrated on the pausing site of pol II. Sub-telomeres were less responsive to external DNA damage than to endogenous stress. Our findings provide insight into DNA repair programs of cancer and may have implications for cancer therapy.

Rhodium-catalyzed oxidative C-H activation/cyclization for the synthesis of phosphaisocoumarins and phosphorous 2-pyrones.

Rhodium-catalyzed cyclization of phosphinic acids and phosphonic monoesters with alkynes has been developed. The oxidative annulation proceeds with complete conversion of phosphinic acid derivatives and allowed the atom-economic preparation of useful phosphaisocoumarins with high yield and selectivity. The reaction is tolerant of extensive substitution on the phosphinic acid, phosphonic monoester and alkyne, including halides, ketone, and hydroxyl groups as substituents. Furthermore, we found that alkenylphosphonic monoesters proceed to give a wide range of phosphorus 2-pyrones through oxidative annulation with alkynes. Mechanistic studies revealed that C-H bond metalation was the rate-limiting step.

Cervicofacial tissue infarction in patients with acute invasive fungal sinusitis: prevalence and characteristic MR imaging findings.

INTRODUCTION: Tissue infarction is known as one of the characteristic features of invasive fungal sinusitis (IFS). The purpose of this study was to investigate the prevalence and characteristic MR imaging findings of cervicofacial tissue infarction (CFTI) associated with acute IFS. METHODS: We retrospectively reviewed MR images in 23 patients with histologically or microbiologically proven acute IFS. CFTI was defined as an area of lack of enhancement in and around the sinonasal tract on contrast-enhanced T1-weighted images. We divided CFTI into two groups, i.e., intrasinonasal and extrasinonasal. Particular attention was paid to the location of extrasinonasal CFTI and the signal intensity of CFTI on T1- and T2-weighted images. The presence of bone destruction on CT scans was also recorded. RESULTS: CFTI was found in 17 (74%) of 23 patients. All of these 17 patients had intrasinonasal CFTI, and 13 patients also had extrasinonasal CFTI. All 13 patients with extrasinonasal CFTI died of disease directly related to IFS. Various locations were involved in the 13 patients with extrasinonasal CFTI, including the orbit (n = 8), infratemporal fossa (n = 7), intracranial cavity (n = 3), and oral cavity and/or facial soft tissue (n = 4). Various signal intensities were noted at the area of CFTI on T1- and T2-weighted images. Bone destruction was found on CT scans in only 3 of 17 patients with CFTI. CONCLUSION: CFTI with preservation of the bony wall of the involved sinonasal tract may be a characteristic MR imaging finding of acute IFS. The mortality is very high once the lesion extends beyond the sinonasal tract.

Why Does the Impact of Psychological Empowerment Increase Employees' Knowledge-Sharing Intention? A Moderated Mediation Model of Belonging and Perceived Organizational Support.

This study examines the role of a sense of belonging in the relationship between the impact of psychological empowerment (PE) and employees' knowledge-sharing intention (KSI). The research finding based on a survey sample of 422 full-time employees collected in South Korea reports that a sense of belonging is a key mediator that translates the effect of an employee's perceived impact on the work environment into their KSI. The moderated mediation model shows that the mediating effect of a sense of belonging is more significant when employees perceive that organizational support is high. This study advances the literature on employee motivation and knowledge sharing by offering insights into the role played by employees' sense of control and influence (i.e., impact) in developing social connections, which in turn influence their intention to share knowledge.

The ways to avoid abusive supervision: the moderating effects of the characteristics of supervisors and subordinates on abusive supervision.

Following the recent emphasis on supervisory interactions in abusive supervision, this study explains why and how supervisors' job insecurity and authoritarianism are related to abusive supervision and how subordinates' characteristics, agreeableness and negotiating resistance interact with the effects of supervisors' characteristics. We conducted a field study with 261 supervisor and subordinate dyads in South Korea, and the study findings confirmed that supervisors' authoritarianism is positively related to abusive supervision and that the effect is enhanced when subordinates are highly agreeable and display resistant behaviors. The study contributes to the leadership literature, particularly on abusive supervision and personality. Moreover, our findings have practical implications for employees to manage their work relationships with their supervisors or subordinates.

