Fast Detection and Classification of Microplastics below 10 µm Using CNN with Raman Spectroscopy.

In light of the growing awareness regarding the ubiquitous presence of microplastics (MPs) in our environment, recent efforts have been made to integrate Artificial Intelligence (AI) technology into MP detection. Among spectroscopic techniques, Raman spectroscopy is preferred for the detection of MP particles measuring less than 10 µm, as it overcomes the diffraction limitations encountered in Fourier transform infrared (FTIR). However, Raman spectroscopy's inherent limitation is its low scattering cross section, which often results in prolonged data collection times during practical sample measurements. In this study, we implemented a convolutional neural network (CNN) model alongside a tailored data interpolation strategy to expedite data collection for MP particles within the 1-10 µm range. Remarkably, we achieved the classification of plastic types for individual particles with a mere 0.4 s of exposure time, reaching an approximate confidence level of 85.47(±5.00)%. We postulate that the result significantly accelerates the aggregation of microplastic distribution data in diverse scenarios, contributing to the development of a comprehensive global microplastic map.

Direct Observation of Particle-To-Particle Variability in Ambient Aerosol pH Using a Novel Analytical Approach Based on Surface-Enhanced Raman Spectroscopy.

The pH of atmospheric aerosols is a key characteristic that profoundly influences their impacts on climate change, human health, and ecosystems. Despite widely performed aerosol pH research, determining the pH levels of individual atmospheric aerosol particles has been a challenge. This study presents a novel analytical technique that utilizes surface-enhanced Raman spectroscopy to assess the pH of individual ambient PM2.5-10 aerosol particles in conjunction with examining their hygroscopic behavior, morphology, and elemental compositions. The results revealed a substantial pH variation among simultaneously collected aerosol particles, ranging from 3.3 to 5.7. This variability is likely related to each particle's unique reaction and aging states. The extensive particle-to-particle pH variability suggests that atmospheric aerosols present at the same time and location can exhibit diverse reactivities, reaction pathways, phase equilibria, and phase separation properties. This pioneering study paves the way for in-depth investigations into particle-to-particle variability, size dependency, and detailed spatial and temporal variations of aerosol pH, thus deepening our understanding of atmospheric chemistry and its environmental implications.

Dark background-surface enhanced Raman spectroscopic detection of nanoplastics: Thermofluidic strategy.

This study aims to develop a cost-effective and time-efficient method for detecting nanoplastics, which have recently garnered significant attention due to their potential harmful impact on the water environment (XiaoZhi, 2021; Gigault et al., 2021; Mitrano et al., 2021; Ferreira et al., 2019). Although several techniques are available to accumulate data on microplastics, there is currently no universally accepted analytical technique for detecting nanoplastics (Gigault et al., 2021; Mitrano et al., 2021; Mitrano et al., 2019; Cai et al., 2021a; Allen et al., 2022). In this study, we have developed a substrate that exhibits Surface-enhanced Raman scattering (SERS) (Zhou et al., 2021; Lv et al., 2020; Lê et al., 2021; Hu et al., 2022; Chang et al., 2022; Yang et al., 2022; Xu et al., 2020; Jeon et al., 2021; Lee and Fang, 2022; Vélez-Escamilla and Contreras-Torres, 2022; Liu et al., 2022; Xie et al., 2023) activity over a large area and a dark background in optical (darkfield mode) vision, enabling the detection of sparkling nanoplastics on the substrate. This darkfield-based strategy allows for the point-by-point detection of single nanoplastics, offering cost and time-saving advantages over other resource-intensive analytical techniques. Our findings reveal the presence of PP nanoplastics in commonly used laboratory equipment, individual PE nanoplastics from a hot water-contained commercial paper cup, and the first detection of natural nanoplastics in coastal seawater. We believe that this technique will have a universal application in establishing a global map of nanoplastics and advancing our understanding of the environmental life cycle of plastics.

Novel Single-Particle Analytical Technique for Submicron Atmospheric Aerosols: Combined Use of Dark-Field Scattering and Surface-Enhanced Raman Spectroscopy.

