Directed Evolution of a Cp*RhIII-Linked Biohybrid Catalyst Based on a Screening Platform with Affinity Purification

Directed evolution of Cp*Rh^III-linked nitrobindin (NB), a biohybrid catalyst, was performed based on an in vitro screening approach. A key aspect of this effort was the establishment of a high-throughput screening (HTS) platform that involves an affinity purification step employing a starch-agarose resin for a maltose binding protein (MBP) tag. The HTS platform enables efficient preparation of the purified MBP-tagged biohybrid catalysts in a 96-well format and eliminates background influence of the host E. coli cells. Three rounds of directed evolution and screening of more than 4000 clones yielded a Cp*Rh^III-linked NB(T98H/L100K/K127E) variant with a 4.9-fold enhanced activity for the cycloaddition of acetophenone oximes with alkynes. It is confirmed that this HTS platform for directed evolution provides an efficient strategy for generating highly active biohybrid catalysts incorporating a synthetic metal cofactor.     

Possibility of Japanese Cedar Pollen Causing False Positives in the Deep Mycosis Test

Because Japanese cedar pollen (JCP) contains beta-1,3-d-glucan (BG), there is concern that its lingering presence in the atmosphere, especially during its scattering period, may cause false positives in the factor-G-based Limulus amebocyte lysate (LAL) assay used to test for deep mycosis (i.e., G-test). Hence, we examined whether the LAL assay would react positively with substances contained in JCP by using the G-test to measure JCP particles and extracts. BG was purified from the JCP extract on a BG-specific affinity column, and the percentage extractability was measured using three different BG-specific quantitative methods. The G-test detected 0.4 pg BG in a single JCP particle and 10 fg from a single particle in the extract. The percentage extractability of JCP-derived BG was not significantly different among the three quantitative methods. As the JCP particles should technically have been removed during serum separation, they should be less likely to be a direct false-positive factor. However, given that the LAL-assay-positive substances in the JCP extract were not distinguishable by the three BG-specific quantitative methods, we conclude that they may cause the background to rise. Therefore, in Japan false positives arising from JCP contamination should be considered when testing patients for deep mycosis.     

Experimental investigation of structure vulnerabilities to firebrand showers

Attempting to experimentally quantify the vulnerabilities of structures to ignition from firebrand showers has remained elusive. The coupling of two facilities has begun to unravel this difficult problem. The NIST Firebrand Generator (NIST Dragon) is an experimental device that can generate a firebrand shower in a safe and repeatable fashion. Since wind plays a critical role in the spread of WUI fires in the USA and urban fires in Japan, NIST has established collaboration with the Building Research Institute (BRI) in Japan. BRI maintains one of the only full scale wind tunnel facilities in the world designed specifically for fire experimentation; the Fire Research Wind Tunnel Facility (FRWTF). The present investigation is aimed at extensively quantifying firebrand penetration through building vents using full scale tests. A structure was placed inside the FRWTF and firebrand showers were directed at the structure using the NIST Dragon. The structure was fitted with a generic building vent, consisting of only a frame fitted with a metal mesh. Six different mesh sizes openings were used for testing. Behind the mesh, four different materials were placed to ascertain whether the firebrands that were able to penetrate the building mesh assembly could ignite these materials. Reduced scale test methods afford the capability to test new vent technologies and may serve as the basis for new standard testing methodologies. As a result, a new experimental facility developed at NIST is presented and is known as the NIST Dragon's LAIR (Lofting and Ignition Research). The NIST Dragon's LAIR has been developed to simulate a wind driven firebrand attack at reduced scale. The facility consists of a reduced scale Firebrand Generator (Baby Dragon) coupled to a bench scale wind tunnel. Finally, a series of full scale experiments were conducted to visualize the flow of firebrands around obstacles placed downstream of the NIST Dragon. Firebrands were observed to accumulate in front of these obstacles at a stagnation plane, as was observed when the structure was used for firebrand penetration through building vent experiments, due to flow recirculation. The accumulation of firebrands at a stagnation plane presents a severe threat to ignitable materials placed near structures.     

