Quantitative Analysis and Manipulation of Alkali Metal Cations at the Cathode Surface in Membrane Electrode Assembly Electrolyzers for CO2 Reduction Reactions.

The stable operation of the CO2 reduction reaction (CO2RR) in membrane electrode assembly (MEA) electrolyzers is known to be hindered by the accumulation of bicarbonate salt, which are derived from alkali metal cations in anolytes, on the cathode side. In this study, we conducted a quantitative evaluation of the correlation between the CO2RR activity and the transported alkali metal cations in MEA electrolyzers. As a result, although the presence of transported alkali metal cations on the cathode surface significantly contributes to the generation of C2+ compounds, the rate of K+ ion transport did not match the selectivity of C2+, suggesting that a continuous supply of high amount of K+ to the cathode surface is not required for C2+ formation. Based on these findings, we achieved a faradaic efficiency (FE) and a partial current density for C2+ of 77% and 230 mA cm-2, respectively, even after switching the anode solution from 0.1 M KHCO3 to a dilute K+ solution (<7 mM). These values were almost identical to those when 0.1 M KHCO3 was continuously supplied. Based on this insight, we successfully improved the durability of the system against salt precipitation by intermittently supplying concentrated KHCO3, compared with the continuous supply.

Inhibition of non-homologous end joining mitigates paclitaxel resistance resulting from mitotic slippage in non-small cell lung cancer.

Mitotic slippage, which enables cancer cells to bypass cell death by transitioning from mitosis to the G1 phase without undergoing normal cytokinesis, is one likely mechanism of paclitaxel (PTX) resistance. DNA double-strand breaks (DSBs) in the G1 phase are mainly repaired through non-homologous end joining (NHEJ). Therefore, inhibiting NHEJ could augment the PTX-induced cytotoxicity by impeding the repair of PTX-induced DSBs during the G1 phase following mitotic slippage. We aimed to evaluate the effects of NHEJ inhibition on mitotic slippage after PTX treatment in non-small cell lung cancer (NSCLC). H1299, A549, H1975, and H520 NSCLC cell lines were employed. In addition, A-196 and JQ1 were used as NHEJ inhibitors. H1299 cells were PTX-resistant and exhibited an increased frequency of mitotic slippage upon PTX treatment. NHEJ inhibitors significantly augmented the PTX-induced cytotoxicity, DSBs, and apoptosis in H1299 cells. The newly generated PTX-resistant cells were even more prone to mitotic slippage following PTX treatment and susceptible to the combined therapy. Docetaxel further demonstrated synergistic effects with the NHEJ inhibitor in PTX-resistant cells. NHEJ inhibition may overcome intrinsic or acquired PTX resistance resulting from mitotic slippage by synergistically increasing the cytotoxic effects of antimitotic drugs in NSCLC.

Tuning the odd-even effect on two-dimensional assemblies of curcumin derivatives by alkyl chain substitution: a scanning tunnelling microscopy study.

Well-ordered molecular arrangement on surfaces is fundamental for fabrication of functional molecular devices which are of particular interest in nanotechnology. In addition to nano-manufacturing, the production of useful materials from natural resources has recently attracted increasing attention. Herein, we focused on the two-dimensional (2D) self-assemblies of curcumin derivatives. The effects of the number, length, and substitution of the alkyl chains on the 2D structures of curcumin derivatives were studied by scanning tunnelling microscopy at the highly oriented pyrolytic graphite/1,2,4-trichlorobenzene interface. Curcumin derivatives containing both methoxy and alkoxy chain groups and those possessing four alkoxy chains exhibit linear structures with and without interdigitation of alkoxy chains, respectively. These 2D structure formations are independent of the alkyl chain length. However, the bisdemethoxycurcumin derivatives periodically form stair-like and linear structures depending on the alkyl chain length, which indicates the existence of the odd-even effect. These results suggest that the 2D structural modulation of curcumin derivatives caused by the odd-even effect can be tuned by the number of alkyl chain substituents. The appearance and disappearance of the odd-even effect in curcumin derivatives are discussed in terms of the balance between intermolecular and molecule-substrate interactions.

Real-world data on the efficacy and safety of immune-checkpoint inhibitors in elderly patients with non-small cell lung cancer.

