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Clostridium fermentations have been developed for producing butanol and other value-added chemicals, but their development is constrained by some limitations, such as relatively high substrate cost and the need to maintain an anaerobic condition. Recently, co-culture is emerging as a popular way to address these limitations by introducing a partner strain with Clostridium. Generally speaking, the co-culture strategy enables the use of a cheaper substrate, maintains the growth of Clostridium without any anaerobic treatment, improves product yields, and/or widens the product spectrum. Herein, we review recent developments of co-culture strategies involving Clostridium species according to their partner stains' functions with representative examples. We also discuss research challenges that need to be addressed for the future development of Clostridium co-cultures. Clostridium co-culture has emerged as a solution to some problems faced by Clostridium monoculture. Co-culturing Clostridium with cellulolytic strains or acetogens enables the production of butanol from cheaper substrates such as lignocellulosic biomass and syngas. Aerotolerance is possible in anaerobic Clostridium fermentation in co-cultures with oxygen-consuming microbes. Co-culturing solventogenic Clostridium with acetogens can improve the production of butanol and its derivatives by increasing carbon recovery and relieving solvent toxicity. Other products, such as H 2 or fatty acids, can be efficiently produced by the co-culture of Clostridium and other H 2 -producing strains (such as PNS bacteria), or chain-elongating strains respectively. [ABSTRACT FROM AUTHOR]

Antimony is highly toxic and a key water pollutant, which needs to be monitored closely. To date, however, most analytical methods for antimony detection are quite limited because they are complicated, expensive, and not suitable for real-time monitoring of antimony. In this study, a label-free and rapid method for antimony ions (Sb3+) detection is developed based on liquid crystals and a 10-mer poly-adenine oligonucleotide as a specific recognition probe for the first time. The working principle is based on the binding of the oligonucleotide to Sb3+, which weakens the interaction between the oligonucleotide and cationic surfactants. As a result, the event induces a planar-to-homeotropic orientational change of liquid crystals and a bright-to-dark optical change under crossed polars. This liquid crystal-based optical sensor exhibits a rapid response to Sb3+ in 10 s, a detection range between 20 nM and 5 μM, and a detection limit at 6.7 nM calculated from 10-mins assay time. It also shows good selectivity against other metal ions including Ag+, Cd2+, Cu2+, Fe3+, K+, Mg2+, Mn2+, Na+, Pb2+, and Zn2+. Moreover, this system can be used to detect Sb3+ in aqueous solutions with different pH or ionic strengths. This simple, fast, and low-cost liquid crystal-based sensing approach with high sensitivity and selectivity has a high potential for detecting Sb3+ in natural environments and industrial wastewater. [Display omitted] • A liquid crystal sensor by using a probe Poly-A oligonucleotide for Sb3+ detection • The addition of Sb3+ weakens the interaction between Poly-A and surfactants • The sensor has a low detection limit at 6.7 nM and response time at 10 s • The system shows good selectivity and detection ability in different environments [ABSTRACT FROM AUTHOR]

We report a heterogeneous reaction to reduce HAuCl4 solution and form gold nanoparticles (AuNPs) on stainless steel needle surfaces. Through bubbling of nitrogen, AuNPs dispersed into the solution homogeneously. Subsequently, AuNPs were immobilized on the surface of polydimethylsiloxane (PDMS). The immobilized AuNPs exhibit catalase-mimetic activity in a 2 wt% H2O2 solution. [ABSTRACT FROM AUTHOR]

The formation of the electrical double layer (EDL) in an aqueous solution in contact with the charged solid surfaces of a slit-type nanopore has been simulated by grand canonical Monte Carlo (GCMC) and canonical Monte Carlo (CMC) methods. In the GCMC simulations, a primitive EDL model in which water is considered as a continuum and the ions are considered as hard spheres is used. The results are found to be slightly different from those predicted by the Gouy-Chapman model at low electrolyte concentration and low surface charge density. The GCMC results were then used as an initial condition for the CMC sinmulations of a nonprimitive model in which the EDL is composed of molecular water (four-point transferable intermolecular potential, together with fluctuating charge model), cations (Na[SUP+]), and anions (Cl[SUP-]). The nonprimitive model provides a very different view of the EDL at the atomic level. For example, a single layer of water molecules, instead of counterions, is strongly adsorbed on negatively charged surfaces. This feature cannot be observed in the Gouy-Chapman or in the primitive model. Moreover, because the charged surfaces are covered by water molecules, the maximum counterion concentration in a nanopore occurs at the center, instead of on the surfaces, of the pore. This phenomenon is also supported by experimental data and theoretical calculations found in the literature. [ABSTRACT FROM AUTHOR]

