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"Nakamura, Jun"
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Visualization of the local dipole moment at the Si(111) surface using DFT calculations
A method to simulate the dipole moment mode of the scanning nonlinear dielectric microscope (SNDM) has been developed. This method has been applied to the so-called
dimer-adatom-stacking-fault (DAS) structure and a
surface with one adatom and one restatom, which are the main motifs of the DAS structure. It has been revealed that a local upward dipole moment is observed at the adatom site, consistent with the SNDM experiments. Differences in the local atomic arrangements of the adatom and restatom correlate with the amount of charge transfer between adatoms and restatoms, which varies in concert with the magnitude of the local dipole moment. This method will provide information on local dielectric properties necessary for the interpretation of various surface probe microscopy images.
Journal Article
LC3 lipidation is essential for TFEB activation during the lysosomal damage response to kidney injury
Sensing and clearance of dysfunctional lysosomes is critical for cellular homeostasis. Here we show that transcription factor EB (TFEB)—a master transcriptional regulator of lysosomal biogenesis and autophagy—is activated during the lysosomal damage response, and its activation is dependent on the function of the ATG conjugation system, which mediates LC3 lipidation. In addition, lysosomal damage triggers LC3 recruitment on lysosomes, where lipidated LC3 interacts with the lysosomal calcium channel TRPML1, facilitating calcium efflux essential for TFEB activation. Furthermore, we demonstrate the presence and importance of this TFEB activation mechanism in kidneys in a mouse model of oxalate nephropathy accompanying lysosomal damage. A proximal tubule-specific TFEB-knockout mouse exhibited progression of kidney injury induced by oxalate crystals. Together, our results reveal unexpected mechanisms of TFEB activation by LC3 lipidation and their physiological relevance during the lysosomal damage response.Nakamura et al. find that the master transcriptional regulator of lysosomal biogenesis and autophagy TFEB is activated following LC3 lipidation during lysosomal damage and show the importance of this mechanism during kidney injury.
Journal Article
Fabrication and evaluation of durable, optically clear, and self-disinfecting films
Phenoxy-substituted phthalocyanine zinc (PPcZn) was synthesized and used as a photosensitizer to prepare a variety of self-disinfecting films by incorporating it into a cellulose acetate (CA) film at various concentrations. The generation of singlet oxygen (1O2) from the films containing PPcZn irradiated with visible light was detected by a film containing 1,3-diphenylisobenzofuran (DPBF). The rate of 1O2 generation followed a pseudofirst-order kinetic model. Antiviral activity was confirmed under visible light irradiation using Bacteriophage Qβ. The film exhibited superior water resistance, photostability, mechanical strength, and sustained 1O2 production over 6 months under continuous exposure to room light. These data show the promise of this film in real-life applications as self-disinfecting surfaces.A transparent film with photoactive antiviral functions and minimal degradation over time was easily obtained by uniformly dispersing the phenoxy-substituted phthalocyanine zinc (PPcZn) in the cellulose acetate film. This film produced singlet oxygen (1O2) upon visible light irradiation, and the production capacity of 1O2 was maintained even when the film was exposed to indoor lighting for 6 months.
Journal Article
Atomic structure of the Se-passivated GaAs(001) surface revisited
We present a combined experimental and theoretical study of the Se-treated GaAs(001)-(
2
×
1
) surface. The (
2
×
1
) structure with the two-fold coordinated Se atom at the outermost layer and the three-fold coordinated Se atom at the third layer was found to be energetically stable and agrees well with the experimental data from scanning tunneling microscopy, low energy electron diffraction, and x-ray photoelectron spectroscopy. This atomic geometry accounts for the improved stability of the Se-treated surface against the oxidation. The present result allows us to address a long-standing question on the structure of the Se-passivated GaAs surface, and will leads us to a more complete understanding of the physical origin of the electrical and chemical passivation of Se-treated GaAs surface.