PURPOSE: Immune-checkpoint inhibitors (ICIs) are effective against advanced non-small cell lung cancer (NSCLC). However, whether the efficacy and safety of ICI treatment in elderly patients are similar to those in younger patients is unclear. This study was designed to address this question. METHODS: We enrolled patients who received ICI monotherapy in Japan between December 2015 and December 2017; those ≥75 years of age comprised the elderly group. We compared the efficacy and safety of ICI monotherapy in elderly patients with those in younger patients and explored prognostic factors in elderly patients. RESULTS: We enrolled 676 patients; 137 (20.3%) were assigned to the elderly group. The median age of the elderly and younger groups was 78 (range, 75-85) and 66 (range, 34-74) years. The median progression-free survival (4.8 months vs. 3.3 months, p = 0.1589) and median overall survival (12.3 months vs. 13.0 months, p = 0.5587) were similar between the elderly and younger groups. Multivariate analysis revealed that a significantly better OS in the elderly group was associated with better responses to first- or second-line ICI treatment (p = 0.011) and more immune-related adverse events (irAEs) (p = 0.02). IrAEs that led to ICI discontinuation occurred in 34 of 137 patients (24.8%) in the elderly group, and their survival was significantly higher than that in those who did not have irAEs. CONCLUSION: ICI is also effective in elderly NSCLC patients, and treatment discontinuation due to irAEs may be a good prognostic marker.

Inorganic salt-assisted assembly of anionic π-conjugated rings enabling 7Li NMR-based evaluation of antiaromaticity.

The 1H NMR-based estimation of antiaromaticity in anionic molecules is challenging because of the difficulty in separately evaluating NMR shielding effects due to paratropic ring currents and negative charges. Herein we propose a novel approach for the 7Li NMR-based evaluation of antiaromaticity enabled by inorganic salt-assisted clusterization, which is serendipitously found during our studies on hyperconjugative antiaromaticity. Reduction of a dibenzo[b,f]silepin (1) with lithium afforded the dilithium salt [(Li+)2(thf)5][12-] (2), which is expected to have antiaromatic character with a pseudo-16π-electron system involving hyperconjugation between the anionic π-clouds and the σ*(Si-Me) orbitals, although the evaluation of its antiaromaticity by NMR was difficult. Compound 2 reacted with 0.2 equivalents of O2 gas to form a trimeric cluster [(Li+)(solv.)n][(12-)3(Li9O25+)] (3), which can be understood as a supramolecular complex composed of three molecules of [Li+]2[12-] and two Li2O salts. X-ray diffraction analysis revealed that the [Li9O2]5+ core is surrounded by three dibenzosilepinyl dianions (12-), with multiple Li-π coordinations. The trimeric structure is maintained in a toluene solution according to the 1H and 7Li{1H} NMR spectra, and of particular interest are the significant downfield shifts of 7Li{1H} NMR signals of the Li9O2 core (δ(7Li) = 6.3, 4.4). These explicit downfield shifts are reasonably explained by the paratropic ring currents of the dianionic dibenzosilepin rings, which was supported by theoretical studies.

Halogen bond-directed self-assembly in bicomponent blends at the solid/liquid interface: effect of the alkyl chain substitution position.

The fabrication of well-organised molecular assemblies on surfaces is fundamental for the creation of functional molecular systems applicable to nanoelectronic and molecular devices. In this study, we investigated the effect of substitution positions of alkyl chains on the formation of halogen-bonded molecular networks. For this purpose, building blocks with different head groups (i.e., pyridine (Py) or tetrafluoro-iodobenzene (FI)) were substituted with hexadecyloxy chains at either the 3,4- or the 3,5-positions. The two-dimensional assembly of each compound as a single-component system was studied using scanning tunnelling microscopy (STM) at the highly oriented pyrolytic graphite (HOPG)/1-phenyloctane interface. All compounds displayed linear structures in which the alkyl chains were aligned along one of the HOPG axes. In the exceptional case of FI bearing hexadecyloxy chains at the 3,5-positions (denoted as FI-3,5), hexagonal arrays were tentatively formed owing to the triangular molecular arrangement induced by halogen bonding. A bicomponent blend of Py-3,4/FI-3,5 (1 : 1 molar ratio) enabled the formation of a honeycomb structure, whereas that of Py-3,5/FI-3,4 (1 : 1 molar ratio) produced a rectangular assembly that was periodically arranged in a zig-zag fashion. Finally, based on the observed blend ratio dependence, the formation of these different two-dimensional structures by variation in the substitution positions of the alkyl chains was discussed in terms of molecule-molecule and molecule-substrate interactions.