Raman microspectrometry (RMS) is a useful single particle analysis method that can provide information on the mixing states, molecular species, and chemical functional groups of individual aerosol particles, which are difficult to determine by bulk analysis techniques. On the other hand, drawbacks, such as low Raman cross-section, spatial resolution (∼1 µm), and optical diffraction limit, make the analysis of atmospheric particles in the submicron size range difficult using conventional RMS. This study developed a new strategy to detect individual submicron-size atmospheric particles by combining dark-field (DF) microscopy and surface-enhanced Raman spectroscopy (SERS). The DF technique overcomes optical spatial diffraction limit by contrast enhancement, allowing the visualization of submicron particles. SERS facilitates spectroscopic characterization (obtaining information on molecular fingerprints and mixing states) of trace amounts of analyte by increasing the Raman scattering cross-section at the hot spot. SERS-active silver substrates sputter-coated on a Si wafer efficiently provided a clear background in the dark-field image and uniform hot spots over a large area, which were suitable for single-particle analysis. Various functional groups in individual particles and their heterogeneous mixing states were investigated, demonstrating the potential of this method to provide improved information on submicron atmospheric particles of femtogram-level masses. DF-SERS may elucidate the detailed physicochemical characteristics of individual submicron particles, providing new information on the formation mechanisms and fates of atmospheric particles.

Novel, acidic, and cold-adapted glycoside hydrolase family 8 endo-ß-1,4-glucanase from an Antarctic lichen-associated bacterium, Lichenicola cladoniae PAMC 26568.

Endo-ß-1,4-glucanase is a crucial glycoside hydrolase (GH) involved in the decomposition of cellulosic materials. In this study, to discover a novel cold-adapted ß-1,4-D-glucan-degrading enzyme, the gene coding for an extracellular endo-ß-1,4-glucanase (GluL) from Lichenicola cladoniae PAMC 26568, an Antarctic lichen (Cladonia borealis)-associated bacterium, was identified and recombinantly expressed in Escherichia coli BL21. The GluL gene (1044-bp) encoded a non-modular polypeptide consisting of a single catalytic GH8 domain, which shared the highest sequence identity of 55% with that of an uncharacterized protein from Gluconacetobacter takamatsuzukensis (WP_182950054). The recombinant endo-ß-1,4-glucanase (rGluL: 38.0 kDa) most efficiently degraded sodium carboxymethylcellulose (CMC) at pH 4.0 and 45°C, and showed approximately 23% of its maximum degradation activity even at 3°C. The biocatalytic activity of rGluL was noticeably enhanced by >1.3-fold in the presence of 1 mM Mn2+ or NaCl at concentrations between 0.1 and 0.5 M, whereas the enzyme was considerably downregulated by 1 mM Hg2+ and Fe2+ together with 5 mM N-bromosuccinimide and 0.5% sodium dodecyl sulfate. rGluL is a true endo-ß-1,4-glucanase, which could preferentially decompose D-cellooligosaccharides consisting of 3 to 6 D-glucose, CMC, and barley ß-glucan, without other additional glycoside hydrolase activities. The specific activity (15.1 U mg-1) and k cat/K m value (6.35 mg-1 s-1mL) of rGluL toward barley ß-glucan were approximately 1.8- and 2.2-fold higher, respectively, compared to its specific activity (8.3 U mg-1) and k cat/K m value (2.83 mg-1 s-1mL) toward CMC. The enzymatic hydrolysis of CMC, D-cellotetraose, and D-cellohexaose yielded primarily D-cellobiose, accompanied by D-glucose, D-cellotriose, and D-cellotetraose. However, the cleavage of D-cellopentaose by rGluL resulted in the production of only D-cellobiose and D-cellotriose. The findings of the present study imply that rGluL is a novel, acidic, and cold-adapted GH8 endo-ß-1,4-glucanase with high specific activity, which can be exploited as a promising candidate in low-temperature processes including textile and food processes.

Sorting Gold and Sand (Silica) Using Atomic Force Microscope-Based Dielectrophoresis.