Journal Article
Novel scale for evaluating the therapeutic efficacy of per-oral endoscopic myotomy in achalasia
Background
Symptom scales for achalasia after per-oral endoscopic myotomy (POEM) are lacking. This study aimed to propose a new scale based on the conventional Eckardt score (c-ES) and evaluate persistent symptoms that impair patients’ quality of life (QOL) post-POEM.
Methods
Dysphagia, regurgitation, and chest pain frequencies were assessed using a 6-point scale modified-ES (m-ES) after POEM, with “occasional” symptoms on the c-ES further subdivided into three-period categories on m-ES. Symptom severity was further evaluated using a 5-point scale ranging from 1 to 5 points, with a score ≥ 3 points defined as persistent symptoms impairing QOL. We analyzed the correlation between the m-ES and severity score, diagnostic performance of the m-ES for persistent symptoms, and overlaps between each residual symptom.
Results
Overall, 536 patients (median follow-up period, 2.9 years) post-POEM were included in this multicenter study. Significant correlations were observed between the m-ES and severity scores for dysphagia (
r
= 0.67,
p
< 0.01), regurgitation (
r
= 0.73,
p
< 0.01), and chest pain (
r
= 0.85,
p
< 0.01). Twenty-six patients (4.9%) had persistent symptoms post-POEM, and 23 of them had m-ES-specific symptom frequency ≥ once a month, which was determined as the optimal frequency threshold for screening persistent symptoms. The total m-ES predicted persistent symptoms more accurately than the total c-ES (area under the curve: 0.95 vs. 0.79,
p
< 0.01). Furthermore, dysphagia and chest pain were the major residual symptoms post-POEM covering 91.4% of regurgitation.
Conclusions
The new post-POEM scale successfully evaluated the QOL-based patient symptom severities. Our study implied the possibility of a simpler scale using residual dysphagia and chest pain.
Journal Article
Impact of Computer Usage on Organizational Memory and Learning from Failure: A Case Study of a Japanese Company
Few organizations are good at learning from failure, and failures are sometimes repeated. One reason could be the inadequate functioning of organizational memory. According to previous research, IT is often assumed to complement organizational memory. However, studies have also reported that information technology weakens memory; hence, no definite conclusion has been drawn. This study aimed to identify the impact of information technology on organizational memory in the context of organizational learning from failure. We focus on a Japanese company that has successfully implemented the use of information technology for organizational learning from failure. A quantitative analysis was conducted using a questionnaire survey, which revealed the following: (1) if the matter is of high interest in the organization, it is recorded, and knowledge storage and sharing media that employ information technology are used; (2) recording activity is strengthened using knowledge storage and sharing media that employ information technology; (3) even if the matter is of high interest in the organization, it is not always possible to strengthen individual memory, but it is possible to enhance individual memory with knowledge storage/sharing media that utilize information technology; (4) knowledge storage/sharing media that utilize information technology do not directly strengthen organizational memory; and (5) knowledge storage and sharing media using information technology strengthen records and personal memory, which ultimately strengthens organizational memory.
Journal Article
Initial Clinical Outcomes of Percutaneous Full-Endoscopic Lumbar Discectomy Using an Interlaminar Approach at the L4-L5
Percutaneous full-endoscopic discectomy (PED) is being increasingly used because of its potential to minimalize soft-tissue damage and decrease hospital stay. PED using the interlaminar approach (PED-IL) at L4-L5 is performed by only a few surgeons. To the best of our knowledge, the safety and efficacy of PED-IL at L4-L5, without experience in PED via a transforaminal approach (PED-TF) has not been previously reported.
This study aimed to evaluate initial clinical outcomes and complications of PED-IL at L4-L5 without experience in PED-TF.
Retrospective evaluation.
An urban minimally invasive spine hospital.