Efficacy of Pseudo-Ceramide-Containing Steroid Lamellar Cream in Patients with Mild to Moderate Atopic Dermatitis: A Randomized, Double-Blind Study.

INTRODUCTION: Atopic dermatitis (AD) is a chronic inflammatory skin disorder involving decreased barrier function of the stratum corneum. This decrease, caused by a reduction in ceramide, the primary component of intercellular lipids in the stratum corneum, leads to a disturbance in the lamellar structure. METHODS: We developed a formulation (test cream) containing a steroid and synthetic pseudo-ceramide (SLE: N-(3-hexadecyloxy-2-hydroxypropyl)-N-2-hydroxyethyl hexadecanamide) that forms a lamellar structure on the skin after its application and drying. The formulation or control cream (a formulation containing a steroid but not pseudo-ceramide that does not form a lamellar structure) was applied twice daily for 2 weeks to the lesional area of 34 participants with mild to moderate AD symptoms. RESULTS: The test cream showed a periodic structure with an interface space of approximately 8.2 nm in transmission electron microscopy and small- and wide-angle X-ray scattering, similar to the lamellar structure in the human stratum corneum. In the double-blind test, the anti-inflammatory effects of the test cream (n = 17) were comparable to those of the control cream (n = 17). In the test cream group, a significant increase in the stratum corneum moisture content (p < 0.01) and significant decrease in transepidermal water loss (p < 0.05) were observed at weeks 1 and 2 after application compared with those before application. No such change was observed in the control group. CONCLUSION: The results indicate that, even with a relatively short application period of 2 weeks, the test cream not only suppressed inflammation of the lesional area, but also improved the inherent barrier function of the stratum corneum, suggesting its potential as a treatment option for patients with AD.

Efficacy of Heparinoid Cream Containing Pseudo-Ceramide for Remission of Atopic Dermatitis.

PURPOSE: Atopic dermatitis (AD) is characterized by chronic inflammation, which frequently recurs, is exacerbated, and enters remission. A maintenance remission period is important for AD patients. We developed a formulation for use during AD remission, containing heparinoid and pseudo-ceramide that forms a lamellar structure. We evaluated the allergen permeability and examined the formulation's efficacy in maintaining remission in patients with AD. MATERIALS AND METHODS: Seventeen AD patients applied a cream containing 0.3% heparinoid and pseudo-ceramide (test cream group, n = 10), or a general cream containing 0.3% heparinoid (control cream group, n = 7) to their arm for four weeks after inducing remission with the application of a steroid cream for two weeks. RESULTS: The lamellar structure of the test cream was confirmed with small- and wide-angle x-ray scattering analysis and observation by transmission electron microscopy. The test cream inhibited the penetration of V8 protease significantly compared to the control cream in vitro. According to AD severity score by dermatologists, the effects remission maintenance of the test cream group were comparable to those of the control cream group. However, the test cream group had a significantly increased skin hydration value compared to the control cream group. A significant decrease in transepidermal water loss, an indicator of skin barrier function, was shown in the test cream group compared to the control cream group. CONCLUSION: The cream with lamellar structures containing heparinoid and pseudo-ceramides may inhibit allergen penetration. Moreover, skin properties improved during the remission period; thus, the formulation we developed was suitable for use during the AD remission period.

A new strategy for hyperconjugative antiaromatic compounds utilizing negative charges: a dibenzo[b,f]silepinyl dianion.

Herein we propose a new strategy for hyperconjugative antiaromatic compounds utilizing negative charges and design the 5,5-diphenyldibenzo[b,f]silepinyl dianion (pseudo 16π-electron system) in which negative hyperconjugation occurs between the anionic π-cloud and the σ*(Si-Ph) orbital. Essentially, reduction of the dibenzo[b,f]silepin with lithium readily generated a dilithium salt of the dibenzosilepinyl dianion, and its hyperconjugative antiaromaticity has been evidenced by the upfield shifts of 1H NMR signals and theoretical calculations, including large NICSzz values and ACID plots.

Limonoids and unsaturated fatty acids present in Melia toosendan increase ceramide production in keratinocytes.