Production of Gentiobiose from Hydrothermally Treated Aureobasidium pullulans β-1,3-1,6-Glucan

We report production of the functional disaccharide gentiobiose β-D-Glcp-(1→6)-D-Glc by a hydrolysis reaction of hydrothermally treated Aureobasidium pullulans β-1,3-1,6-glucan as the substrate and Kitalase as the enzyme. Gentiobiose was produced over the pH range 4−6 and the concentration of gentiobiose produced decreased above pH 7. The maximum value of gentiobiose production was unaffected by the enzyme concentration. The maximum concentration of gentiobiose produced was dependent on the substrate concentration whereas the maximum ratio of gentiobiose to glucose was not. The production of gentiobiose from yeast β-1,3-1,6-glucan was lower than that from A. pullulans β-1,3-1,6-glucan.     

Enantioselective addition Of diketene to aldehydes promoted by chiral schiff base—titanium alkoxide complex. Application to asymmetric synthesis of potential inhibitors of HMG coenzyme reductase

Highly enantioselective addition of diketene to aldehydes was achieved by using novel Schiff base—titanium alkoxide complexes. Up to 92% ee of 5-hydroxy-3-oxoesters was obtained. This procedure provides an efficient method for the asymmetric synthesis of potential inhibitors of HMG coenzyme reductase.     

Mechanism of Magnetite Seam Formation and its Role for FeO Scale Transformation

The phase transformation behavior of a thermally grown oxide scale of FeO on pure-Fe and an Fe–2wt%Au alloy was investigated. Particular attention was paid to formation of a magnetite seam, which is the Fe₃O₄ layer formed at the FeO/alloy interface at an initial stage of the phase transformation, since it has important effects on the overall phase transformation of FeO scale. A thin Au(Fe) layer was found to develop on the Fe–Au alloy at the FeO/alloy interface after 32 min of oxidation at 750 °C in air. This Au(Fe) layer prevented formation of a magnetite seam and accelerated the FeO eutectoid reaction. The Au(Fe) layer acted as a “chemical diffusion barrier” for inward diffusion of Fe from the FeO to the alloy substrate across the FeO/alloy interface and prevented magnetite seam formation.     

Molecular Depolymerization of Moist Sweet Potato Starch Melt by Shearing Force under an Elevated Temperature

Sweet potato starch (SPS) with 20 or 25% moisture was heated and then fused at 150°C for 15 min under pressurization at 30–500 Kg/cm². At the same time, the heated SPS melt was extruded through a capillary tube under specified pressure in order to give shearing force. Thus, intact SPS, heated SPS and heated sheared SPS specimen were prepared and examined. The heated and heated sheared SPS did not contain any pyrolysis products because their spectrum profiles were the same as that of intact SPS. By heating and shearing, the intact SPS molecule was depolymerized into small molecules including a few amount of glucose. This finding was revealed by means of molecular weight estimation by viscometry and by gel filtration. The shearing toward SPS melt markedly stimulated the depolymerization while the effect of only heating on depolymerization of SPS was modulate in comparison with heated shearing. Water solubilities of intact SPS, heated SPS and heated sheared SPS with 20% moisture were 0.07, 3.5 and 51.5% respectively, and also the degrees of gelatinization of 1.8% for intact starch increased markedly to 29% for heated SPS and 80–95% (depending on the pressure at extrusion) for heated sheared SPS.     