Monte Carlo simulations have been performed to study the arrangement of water molecules between charged surfaces. The molecular water used—the four- point transferable intermolecular potential (TIP4P), together with fluctuating charge (FQ)—constitutes the water model TIP4P-FQ. The TIP4P-FQ features the same molecular frame as the TIP4P model; however, with the former, charges on the molecular sites of the same molecule are allowed to fluctuate in response to their environment. Therefore, the induced dipole moment under an external field is inherently considered in the TIP4P-FQ water model. This feature makes it more useful than multipoint fixed-charge models, such as the TIP4P, in studying water arrangement between charged surfaces. The formation of a few ordering layers of water molecules adjacent to a charged surface is confirmed by (N,V,T) Monte Carlo simulations. The preferable orientation of water molecules in this study is found to be similar to previous findings in the literature, with the oxygen atoms pointing to the positively charged surface (oxygen-down) and the hydrogen atoms pointing to the negatively charged surface (oxygen-up). Modeling results also demonstrate that the dominant orientation at the negatively charged surface is one O-H bond pointing to the surface while another O-H bond is aligned parallel to the charged surface. In addition, simulation results using the TIP4P-FQ water model show that the water density in the interfacial region increases ∼8%-14%, which is lower than the density increase observed in experimental data discussed in the literature. [ABSTRACT FROM AUTHOR]

Abnormal protease activities are associated with cancers, vascular diseases and Alzheimer diseases. Therefore, detection of protease activities has become increasingly important in recent years. Herein, we report a semi-quantitative, liquid crystal (LC)-based protease assay for naked-eye detection of protease activity. In this assay, casein molecules are cleaved by proteases into small peptide fragments, which can be quantified either by using Lowry’s method or using LC. In the latter, peptide fragments adsorb on a solid surface and disrupt LC to produce a bright spot for naked-eye detection. The bright spot is observed only when the surface-adsorbed peptide density exceeds a critical value. In the assay, a major challenge is how to separate undigested casein and remaining protease from peptide fragments to prevent their interferences with LC. To overcome this issue, trichloroacetic acid (TCA) is added to precipitate casein and proteases. By using the assay, we are able to detect 10 ng/mL of protease (activity 7.23 U/mg protease, R 2  = 0.991) or 6.5 μg/mL of peptide fragments. Finally, a continuous protease assay is developed to minimize manual sampling and reduce errors in kinetic studies. [ABSTRACT FROM AUTHOR]

Clostridium beijerinckii G117 produces hydrogen (∼4400 mL/L) from 15 g/L of native crude glycerol (CG). While increasing the native-CG to 20–80 g/L, strain G117 rejects 34–90% of CG and fails to support a relative enhancement in hydrogen production. Subsequently, to enhance the native-CG assimilation, and hydrogen production from strain G117, various agro-residual hydrolysates (ARH), and several metal-ions have individually tested as media-supplements. Among tested, rice bran hydrolysate (RBH) and ferrous chloride (Fe2+) are selected as media-supplements. By employing RSM-based central composite design, the medium composed of 37.63 g/L CG, 3.65 g/L RBH and 1.11 mM Fe2+ is optimized which results a favorable initial redox potential (−191.0 ± 1.5 mV), higher cellular growth (6.73 ± 0.12 OD 600), and 17350 ± 170 mL/L of hydrogen production from strain G117. The analysis of total-mass and electron balances suggest that this bioprocess is remarkably efficient (82–99%), and records the highest yield of hydrogen (2.27 ± 0.02 mol/mol glycerol) ever reported in literature. [Display omitted] • Clostridium beijerinckii G117 produces hydrogen from <15 g/L of crude glycerol (CG). • While raising CG to 20–80 g/L in the media, strain G117 rejects 34–90% of CG supplied. • Adding agro-residual hydrolysates/metal-ions alter CG-utilization and hydrogen yield. • Media of CG with rice bran hydrolysate as co-substrate and Fe2+ is optimized (OpM). • OpM supports G117 to produce 17350 mL/L hydrogen with yield of 2.27 mol H2 /mol Glycerol. [ABSTRACT FROM AUTHOR]