Comparative study on gamma-ray detectors for in-situ ocean radiation monitoring system.

Large-sized crystals and state-of-the-art photosensors are desirable to cope with low environmental radioactivity (e.g., 1-2 Bq∙m-3137Cs in surface seawater) for homeland security purposes. We compared the performances of two different gamma-ray detector assemblies, GAGG crystal + silicon photomultiplier (SiPM) and NaI(Tl) crystal + photomultiplier tube, for our mobile in-situ ocean radiation monitoring system. We performed energy calibration, followed by water tank experiments with varying the depth of a137Cs point source. Experimental energy spectra were compared with MCNP-simulated spectra with identical setup and the consistency was validated. We finally assessed the detection efficiency and minimum detectable activity (MDA) of the detectors. Both GAGG and NaI detectors exhibited favorable energy resolutions (7.98 ± 0.13% and 7.01 ± 0.58% at 662 keV, respectively) and MDAs (33.1 ± 0.0645 and 13.5 ± 0.0327 Bq∙m-3 for 24-h 137Cs measurement, respectively). Matching the geometry of the GAGG crystal with that of the NaI crystal, the GAGG detector outperformed the NaI detector. The results demonstrated that the GAGG detector is potentially advantageous over the NaI detector in detection efficiency and compactness.

Totally implantable enzymatic biofuel cell and brain stimulator operating in bird through wireless communication.

Animals digest food to fuel brain neurometabolism via cellular respiration. This study demonstrates the combination of a biofuel cell (BFC) and an animal brain stimulator (ABS) implanted in a pigeon. Glucose oxidation and oxygen reduction in an enzymatic BFC supplied electrical power to the ABS. Power from the BFC reached 0.12 mW in vitro and 0.08 mW in vivo using only the natural glucose and oxygen in the pigeon's body. A power management integrated circuit is used to harvest energy from the in vivo BFC at a rate of 28.4 mJ over 10 min, which is sufficient for intermittent neurostimulation.

Palatal implant system can provide effective treatment for obstructive sleep apnea by recovering retropalatal patency.

OBJECTIVE: Obstructive sleep apnea (OSA) is a disorder with a high prevalence rate that may induce serious complications. Recent progress in the area of hypoglossal nerve stimulation has played a role as an alternative to conventional therapies though, some patients having retropalatal collapse still have not benefitted. Therefore, here we propose a new type of upper-airway stimulation, referred to as the palatal implant system, which recovers the upper-airway patency by electrically stimulating the soft palate. APPROACH: The system consists of two major parts: an implant that stimulates the soft palate through electrodes and an intra-oral device that delivers power and data simultaneously to the implant via an inductive link. Evaluations of the system are conducted in bench-top, in vitro, and in vivo tests to evaluate its feasibility as an OSA treatment, and the potential development of the system is addressed in the discussion section. MAIN RESULTS: In the bench-top test, the power efficiency was 12.4% at d = 5 mm and the system could operate up to 8 mm distance in a bio-medium. Data transmission was also successful at distances ranging 2 to 8 mm within an error margin of 10%. The measured CSCc and the impedance magnitude of the electrode were 62.25 mC cm-2 and 390 Ω, respectively, proving a feasibility of the electrode as a stimluator interface. The system was applied to a rabbit and contraction of the soft palate muscle was recorded via a C-arm fluoroscopy. SIGNIFICANCE: As a proof of concept, we suggest and demonstrate the palatal implant system as a new therapy for those undergoing treatment for OSA.

Determination of glucose generation rate from various types of glycemic carbohydrates by mammalian glucosidases anchored in the small intestinal tissue.