Additive manufacturing-also known as 3D printing-has attracted much attention in recent years as a powerful method for the simple and versatile fabrication of complicated three-dimensional structures. However, the current technology still exhibits a limitation in realizing the selective deposition and sorting of various materials contained in the same reservoir, which can contribute significantly to additive printing or manufacturing by enabling simultaneous sorting and deposition of different substances through a single nozzle. Here, we propose a dielectrophoresis (DEP)-based material-selective deposition and sorting technique using a pipette-based quartz tuning fork (QTF)-atomic force microscope (AFM) platform DEPQA and demonstrate multi-material sorting through a single nozzle in ambient conditions. We used Au and silica nanoparticles for sorting and obtained 95% accuracy for spatial separation, which confirmed the surface-enhanced Raman spectroscopy (SERS). To validate the scheme, we also performed a simulation for the system and found qualitative agreement with the experimental results. The method that combines DEP, pipette-based AFM, and SERS may widely expand the unique capabilities of 3D printing and nano-micro patterning for multi-material patterning, materials sorting, and diverse advanced applications.

Novel Bi-Modular GH19 Chitinase with Broad pH Stability from a Fibrolytic Intestinal Symbiont of Eisenia fetida, Cellulosimicrobium funkei HY-13.

Endo-type chitinase is the principal enzyme involved in the breakdown of N-acetyl-d-glucosamine-based oligomeric and polymeric materials through hydrolysis. The gene (966-bp) encoding a novel endo-type chitinase (ChiJ), which is comprised of an N-terminal chitin-binding domain type 3 and a C-terminal catalytic glycoside hydrolase family 19 domain, was identified from a fibrolytic intestinal symbiont of the earthworm Eisenia fetida, Cellulosimicrobium funkei HY-13. The highest endochitinase activity of the recombinant enzyme (rChiJ: 30.0 kDa) toward colloidal shrimp shell chitin was found at pH 5.5 and 55 °C and was considerably stable in a wide pH range (3.5-11.0). The enzyme exhibited the highest biocatalytic activity (338.8 U/mg) toward ethylene glycol chitin, preferentially degrading chitin polymers in the following order: ethylene glycol chitin > colloidal shrimp shell chitin > colloidal crab shell chitin. The enzymatic hydrolysis of N-acetyl-ß-d-chitooligosaccharides with a degree of polymerization from two to six and colloidal shrimp shell chitin yielded primarily N,N'-diacetyl-ß-d-chitobiose together with a small amount of N-acetyl-d-glucosamine. The high chitin-degrading ability of inverting rChiJ with broad pH stability suggests that it can be exploited as a suitable biocatalyst for the preparation of N,N'-diacetyl-ß-d-chitobiose, which has been shown to alleviate metabolic dysfunction associated with type 2 diabetes.

Short-term storage of semen samples in acidic extender increases the proportion of females in pigs.

BACKGROUND: Sex preselection is a desired goal of the animal industry to improve production efficiency, depending on industry demand. In the porcine industry, there is a general preference for pork from female and surgically castrated male pigs. Therefore, the birth of more females than males in a litter leads to economic benefits and improved animal welfare in the pig production industry. Our previous study suggested that the porcine semen extender (BTS) adjusted to pH 6.2 maximises the differences in viability between X-chromosome-bearing (X) spermatozoa and Y-chromosome-bearing (Y) spermatozoa without affecting sperm's functional parameters. In this study we aimed to evaluate whether the pH 6.2 extender is applicable at the farm level for increasing the number of female piglets without a decline in spermatozoa fertility. Artificial insemination (AI) was carried out with spermatozoa stored at pH 6.2 and pH 7.2 (original BTS) at day 1 and day 2 of storage. Next, the functional parameters of the spermatozoa, litter size, farrowing rate, and female-to-male ratio of offspring were determined. RESULTS: Although sperm motility decreased significantly after 2 d of storage, the viability of spermatozoa was preserved at pH 6.2 for 3 d. There was no significant difference in the farrowing rate and average litter size between the group inseminated with the spermatozoa stored in (pH 7.2) and that inseminated with spermatozoa stored in acidic BTS. The percentage of female piglets was approximately 1.5-fold higher in sows inseminated on day 1 in the pH 6.2 than in the pH 7.2 group. Furthermore, although there was no significant difference in the female-to-male ratio, the percentage of female piglets born was slightly higher in the pH 6.2 group than in the pH 7.2 group on day 2. CONCLUSIONS: The method optimised in our study is simple, economical, and may enhance the number of female births without any decline in spermatozoa fertility.