The skin barrier prevents moisture evaporation and the entry of foreign substances such as allergens. Ceramides are one of the most important factors for maintaining skin barrier function. Melia toosendan is a plant of the Meliaceae family, and its fruit extracts have been used in Traditional Chinese Medicine as analgesics and anthelmintics; however, its ability to increase ceramide levels has not been reported. In this study, we screened for compounds present in M. toosendan fruit extracts that increase ceramide levels in the skin. We fractionated the extracts based on their activity to identify the active components. Nimbolinins, limonoids such as toosendanin, and hydroxylated unsaturated fatty acids were found to be the major active components. The structure-activity relationship of toosendanin derivatives indicated that the sites around R4 and R5 contributed to the activity. To the best of our knowledge, this is the first report showing that limonoids promote ceramide production in skin cells. Therefore, M. toosendan fruit extracts may be used to develop products for improving the skin barrier function.

Prognostic factors in patients with advanced non-small cell lung cancer after long-term Anti-PD-1 therapy (HOT1902).

OBJECTIVES: Limited information is available on the appropriate treatment duration of immune checkpoint inhibitors (ICIs). We aimed to identify candidates who would benefit from ICI discontinuation after one year of treatment for metastatic non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: This retrospective multi-institutional observational study examined medical records of all consecutive patients with advanced or recurrent NSCLC, who started ICI monotherapy at 15 institutions in Japan between December 2015 and December 2017. Patients who received initial ICI therapy for >1 year without progressive disease were defined as the long-term treatment (LT) group; others were defined as the non-long-term treatment (NLT) group. Primary outcomes included the prognostic factors in the LT group, whereas secondary outcomes included efficacy of ICI rechallenge, safety, and survival outcomes in the overall population. RESULTS: In total, 676 patients were enrolled, and 114 (16.9 %) were assigned to the LT group. The median time interval from the start of initial ICI administration to data cutoff was 34.3 months (range, 24.1-47.8); thus, all surviving patients were followed-up for at least 2 years from the start of initial ICI. Median progression-free survival (PFS) was longer in the LT than in the NLT group (33.6 months vs. 2.7 months; p < 0.001). On multivariate analysis, significantly better PFS was associated with smoking (hazard ratio [HR]=0.36, p = 0.04), and complete response (CR; HR=uncomputable, p < 0.001) in the LT group. Thirty-seven patients (5.5 %) received ICI rechallenge, including 10 in the LT group. Among patients receiving rechallenge treatment, the median PFS was 2.2 months, with no difference between the LT and NLT groups. CONCLUSIONS: In the LT group, smoking and achieving CR were significantly associated with better PFS. Since rechallenge treatment was not effective, careful consideration is required for discontinuing ICI. However, these prognostic factors are helpful in considering candidates for ICI discontinuation. TRIAL REGISTRATION: UMIN ID, UMIN000041403.

A case of radio-insensitive SMARCA4-deficient thoracic undifferentiated carcinoma with severe right heart failure.

SMARCA4-deficient thoracic sarcomatoid tumors were characterized by inactivating mutations of SMARCA4 and often found in the chest of young and middle-aged males with a smoking history. Recently, SMARCA4-deficient thoracic sarcomatoid tumors were reported to represent primarily smoking-associated undifferentiated/de-differentiated carcinomas rather than primary thoracic sarcomas. The main complication of this tumor is compression of the respiratory tract and/or blood vessels. A 39-year-old man presented with a 2-month history of fever and dyspnea. Computed tomography revealed a mediastinal tumor invading the right and left pulmonary arteries. Because of severe right heart failure, we considered him ineligible for bronchoscopy. We scheduled palliative irradiation with 40 Gy/20 Fr to improve hemodynamics and perform endobronchial ultrasound transbronchial needle aspiration later. However, irradiation was ineffective, and his general condition deteriorated quickly and he died after a 7-week hospitalization. An autopsy revealed that the diagnosis was SMARCA4-deficient thoracic undifferentiated carcinoma. It has been reported that this tumor is insensitive to radiotherapy and there were some cases which responded to an immune checkpoint inhibitor. Therefore, when caring for patients with mediastinal tumors that invade and compress the trachea and large vessels, it is important to consider this tumor as a differential diagnosis and try to make a pathological diagnosis as soon as possible.

Impact of lung density on isolated lung tumor dose in VMAT using inline MR-Linac.