Proteases play a pivotal role in regulating important physiological processes from food digestion to blood clotting. They are also important biomarkers for many diseases such as cancers. The importance of proteases has led to extensive efforts in the screening of proteases and their inhibitors as potential drug molecules. For example, human immunodeficiency virus (HIV) patients have been treated with HIV-1 protease inhibitors to prolong the life expectancy of patients. Such a close relationship between diseases and proteases provides a strong motivation for developing sensitive, selective, and robust protease assays and sensors, which can be exploited to discover new proteases and inhibitors. In this aspect, protease assays based on levels of proteolytic activities are more relevant than protease affinity assays such as immunoassays. In this review, recent developments of protease activity assays based on different detection principles are discussed and compared. For homogenous assays, fluorescence-based techniques are the most popular due to their high sensitivity and quantitative results. However, homogeneous assays have limited multiplex sensing capabilities. In contrast, heterogeneous assays can be employed to detect multiple proteases simultaneously, given the microarray technology that is already available. Among them, electrochemical methods, surface spectroscopy techniques, and enzyme-linked peptide protease assays are commonly used. Finally, recent developments in liquid crystal (LC)-based protease assays and their applications for detecting proteases and their inhibitors are discussed. [ABSTRACT FROM AUTHOR]

Cascade reactions involved unstable intermediates are often encountered in biological systems. In this study, we developed combined cross-linked enzyme aggregates (combi-CLEA) to catalyze a cascade reaction which involves unstable hydrogen peroxide as an intermediate. The combi-CLEA contains two enzymes̶ glucose oxidase (GOx) and horseradish peroxidase (HRP) which are cross-linked together as solid aggregates. The first enzyme GOx catalyzes the oxidation of glucose and produces hydrogen peroxide, which is used by the second enzyme HRP to oxidize 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The apparent reaction rate of the cascade reaction reaches 10.5 ± 0.5 μM/min when the enzyme ratio is 150:1 (GOx:HRP). Interestingly, even in the presence of catalase, an enzyme that quickly decomposes hydrogen peroxide, the reaction rate only decreases by 18.7% to 8.3 ± 0.3 μM/min. This result suggests that the intermediate hydrogen peroxide is not decomposed by catalase due to a short diffusion distance between GOx and HRP in the combi-CLEA. Scanning electron microscopy images suggest that combi-CLEA particles are hollow spheres and have an average diameter around 250 nm. Because of their size, combi-CLEA particles can be entrapped inside a nylon membrane for detecting glucose by using the cascade reaction. [ABSTRACT FROM AUTHOR]

Current anti-fibrotic effect of antioxidants in vivo is disappointing due probably to the fact that once liver fibrogenesis is established it is too advanced to be reversed by anti-oxidation mechanism. We consider antioxidant may only act on the early phase of fibrogenesis. Thus, we had previously established an early liver fibrosis animal model using an inducible expression vector (pPK9a), which contains TGF-β gene and was hydro-dynamically transferred into mice to induce a transient liver fibrosis. TGF-β1 has been well documented to up-regulate the expression of α2(1) collagen (Col 1A2) gene in the liver via the reactive oxygen species (ROS); the process triggers inflammation, leading to hepatic stellate cells (HSC) activation and liver fibrogenesis. Using our animal model and ROS, cyclooxygenase-2 (Cox-2) and Col 1A2 promoter assays as screening targets, we report here that a maleic acid derivative isolated from the Antrodia camphorata mycelium strongly decreases ROS production, promoter activity of Cox-2 and Col 1A2, intracellular calcium, expression of alpha-smooth muscle actin (α-SMA), Smad4-p-Smad2/3 co-localization in cell nucleus and the DNA binding activity of Sp1. Our results suggest that the maleic acid derivative prevents liver fibrosis at an early phase both in vitro and in vivo through the inhibition of ROS, inflammation and the activation of HSC. [ABSTRACT FROM AUTHOR]

Butanol and butyric acid produced from acetone-butanol-ethanol (ABE) fermentation can be used to produce butyl butyrate, an important fragrance ester. However, low levels of butanol and butyric acid need to be purified from culture media first with energy-intensive distillation processes. In this study, a triphasic (organic/aqueous/fluorous) system is developed to esterify butanol and butyric acid in spent culture media into butyl butyrate directly without purification. The produced butyl butyrate forms a distinct organic phase floating on top and can then be separated easily. In a model system containing 37.1 g/L of butanol and 44.1 g/L of butyric acid, 57% of the butanol is converted to butyl butyrate after 8 h of esterification. With multiple cycles of esterification and product removal, butanol conversion can be further increased to 86%. When spent culture medium containing 7.12 g/L of butanol and 4.81 g/L of butyric acid is used for esterification, 38% of butanol (0.36 mmol) is consumed and 0.33 mmol of butyl butyrate is produced. However, when ABE fermentation and esterification are carried out simultaneously, only 0.042 mmol of butyl butyrate is produced, probably due to the incompatible pH requirements for cell growth (pH 5–7) and esterification (pH 2–3). [ABSTRACT FROM AUTHOR]