Novel Anti-Fungal d-Laminaripentaose-Releasing Endo-ß-1,3-glucanase with a RICIN-like Domain from Cellulosimicrobium funkei HY-13.

Endo-ß-1,3-glucanase plays an essential role in the deconstruction of ß-1,3-d-glucan polysaccharides through hydrolysis. The gene (1650-bp) encoding a novel, bi-modular glycoside hydrolase family 64 (GH64) endo-ß-1,3-glucanase (GluY) with a ricin-type ß-trefoil lectin domain (RICIN)-like domain from Cellulosimicrobium funkei HY-13 was identified and biocatalytically characterized. The recombinant enzyme (rGluY: 57.5 kDa) displayed the highest degradation activity for laminarin at pH 4.5 and 40 °C, while the polysaccharide was maximally decomposed by its C-terminal truncated mutant enzyme (rGluYΔRICIN: 42.0 kDa) at pH 5.5 and 45 °C. The specific activity (26.0 U/mg) of rGluY for laminarin was 2.6-fold higher than that (9.8 U/mg) of rGluYΔRICIN for the same polysaccharide. Moreover, deleting the C-terminal RICIN domain in the intact enzyme caused a significant decrease (>60%) of its ability to degrade ß-1,3-d-glucans such as pachyman and curdlan. Biocatalytic degradation of ß-1,3-d-glucans by inverting rGluY yielded predominantly d-laminaripentaose. rGluY exhibited stronger growth inhibition against Candida albicans in a dose-dependent manner than rGluYΔRICIN. The degree of growth inhibition of C. albicans by rGluY (approximately 1.8 µM) was approximately 80% of the fungal growth. The superior anti-fungal activity of rGluY suggests that it can potentially be exploited as a supplementary agent in the food and pharmaceutical industries.

Combination Treatment of Arazyme and Soy Leaf Extract Attenuates Hyperglycemia and Hepatic Steatosis in High-Fat Diet-Fed C57BL/6J Mice.

Arazyme and extracts of soy leaves (ESLs) are used as ingredients for functional foods; however, their combined administration has not been studied. This study assessed the combined effect of Arazyme and ESLs in high-fat-diet (HFD)-induced obese C57BL/6J mice fed 2 mg/kg Arazyme, 50 mg/kg ESLs, or a combination of 2 mg/kg Arazyme and 50 mg/kg ESLs by oral gavage for 13 weeks. Individually, Arazyme and ESLs had no effect on the HFD-induced phenotypes. The combination of Arazyme and ESLs significantly suppressed body weight gain, improved glucose and insulin tolerance, and suppressed hepatic steatosis by reducing lipid synthesis and enhancing lipid utilization gene expression. Furthermore, the combination significantly reduced HFD-induced plasma bile acid reabsorption by suppressing bile acid transporter expression, including the ATP biding cassette subfamily B member 11 (Abcb11), solute carrier family 10 member 1 (Slc10a1), Slc10a2, Slc51a, and Slc51b in the liver and gut. Moreover, the combination of Arazyme and ESLs significantly prevented HFD-induced islet compensation in the pancreas. These results suggest that the incorporation of Arazyme combined with ESLs reduces HFD-induced body weight, hyperglycemia, and hepatic steatosis by regulating liver-gut bile acid circulation in HFD-fed mice. This combination can markedly reduce treatment doses and enhance their therapeutic effects, thereby reducing therapeutic healthcare costs.

Development of a novel denture care agent with highly active enzyme, arazyme.