PURPOSE: This study investigated the impact of lung density on the isolated lung tumor dose for volumetric modulated arc therapy (VMAT) in an inline magnetic resonance linear accelerator (MR-Linac) using the Monte Carlo (MC) simulation. METHODS: CT images of the thorax phantoms with lung tumors of 1, 2, and 3 cm diameters were converted into voxel-base phantoms with lung densities of 0.1, 0.2, and 0.3 g/cm3, respectively. The dose distributions were calculated for partial-arc VMAT. The dose distributions were compared using dose differences, dose volume histograms, and dose volume indices. RESULTS: In all cases, the inline magnetic field significantly enhanced the lung tumor dose compared to that at 0 T. For the 1 cm lung tumor, the inline magnetic field of 1 T increased the minimum dose of 95% of the Planning target volume (PTV D95) by 14.0% in 0.1 g/cm3 lung density as compared to that in 0.3 g/cm3 at 0 T. In contrast, at 0 and 0.5 T, the PTV D95 in 0.3 g/cm3 lung density was larger than that in lung density of 0.1 g/cm3. For the 2 cm lung tumor, a similar tendency to 1 cm was observed, whereas the dose impact of lung density was smaller than that for 1 cm. For the 3 cm lung tumor, the lung tumor dose was independent of lung density at 0.5 T and 1.0 T. CONCLUSION: The inline MR-Linac with the magnetic field over 1 T can enhance the PTV D95 for VMAT regardless of the lung density.

Impact of transverse magnetic fields on dose response of a nanoDot OSLD in megavoltage photon beams.

PURPOSE: We investigated the impact of transverse magnetic fields on the dose response of a nanoDot optically stimulated luminescence dosimetry (OSLD) in megavoltage photon beams. METHODS: The nanoDot OSLD response was calculated via Monte Carlo (MC) simulations. The responses RQ and RQ,B without and with the transverse magnetic fields of 0.35-3 T were analyzed as a function of depth at a 10 cm × 10 cm field for 4-18 MV photons in a solid water phantom. All responses were determined based on comparisons with the response under the reference conditions (depth of 10 cm and a 10 cm × 10 cm field) for 6 MV without the magnetic field. In addition, the influence of air-gaps on the nanoDot response in the magnetic field was estimated according to Burlin's general cavity theory. RESULTS: The RQ as a function of depth for 4-18 MV ranged from 1.013 to 0.993, excepting the buildup region. The RQ,B increased from 2.8% to 1.5% at 1.5 T and decreased from 3.0% to 1.1% at 3 T in comparison with RQ as the photon energy increased. The depth dependence of RQ,B was less than 1%, excepting the buildup region. The top air-gap and the bottom air- gap were responsible for the response reduction and the response increase, respectively. CONCLUSIONS: The response RQ,B varied depending on the magnetic field intensity, and the variation of RQ,B reduced as the photon beam energy increased. The air-gaps affected the dose deposition in the magnetic fields.

Impact of transverse magnetic fields on dose response of a radiophotoluminescent glass dosimeter in megavoltage photon beams.

PURPOSE: The purpose of this study was to investigate the impact of transverse magnetic fields on the dose response of a radiophotoluminescent glass dosimeter (RGD) in megavoltage photon beams. METHODS: The RGD relative response (i.e., RGD dose per absorbed dose to water at the midpoint of the detector in the absence of the detector) was calculated using Monte Carlo (MC) simulations. Note that the Monte Carlo calculations do not account for changes of the signal production per unit dose to the RGD caused by the magnetic field strength. The relative energy response RQ , the relative magnetic response RB , and the relative overall response RQ , B with the transverse magnetic fields of 0-3 T were analyzed as a function of depth, for a 10 cm × 10 cm field in a solid water phantom, for 4-18 MV photons. Although magnetic resonance (MR) linacs with flattening filter free beams are commercially available, flattening filter beams were used to investigate the RGD response in this study. RQ is the response in beam quality Q relative to that in the reference beam with quality 6 MV, RB is the response in beam quality Q with the magnetic field relative to that in beam quality Q without the magnetic field, and the RQ,B is the response in beam quality Q with the magnetic field relative to that in the reference beam with quality 6 MV without the magnetic field. Two RGD orientations were considered: RGD long axis is parallel (direction A) and perpendicular (direction B) to the magnetic field. The reference irradiation conditions were at the depth of 10 cm for a 10 cm × 10 cm field for 6 MV, without the magnetic field. In addition, the influence of a small air-gap between the holder inner wall and the RGD on the dose response in the magnetic field, Rgap , was analyzed in detail. Rgap is the response in beam quality Q without/with the air-gap. RESULTS: RQ decreased by up to 2.7% as the energy increased in the range of 4-18 MV, except in the buildup region. In direction A, the variation of RB owing to the magnetic field strength was below 1.0%, regardless of the photon energy. In contrast, in direction B, RB decreased with increasing magnetic field strength and decreased up to 4.0% at 3 T for 10 MV. The Rgap for 0.03 and 0.05 cm air-gap models in direction A decreased up to 2.3% and up to 4.0%, respectively. CONCLUSIONS: The variation of RQ,B changed with the direction of the RGD relative to the magnetic field. For dose measurements, RGDs should be positioned with the long axis parallel to the magnetic field, without air-gaps.