The supernatant from rat intestinal acetone powder (RIAP) was used as a source of mammalian glucosidases to determine the digestion properties of glycemic-carbohydrates. We hypothesized that many glucosidases are still anchored to the precipitated-intestinal tissues with available enzymes, and developed a method using the RIAP suspension to optimize the in vitro carbohydrate digestion model. The glucose production from various types of glycemic ingredients by RIAP suspension showed that this carbohydrate-hydrolysis model using the entire spectrum of glucosidases can be applied in an in vitro assay to determine carbohydrate quality from glycemic food products at the mammalian level. This approach better mimics the mammalian situation compared to other assays to determine the glycemic-carbohydrate digestion properties that employ fungal/microbial glucosidases that have different hydrolytic activities compared to mammalian enzymes. The method can also be used to determine the inhibitory effects of α-glucosidase inhibitors to attenuate the post-prandial blood glucose level.

A Fully Implantable Wireless Stimulation System for Pigeon Navigation.

Navigation of freely moving animals has been studied for potential application to emergency situations and hazardous environments. A fully implantable stimulation system for remote animal navigation was proposed and applied to living pigeons. The animal navigation system, consisting of an external controller and a neural stimulator, was designed based on the anatomy of the pigeons. Depth electrodes were fabricated based on the anatomy of target pigeon brain regions. The fabricated neural stimulators received data wirelessly from the external controller and generated biphasic current pulses with preset parameters of amplitude, duration, and rate. The average impedance of the fabricated electrodes was 12.0∠-13.05° kΩ at 1 kHz. The neural stimulator was implanted on the dorsal side, and the depth electrodes were inserted into the formatio reticularis medialis mesencephali (FRM). When successive current pulses with an amplitude of 400 µA, a rate of 58 Hz, and a duration of 80 µs were applied to the target regions at 0.85 s intervals, turning/circling behaviors were induced for 6.2 s. The feasibility of the proposed wireless stimulation system was demonstrated in vivo.

Impact of transcriptional properties on essentiality and evolutionary rate.

We characterized general transcriptional activity and variability of eukaryotic genes from global expression profiles of human, mouse, rat, fly, plants, and yeast. The variability shows a higher degree of divergence between distant species, implying that it is more closely related to phenotypic evolution, than the activity. More specifically, we show that transcriptional variability should be a true indicator of evolutionary rate. If we rule out the effect of translational selection, which seems to operate only in yeast, the apparent slow evolution of highly expressed genes should be attributed to their low variability. Meanwhile, rapidly evolving genes may acquire a high level of transcriptional variability and contribute to phenotypic variations. Essentiality also seems to be correlated with the variability, not the activity. We show that indispensable or highly interactive proteins tend to be present in high abundance to maintain a low variability. Our results challenge the current theory that highly expressed genes are essential and evolve slowly. Transcriptional variability, rather than transcriptional activity, might be a common indicator of essentiality and evolutionary rate, contributing to the correlation between the two variables.

Not all differentiation is the same: Examining the moderating effects of leader-member exchange (LMX) configurations.

Leaders often influence whether an employee stays or quits and yet research in collective turnover, or turnover at the work-unit level, has neglected leadership as a key antecedent. In the current study we examine how the quality of leader-member relationships within a group (i.e., leader-member exchange, LMX) influences building a shared mindset of collective organizational commitment and ultimately influences collective turnover. We build on a key tenet of LMX theory that leaders form differentiated relationships with followers and propose that not all LMX differentiation is the same and therefore, researchers must take into account the configuration, or mix of high and low LMX relationships, within a group. We expect LMX configurations will moderate the influence of LMX differentiation on collective turnover through the mechanism of collective organizational commitment. We find 5 configurations of LMX relationships, including a bimodal, solo-status low LMX, solo-status high LMX, and 2 fragmented configurations. As hypothesized, LMX differentiation positively relates to collective organizational commitment and negatively relates to collective turnover in a solo-status low LMX configuration and a fragmented LMX configuration, and negatively relates to collective organizational commitment and positively relates to collective turnover in a bimodal configuration. Theoretical implications and future research directions are discussed. (PsycINFO Database Record

Preliminary Study of Palatal Implant for Sleep Apnea Control.