BACKGROUND: The importance of efficient denture deposit removal and oral hygiene has been further underscored by the continuous increase of denture wearers. Denture hygiene management has also become an important aspect associated with denture-induced stomatitis. This study aims to evaluate the denture cleaning effect of arazyme, the metalloprotease produced from the Serratia proteamaculans HY-3. We performed growth inhibition tests against oral opportunistic pathogens to be used as a potential oral health care agent. METHODS: The proteolytic activities of arazyme was evaluated over broad ranges of temperature, pH, and denture components compared to those of subtilisin in commercially available denture cleansers. The washing effects of arazyme were also measured by using homogeneously soiled EMPA 105 cottons. To investigate the denture cleaning capability of arazyme, artificially contaminated dentures were treated with arazyme, subtilisin (Everlase 6.0T), and Polident®, respectively. The growth kinetics of Candida albicans, Enterococcus faecalis, Staphylococcus epidermis, and Streptococcus mutans were evaluated in the presence of different concentrations of arazyme to estimate the prevention effects of arazyme against major oral opportunistic pathogens. RESULTS: Arazyme showed strong proteolytic activities over wide temperature and pH ranges compared with the serine protease of the subtilisin family. Arazyme demonstrated efficient removal and decomposition of artificially contaminated dentures and showed explicit washing effects against soiled cottons. Moreover arazyme inhibited the growth of oral opportunistic pathogens, including C. albicans, E. faecalis, S. epidermis, and S. mutans, with more than 80% inhibition against C. albicans, the major cause of denture stomatitis, with 250 mg/mL arazyme. CONCLUSIONS: Arazyme shows promise as a biological oral health care agent with effective cleaning and antimicrobial activities and is a potential source for developing novel denture care agents.

Spectroscopic evidence on the acetonitrile cleavage at mild condition.

Among the present numerous chemical libraries, acetonitrile is the one of famous common organic solvents widely used in modern science and industry. Since it has been known as very stable and inert solvent, there has been little doubt on its catalytic decomposition to cyanide in mild condition. In this report, I provide new evidence on the catalytic decomposition of acetonitrile at conventional gold surfaces without any electrochemical treatment. Various surface enhanced Raman spectroscopic (SERS) measurements on high-purity acetonitrile reveal that the observed anomalous peak originates from the plasmonically cleaved cyanide group on SERS-active gold surface, which is also supported by the results of time of flight-secondary ion mass spectrometry (TOF-SIMS). This work sheds light on the plasmonic induced unprecedented reaction of the small chemical species that have been known intact.

Identification and Characterization of a Novel, Cold-Adapted d-Xylobiose- and d-Xylose-Releasing Endo-ß-1,4-xylanase from an Antarctic Soil Bacterium, Duganella sp. PAMC 27433.

Endo-ß-1,4-xylanase is a key enzyme in the degradation of ß-1,4-d-xylan polysaccharides through hydrolysis. A glycoside hydrolase family 10 (GH10) endo-ß-1,4-xylanase (XylR) from Duganella sp. PAMC 27433, an Antarctic soil bacterium, was identified and functionally characterized. The XylR gene (1122-bp) encoded an acidic protein containing a single catalytic GH10 domain that was 86% identical to that of an uncultured bacterium BLR13 endo-ß-1,4-xylanase (ACN58881). The recombinant enzyme (rXylR: 42.0 kDa) showed the highest beechwood xylan-degrading activity at pH 5.5 and 40 °C, and displayed 12% of its maximum activity even at 4 °C. rXylR was not only almost completely inhibited by 5 mM N-bromosuccinimide or metal ions (each 1 mM) including Hg2+, Ca2+, or Cu2+ but also significantly suppressed by 1 mM Ni2+, Zn2+, or Fe2+. However, its enzyme activity was upregulated (>1.4-fold) in the presence of 0.5% Triton X-100 or Tween 80. The specific activities of rXylR toward beechwood xylan, birchwood xylan, oat spelts xylan, and p-nitrophenyl-ß-d-cellobioside were 274.7, 103.2, 35.6, and 365.1 U/mg, respectively. Enzymatic hydrolysis of birchwood xylan and d-xylooligosaccharides yielded d-xylose and d-xylobiose as the end products. The results of the present study suggest that rXylR is a novel cold-adapted d-xylobiose- and d-xylose-releasing endo-ß-1,4-xylanase.

Direct measurement of curvature-dependent surface tension of an alcohol nanomeniscus.