Design and characteristics of an agar additive polymer gel dosimeter.

Herein, we investigate the use of agar and gelatin in a polymer gel dosimeter. The polymer gel is enclosed in a vinyl film to obtain a dosimeter of arbitrary shape and maintain the shape at room temperature. The resulting polymer gel dosimeter could preserve its shape across a wide temperature range. Excluding the surface region, the obtained dose distribution was within 3% of that determined in an ionization chamber.

Mode of Action of GH30-7 Reducing-End Xylose-Releasing Exoxylanase A (Xyn30A) from the Filamentous Fungus Talaromyces cellulolyticus.

In this study, we characterized the mode of action of reducing-end xylose-releasing exoxylanase (Rex), which belongs to the glycoside hydrolase family 30-7 (GH30-7). GH30-7 Rex, isolated from the cellulolytic fungus Talaromyces cellulolyticus (Xyn30A), exists as a dimer. The purified Xyn30A released xylose from linear xylooligosaccharides (XOSs) 3 to 6 xylose units in length with similar kinetic constants. Hydrolysis of branched, borohydride-reduced, and p-nitrophenyl XOSs clarified that Xyn30A possesses a Rex activity. 1H nuclear magnetic resonance (1H NMR) analysis of xylotriose hydrolysate indicated that Xyn30A degraded XOSs via a retaining mechanism and without recognizing an anomeric structure at the reducing end. Hydrolysis of xylan by Xyn30A revealed that the enzyme continuously liberated both xylose and two types of acidic XOSs: 22-(4-O-methyl-α-d-glucuronyl)-xylotriose (MeGlcA2Xyl3) and 22-(MeGlcA)-xylobiose (MeGlcA2Xyl2). These acidic products were also detected during hydrolysis using a mixture of MeGlcA2Xyl n (n = 2 to 14) as the substrate. This indicates that Xyn30A can release MeGlcA2Xyl n (n = 2 and 3) in an exo manner. Comparison of subsites in Xyn30A and GH30-7 glucuronoxylanase using homology modeling suggested that the binding of the reducing-end residue at subsite +2 was partially prevented by a Gln residue conserved in GH30-7 Rex; additionally, the Arg residue at subsite -2b, which is conserved in glucuronoxylanase, was not found in Xyn30A. Our results lead us to propose that GH30-7 Rex plays a complementary role in hydrolysis of xylan by fungal cellulolytic systems.IMPORTANCE Endo- and exo-type xylanases depolymerize xylan and play crucial roles in the assimilation of xylan in bacteria and fungi. Exoxylanases release xylose from the reducing or nonreducing ends of xylooligosaccharides; this is generated by the activity of endoxylanases. ß-Xylosidase, which hydrolyzes xylose residues on the nonreducing end of a substrate, is well studied. However, the function of reducing-end xylose-releasing exoxylanases (Rex), especially in fungal cellulolytic systems, remains unclear. This study revealed the mode of xylan hydrolysis by Rex from the cellulolytic fungus Talaromyces cellulolyticus (Xyn30A), which belongs to the glycoside hydrolase family 30-7 (GH30-7). A conserved residue related to Rex activity is found in the substrate-binding site of Xyn30A. These findings will enhance our understanding of the function of GH30-7 Rex in the cooperative hydrolysis of xylan by fungal enzymes.

Structural and functional characterization of a bifunctional GH30-7 xylanase B from the filamentous fungus Talaromyces cellulolyticus.