Therapeutic Targets and Emerging Treatments in Advanced Chondrosarcoma

Simple SummaryChondrosarcomas develop chemoresistance to standard anticancer drugs, making it difficult to control unresectable or metastatic chondrosarcomas. To improve the clinical outcomes of chondrosarcoma, new treatment approaches, such as molecule-targeting agents and immunotherapy, are needed. Recent research has revealed promising biomarkers and therapeutic targets for chondrosarcoma. In addition, several molecule-targeting agents have shown favorable antitumor activities in several clinical studies in patients with advanced sarcomas, including chondrosarcoma. This review summarizes recent basic studies on biomarkers and therapeutic targets and recent clinical studies on treating chondrosarcomas.AbstractDue to resistance to standard anticancer agents, it is difficult to control the disease progression in patients with metastatic or unresectable chondrosarcoma. Novel therapeutic approaches, such as molecule-targeting drugs and immunotherapy, are required to improve clinical outcomes in patients with advanced chondrosarcoma. Recent studies have suggested several promising biomarkers and therapeutic targets for chondrosarcoma, including IDH1/2 and COL2A1. Several molecule-targeting agents and immunotherapies have shown favorable antitumor activity in clinical studies in patients with advanced chondrosarcomas. This review summarizes recent basic studies on biomarkers and molecular targets and recent clinical studies on the treatment of chondrosarcomas.     

Liquid‐phase sintering of highly Na+ ion conducting Na3Zr2Si2PO12 ceramics using Na3BO3 additive

Na₃Zr₂Si₂PO₁₂ (NASICON) is a promising material as a solid electrolyte for all‐solid‐state sodium batteries. Nevertheless, one challenge for the application of NASICON in batteries is their high sintering temperature above 1200°C, which can lead to volatilization of light elements and undesirable side reactions with electrode materials at such high temperatures. In this study, liquid‐phase sintering of NASICON with a Na₃BO₃ (NBO) additive was performed for the first time to lower the NASICON sintering temperature. A dense NASICON‐based ceramic was successfully obtained by sintering at 900°C with 4.8 wt% NBO. This liquid‐phase sintered NASICON ceramic exhibited high total conductivity of ~1 × 10^?3 S cm^?1 at room temperature and low conduction activation energy of 28 kJ mol^?1. Since the room‐temperature conductivity is identical to that of conventional high‐temperature‐sintered NASICON, NBO was demonstrated as a good liquid‐phase sintering additive for NASICON solid electrolyte. In the NASICON with 4.8 wt% NBO ceramic, most of the NASICON grains directly bonded with each other and some submicron sodium borates segregated in particulate form without full penetration to NASICON grain boundaries. This characteristic composite microstructure contributed to the high conductivity of the liquid‐phase sintered NASICON.     

Chemical‐Free Approach for Z‐Isomerization of Lycopene in Tomato Powder: Hot Air and Superheated Steam Heating above the Melting Point of Lycopene

Z‐isomers of lycopene exhibit higher bioavailability and antioxidant capacity than those of the all‐E‐isomer. Therefore, it is important to develop an efficient and environmentally friendly procedure for Z‐isomerization. The current methods for Z‐isomerization of (all‐E)‐lycopene use toxic chemicals such as organic solvents and catalysts. This study is aimed to develop a chemical‐free method for Z‐isomerization of (all‐E)‐lycopene in tomato powder by hot air and superheated steam heating. The Z‐isomerization reaction is promoted by heating above the melting point of lycopene. When heated with superheated steam, the thermal decomposition of lycopene is suppressed compared to that when heated with hot air. When tomato powder is heated at 240 °C for 5 min by superheated steam, the total Z‐isomer content and remaining lycopene are 69.0% and 90.7%, respectively, while with hot air heating, the total Z‐isomer content and remaining lycopene are 69.9% and 68.0%, respectively. These results indicate that the thermal Z‐isomerization of lycopene occurs in the molten state and heating in a low oxygen atmosphere suppresses the thermal decomposition of lycopene. Practical Applications: Tomato powder rich in lycopene Z‐isomers is an important ingredient for the food and animal feed industries. Since Z‐isomers of lycopene are more soluble in solvents including ethanol which is a low‐toxicity and environmentally friendly solvent, the efficiency of lycopene extraction with ethanol can be improved by using the Z‐isomer‐rich tomato powder as a raw material. The obtained Z‐isomer‐rich extract has a high added value because the Z‐isomers have higher bioavailability and antioxidant capacity than those of the all‐E‐isomer. In addition, since lycopene Z‐isomers exhibit higher accumulation efficiency and better color improvement in hen egg yolks than those of the all‐E‐isomer, Z‐isomer‐rich tomato powder is an effective animal feed.