Surface tension is a key parameter for understanding nucleation in the very initial stage of phase transformation. Although surface tension has been predicted to vary with the curvature of the liquid-vapor interface, particularly at the large curvature of, e.g., the subnanometric critical nucleus, experimental study still remains challenging due to inaccessibility to such a small cluster. Here, by directly measuring the critical size of a single capillary-condensed nanomeniscus using atomic force microscopy, we address the curvature dependence of surface tension of alcohols and observe that the surface tension is doubled for ethanol and n-propanol with a radius-of-curvature of ∼-0.46 nm. We also find that the interface of larger negative (positive) curvature exhibits larger (smaller) surface tension, which evidently governs nucleation at the ∼1 nm scale and below, indicating more facilitated nucleation than normally expected. Such well characterized curvature effects contribute to better understanding and accurate analysis of nucleation occurring in various fields including materials science and atmospheric science.

Gold nanoparticle-mediated non-covalent functionalization of graphene for field-effect transistors.

Since its discovery, graphene has attracted much attention due to its unique electrical transport properties that can be applied to high-performance field-effect transistors (FETs). However, mounting chemical functionalities onto graphene inevitably involves the breaking of sp2 bonds, resulting in the degradation of the mechanical and electrical properties compared to pristine graphene. Here, we report a new strategy to chemically functionalize graphene for use in FETs without affecting the electrical performance. The key idea is to control the Fermi level of the graphene using the consecutive treatment of gold nanoparticles (AuNPs) and thiol-SAM (self-assembled monolayer) molecules, inducing positive and negative doping effects, respectively, by flipping the electric dipoles between AuNPs and SAMs. Based on this method, we demonstrate a Dirac voltage switcher on a graphene FET using heavy metal ions on functionalized graphene, where the carboxyl functional groups of the mediating SAMs efficiently form complexes with the metal ions and, as a result, the Dirac voltage can be positively shifted by different charge doping on graphene. We believe that the nanoparticle-mediated SAM functionalization of graphene can pave the way to developing high-performance chemical, environmental, and biological sensors that fully utilize the pristine properties of graphene.

Exploring the Hydration Water Character on Atomically Dislocated Surfaces by Surface Enhanced Raman Spectroscopy.

Hydration is ubiquitous in any kind of water-substance interaction such as in various interfacial and biological processes. Despite substantial progress made to date, however, still less explored is the hydration behavior on complex heterogeneous surfaces, such as the water surrounding the protein, which requires a platform that enables systematic investigation at the atomic scale. Here, we realized a heterogeneous self-assembled monolayer system that allows both controllable mixing with hydrophobic or hydrophilic groups and precise distance control of the functional carboxyl groups from the surface by methylene spacer groups. Using surface-enhanced Raman spectroscopy (SERS), we first demonstrated the hydrophobic (or hydrophilic) mixing ratio-dependent pK a variation of the carboxyl group. Interestingly, we observed a counterintuitive, non-monotonic behavior that a fractionally mixed hydrophobic group can induce significant enhancement of dielectric strength of the interfacial water. In particular, such a fractional mixing substantially decreases the amide coupling efficiency at the surface, as manifested by the corresponding pK a decrease. The SERS-based platform we demonstrated can be widely applied for atomically precise control and molecular-level characterization of hydration water on various heterogeneous surfaces of biological and industrial importance.

Sub-nanoscale probing of nanojunction using heterogeneous gap-mode Raman spectroscopy.

Symmetric bifunctional molecule-linked nanogap structures have been frequently used in nanoelectronics, it is still challenging to discriminate the phenomenon that happened at both interfacial regions with subnanoscale resolution. Here, we fabricated platinum-silver or silver-platinum heterogeneous nanogap structures using a symmetric isocyanide terminated molecule, and using surface-enhanced Raman spectroscopy, we investigated the electrochemical potential-dependent change in the two distinguishable isocyanide stretching bands in such structures. Counterintuitively, we observed that the isocyanide group at the nanoparticle surface experiences more enhanced effective potential than the one at the plate surface, and this is attributed to the nanoparticle-induced effects rather than the potential drop that conventionally occurred due to molecular resistance. Our study provides a novel strategy allowing the subnanoscale investigation of numerous interfacial phenomena, which could not be achieved via conventional spectroscopic techniques.