A fully-implantable device for treating obstructive sleep apnea (OSA) is conceptually suggested using soft palate stimulation. In this research, two in vivo studies were conducted to demonstrate electrical and physical feasibilities of the suggested device. First, electrical stimulation was delivered to the soft palate of a rabbit using a stimulator ASIC. The stimulation frequencies were swept from 20 Hz to 200 Hz to find out the appropriate parameter. Also, threshold level of the current pulse was evaluated to be 1.10 mA with an observance of a C-arm fluoroscopy. Second, a mock-up was fabricated with liquid crystal polymer (LCP), reflecting dimensions of the suggested device. The mock-up was inserted toward the soft palate of a rabbit by incising the hard palate in a lateral direction. After the mock-up was inserted, protrusion of the device was not detected and the subject stayed alive for at least a month at the time of this writing. Finally, several discussions on the palatal implant fabrication with LCP are presented.

Effects of raw potato starch on body weight with controlled glucose delivery.

Starch digestion in the gastrointestinal tract has different properties depending on its botanical source. In this study, corn, wheat, rice, and potato starches were used to test the digestion properties of mammalian mucosal α-glucosidase in an in vitro assay, and their physiological effects were investigated in male C57BL/6 mice. The results clearly demonstrated that potato starch caused the lowest rates of glucose generation, suggesting that it can attenuate the postprandial glucose spike. Interestingly, a potato starch-based diet caused significantly (P < 0.05) lower weight gain and fat accumulation compared to diets based on other starches, through increased insulin sensitivity. This result suggests that potato starch-based products can be used to regulate postprandial blood glucose levels, aiding in the control of metabolic diseases.

Nerve cuff electrode using embedded magnets and its application to hypoglossal nerve stimulation.

OBJECTIVE: A novel nerve cuff electrode with embedded magnets was fabricated and developed. In this study, a pair of magnets was fully embedded and encapsulated in a liquid crystal polymer (LCP) substrate to utilize magnetic force in order to replace the conventional installing techniques of cuff electrodes. In vitro and in vivo experiments were conducted to evaluate the feasibility of the magnet-embedded nerve cuff electrode (MENCE). Lastly, several issues pertaining to the MENCE such as the cuff-to-nerve diameter ratio, the force of the magnets, and possible concerns were discussed in the discussion section. APPROACH: Electrochemical impedance spectrum and cyclic voltammetry assessments were conducted to measure the impedance and charge storage capacity of the cathodal phase (CSCc). The MENCE was installed onto the hypoglossal nerve (HN) of a rabbit and the movement of the genioglossus was recorded through C-arm fluoroscopy while the HN was stimulated by a pulsed current. MAIN RESULTS: The measured impedance was 0.638 âˆ  -67.8° kΩ at 1 kHz and 5.27 âˆ  -82.1° kΩ at 100 Hz. The average values of access resistance and cut-off frequency were 0.145 kΩ and 3.98 kHz, respectively. The CSCc of the electrode was measured as 1.69 mC cm-2 at the scan rate of 1 mV s-1. The movement of the genioglossus contraction was observed under a pulsed current with an amplitude level of 0.106 mA, a rate of 0.635 kHz, and a duration of 0.375 ms applied through the MENCE. SIGNIFICANCE: A few methods to close and secure cuff electrodes have been researched, but they are associated with several drawbacks. To overcome these, we used magnetic force as a closing method of the cuff electrode. The MENCE can be precisely installed on a target nerve without any surgical techniques such as suturing or molding. Furthermore, it is convenient to remove the installed MENCE because it requires little force to detach one magnet from the other, enabling repeatable installation and removal. We anticipate that the MENCE will become a very useful tool given its unique properties as a cuff electrode for neural engineering.

Global mapping of the regulatory interactions of histone residues.

Histone residues can serve as platforms for specific regulatory function. Here we constructed a map of regulatory associations between histone residues and a wide spectrum of chromatin regulation factors based on gene expression changes by histone point mutations in Saccharomyces cerevisiae. Detailed analyses of this map revealed novel associations. Regarding the modulation of H3K4 and K36 methylation by Set1, Set2, or Jhd2, we proposed a role for H4K91 acetylation in early Pol II elongation, and for H4K16 deacetylation in late elongation and crosstalk with H3K4 demethylation for gene silencing. The association of H3K56 with nucleosome positioning suggested that this lysine residue and its acetylation might contribute to nucleosome mobility for transcription activation. Further insights into chromatin regulation are expected from this approach.