Of a total of 50 patients (36 men and 14 women, ages ranging from 21-59 years, with the average age being 40.3 years old), 16 cases were performed at L4-L5 and 34 cases were performed at L5-S1. PED-IL was successfully completed in all cases, and no case required conversion to open surgery. The operative time, hospital stay, modified MacNab criteria, and visual analog scale (VAS) scores were examined at L5-S1 (range: 41-112). There was no significant difference in operative time between the L4-L5 and L5-S1 groups; the operative time was gradually decreased. The mean hospital stay was 2.9 days (range: 2-8 days). According to modified MacNab criteria, 20 cases (6 at L4-L5 and 14 at L5-S1) were excellent, 27 (10 at L4-L5 and 17 at L5-S1) were good, one at L5-S1 was fair, and 2 at L5-S1 were poor. Two perineurium tears occurred at L5-S1. There was no infection or recurrence of herniated nucleus pulposus (HNP). The clinical outcomes of PED-IL at L4-L5 were equal to those at L5- S1.
The mean operative time was 71.3 ± 19.3 minutes for all cases (range: 41-112 mins.),76.1 ± 16.8 minutes at L4-L5 (range: 52-102 mins.), and 70.5 ± 20.1 minutes at L5-S1 (range: 41-112 mins.).
A small sample size and a short follow-up period.
The clinical outcomes of PED-IL at L4-L5 were equal to those at L5-S1. Therefore, PED-IL is suitable to be a standard method for any type of intracanalicular disc herniation.
Journal Article
Atomic structure and passivated nature of the Se-treated GaAs(111)B surface
We have systematically studied the atomic structure and electronic properties of the Se-treated GaAs(111)B surface using scanning tunneling microscopy, reflection high-energy electron diffraction, x-ray photoelectron spectroscopy, and first-principles calculations. We have found that Se atoms substitute
3
4
monolayer of As atoms at the outermost layer of the ideal (111)B surface. Charge transfer from Se to As eliminates all of unsaturated dangling bonds, so that the surface is electronically stabilized, leaving no surface states in the mid-gap region.
Journal Article
The failure of two major formaldehyde catabolism enzymes (ADH5 and ALDH2) leads to partial synthetic lethality in C57BL/6 mice
Background
Exogenous formaldehyde is classified by the IARC as a Category 1 known human carcinogen. Meanwhile, a significant amount of endogenous formaldehyde is produced in the human body; as such, formaldehyde-derived DNA and protein adducts have been detected in animals and humans in the absence of major exogenous formaldehyde exposure. However, the toxicological effects of endogenous formaldehyde on individuals with normal DNA damage repair functions are not well understood. In this study, we attempted to generate C57BL/6 mice deficient in both
Adh5
and
Aldh2
, which encode two major enzymes that metabolize endogenous formaldehyde, in order to understand the effects of endogenous formaldehyde on mice with normal DNA repair function.
Results
Due to deficiencies in both ADH5 and ALDH2, few mice survived past post-natal day 21. In fact, the survival of pups within the first few days after birth was significantly decreased. Remarkably, two
Aldh2
−/−
/Adh5
−/−
mice survived for 25 days after birth, and we measured their total body weight and organ weights. The body weight of
Aldh2
−/−
/Adh5
−/−
mice decreased significantly by almost 37% compared to the
Aldh2
−/−
/Adh5
+/−
and
Aldh2
−/−
/Adh5
+/+
mice of the same litter. In addition, the absolute weight of each organ was also significantly reduced.
Conclusion
Mice deficient in both formaldehyde-metabolizing enzymes ADH5 and ALDH2 were found to develop partial synthetic lethality and mortality shortly after birth. This phenotype may be due to the accumulation of endogenous formaldehyde. No serious phenotype has been reported in people with dysfunctional, dominant-negative
ALDH2*2
alleles, but it has been reported that they may be highly susceptible to osteoporosis and neurodegenerative diseases. It is important to further investigate these diseases in individuals with
ALDH2*2
alleles, including an association with decreased metabolism, and thus accumulation, of formaldehyde.
Journal Article