Glucuronoxylanases are endo-xylanases and members of the glycoside hydrolase family 30 subfamilies 7 (GH30-7) and 8 (GH30-8). Unlike for the well-studied GH30-8 enzymes, the structural and functional characteristics of GH30-7 enzymes remain poorly understood. Here, we report the catalytic properties and three-dimensional structure of GH30-7 xylanase B (Xyn30B) identified from the cellulolytic fungus Talaromyces cellulolyticus Xyn30B efficiently degraded glucuronoxylan to acidic xylooligosaccharides (XOSs), including an α-1,2-linked 4-O-methyl-d-glucuronosyl substituent (MeGlcA). Rapid analysis with negative-mode electrospray-ionization multistage MS (ESI(-)-MS n ) revealed that the structures of the acidic XOS products are the same as those of the hydrolysates (MeGlcA2Xyl n , n > 2) obtained with typical glucuronoxylanases. Acidic XOS products were further degraded by Xyn30B, releasing first xylobiose and then xylotetraose and xylohexaose as transglycosylation products. This hydrolase reaction was unique to Xyn30B, and the substrate was cleaved at the xylobiose unit from its nonreducing end, indicating that Xyn30B is a bifunctional enzyme possessing both endo-glucuronoxylanase and exo-xylobiohydrolase activities. The crystal structure of Xyn30B was determined as the first structure of a GH30-7 xylanase at 2.25 Å resolution, revealing that Xyn30B is composed of a pseudo-(α/ß)8-catalytic domain, lacking an α6 helix, and a small ß-rich domain. This structure and site-directed mutagenesis clarified that Arg46, conserved in GH30-7 glucuronoxylanases, is a critical residue for MeGlcA appendage-dependent xylan degradation. The structural comparison between Xyn30B and the GH30-8 enzymes suggests that Asn93 in the ß2-α2 loop is involved in xylobiohydrolase activity. In summary, our findings indicate that Xyn30B is a bifunctional endo- and exo-xylanase.

Light-Induced Reworkable Adhesives Based on ABA-type Triblock Copolymers with Azopolymer Termini.

Photocurable adhesives based on polymers and resins are an integral part of different production processes because of their fast curing and local area bonding ability. Recently, dismantlable adhesives have attracted a lot of attention for recycling adherends or replacement of adhesion defects. However, adhesives that allow repeatable bonding and debonding solely by light irradiation, i.e., without heat activation, are lacking. Here, ABA-type triblock copolymers consisting of poly(meth)acrylates bearing an azobenzene moiety (A block) and 2-ethylhexyl (B block) side chains were synthesized and utilized as photocurable adhesives. In contrast to the azo homopolymers, the block copolymer structure and incorporation of the soft middle block actualized a low concentration of the azobenzene moiety and consequently, higher flexibility of the resultant copolymers. This enabled film formation of the azobenzene-based adhesives and light-induced bonding for the first time. On the basis of the photoisomerization of the azobenzene moiety, changes in their viscoelastic property, i.e., softening and hardening, were induced by UV irradiation at 365 nm (50-100 mW cm-2) and green light irradiation at 520 nm (40 mW cm-2), respectively. In fact, two glass substrates were bonded with the self-standing polymer film, which was sequentially softened and hardened upon UV and green light irradiations. They exhibited shear strengths of 1.5-2.0 MPa, and UV irradiation lowered the adhesion strength to 0.5-0.1 MPa. Interestingly, the repeatable bonding and debonding abilities of the polymers were accomplished without loss of the adhesion strength.

Myasthenic Crisis Complicated with Myxedema, Positive for Both Anti-acetylcholine Receptor and Anti-muscle-specific Tyrosine Kinase Antibodies.

We herein report the case of myasthenic crisis occurring in a 51-year-old man. He had experienced ptosis, increased body weight with edema, and fatigue with dyspnea. He presented at our emergency department with disturbed consciousness. He was originally diagnosed with myxedema coma, and he required artificial respiration. Because his weakness persisted and he was positive for anti-acetylcholine receptor antibodies and anti-muscle-specific tyrosine kinase antibodies, we diagnosed myasthenic crisis after various examinations. His clinical response to treatment was good and he was discharged in an ambulatory status 3 months after admission. This case demonstrates that myasthenic crisis may occur in association with myxedema.