Arazyme Suppresses Hepatic Steatosis and Steatohepatitis in Diet-Induced Non-Alcoholic Fatty Liver Disease-Like Mouse Model.

Arazyme, a metalloprotease from the spider Nephila clavata, exerts hepatoprotective activity in CCL4-induced acute hepatic injury. This study investigated the hepatoprotective effects in high-fat diet (HFD)-induced non-alcoholic fatty liver disease-like C57BL/6J mice. The mice were randomly divided into four groups (n = 10/group): the normal diet group, the HFD group, the arazyme group (HFD with 0.025% arazyme), and the milk thistle (MT) group (HFD with 0.1% MT). Dietary supplementation of arazyme for 13 weeks significantly lowered plasma triglyceride (TG) and non-esterified fatty acid levels. Suppression of HFD-induced hepatic steatosis in the arazyme group was caused by the reduced hepatic TG and total cholesterol (TC) contents. Arazyme supplementation decreased hepatic lipogenesis-related gene expression, sterol regulatory element-binding transcription protein 1 (Srebf1), fatty acid synthase (Fas), acetyl-CoA carboxylase 1 (Acc1), stearoyl-CoA desaturase-1 (Scd1), Scd2, glycerol-3-phosphate acyltransferase (Gpam), diacylglycerol O-acyltransferase 1 (Dgat1), and Dgat2. Arazyme directly reduced palmitic acid (PA)-induced TG accumulation in HepG2 cells. Arazyme suppressed macrophage infiltration and tumor necrosis factor α (Tnfa), interleukin-1ß (Il1b), and chemokine-ligand-2 (Ccl2) expression in the liver, and inhibited secretion of TNFα and expression of inflammatory mediators, Tnfa, Il1b, Ccl2, Ccl3, Ccl4, and Ccl5, in PA-induced RAW264.7 cells. Arazyme effectively protected hepatic steatosis and steatohepatitis by inhibiting SREBP-1-mediated lipid accumulation and macrophage-mediated inflammation.

Ice-VII-like molecular structure of ambient water nanomeniscus.

Structural transformations originating from diverse rearrangements of the hydrogen bonding in water create various phases. Although most phases have been well investigated down to the molecular level, the molecular structure of the nanomeniscus, a ubiquitous form of nanoscale water in nature, still remains unexplored. Here, we demonstrate that the water nanomeniscus exhibits the stable, ice-VII-like molecular structure in ambient condition. Surface-enhanced Raman spectroscopy on trace amounts of water, confined in inter-nanoparticle gaps, shows a narrowed tetrahedral peak at 3340 cm-1 in the OH-stretching band as well as a lattice-vibrational mode at 230 cm-1. In particular, the ice-VII-like characteristics are evidenced by the spectral independence with respect to temperature variations and differing surface types including the material, size and shape of nanoparticles. Our results provide un unambiguous identification of the molecular structure of nanoconfined water, which is useful for understanding the molecular aspects of water in various nanoscale, including biological, environments.

Heterogeneous gap-mode nanostructure for surface-enhanced Raman spectroscopic evaluation of charge transfer between noble metal nanoparticles and formaldehyde vapor.

Gap-mode nanostructures offer a reliable, scalable and controllable Raman substrate with high signal enhancement, and they are widely used in surface-enhanced Raman spectroscopy. Heterogeneous gap-mode structures composed of different types of nanoparticles with the underlying substrate have been studied only in terms of understanding the electromagnetic field enhancement mechanism up to now, just by focusing on the role of hot spot as enhancing the Raman signal itself. In this study, gold and platinum nanoparticle-based heterogeneous gap-mode structures were fabricated on gold surface, and used to evaluate minute changes in the surface charged state (surface potential) of the nanoparticle interacting with different organic vapors. By monitoring the surface-enhanced Raman signal change of isonitrile probes in the hot spot, it was revealed that gold and platinum nanoparticles show opposite directions of charge transfer over the same formaldehyde treatment. This strategy offers a new way to evaluate the charge transfer phenomenon between organic vapor and nanoparticles, which is especially important in catalytic application, using conventional surface-enhanced Raman spectroscopy.