Polyethylene glycol (PEG) hydrogel is permeable to biomolecules, but its permeability depends on the molecular weight of monomers and the concentration of monomer solutions. In this study, we show that PEG hydrogel made from 20% to 30% of PEG700 monomer is permeable to amino acids yet impermeable to oligopeptides. Because of its unique permeability, the gel can be used to detect protease by separating amino acids from oligopeptides when proteases cleave the oligopeptides and release amino acids. Based on this principle, an UV crosslinked gel array is fabricated on a chip for simultaneous detection of protease in up to 40 samples with only 1 µl of volume required for each sample. As a proof of concept, the on-chip protease assays are used to detect trypsin in buffer and serum. The detection limits are 1.2 nM in buffer and 17.7 nM in serum, which are comparable to conventional protease assays. Moreover, because only 1 µl of liquid is required, as little as 1.2 fmol of trypsin can be detected by using the on-chip assay. The protease assay also shows good specificity for trypsin and chymotrypsin. The gel array chip could be a useful miniaturized platform for high-throughput detection of different proteases and screening of their inhibitors. [ABSTRACT FROM AUTHOR]

There is a constant need to identify novel inhibitors to combat β-lactamase-mediated antibiotic resistance. In this study, we identify three penicillinase-binding peptides, P1 (DHIHRSYRGEFD), P2 (NIYTTPWGSNWS), and P3 (SHSLPASADLRR), using a phage display library. Surface plasmon resonance (SPR) is utilized for quantitative determination and comparison of the binding specificity of selected peptides to penicillinase. An SPR biosensor functionalized with P3-GGGC (SHSLPASADLRRGGGC) is developed for detection of penicillinase with excellent sensitivity (15.8 RU nM −1 ) and binding affinity ( K D = 0.56 nM). To determine if peptides can be good inhibitors for penicillinase, these peptides are mixed with penicillinase and their inhibition efficiency is determined by measuring the hydrolysis of substrate penicillin G using UV–vis spectrophotometry. Peptide P2 (NIYTTPWGSNWS) is found to be a promising penicillinase inhibitor with a K i of 9.22 μM and a K i ′ of 33.12 μM, suggesting that the inhibition mechanism is a mixed pattern. This peptide inhibitor (P2) can be used as a lead compound to identify more potent small molecule inhibitors for penicillinase. This study offers a potential approach to both detection of β-lactamases and development of novel inhibitors of β-lactamases. [ABSTRACT FROM AUTHOR]

Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp. [ABSTRACT FROM AUTHOR]

Recent advance in liquid crystal (LqC) based immunoassays enables label-free detection of antibody, but manual preparation of LqC cells and injection of LqC are required. In this work, we developed a new format of LqC-based immunoassay which is hosted in a microfluidic device. In this format, the orientations of LqC are strongly influenced by four channel walls surrounding the LqC. When the aspect ratio (depth/width) of the channel is smaller than 0.38, LqC orients homeotropically inside the microchannel and appears dark. After antigens bind to immobilized antibodies on the channel walls, a shift of the LqC appearance from dark to bright (due to the disruption of LqC orientation) can be visualized directly. To streamline the immunoassay process, a tubing cartridge loaded with a sample solution, washing buffers and a plug of LqC is connected to the microfluidic device. By using pressure-driven flow, the cartridge allows antigen/antibody binding, washing and optical detection to be accomplished in a sequential order. We demonstrate that this microfluidic immunoassay is able to detect anti-rabbit IgG with a naked-eye detection limit down to 1 μg mL −1 . This new format of immunoassay provides a simple and robust approach to perform LqC-based label-free immunodetection in microfluidic devices. [ABSTRACT FROM AUTHOR]

A protease assay is reported by using enzymatic deposition of silver particles to report protease activity as optical readouts. In this assay, a biotinylated oligopeptide, which is a protease substrate, is first immobilized on a glass surface. In the absence of trypsin, streptavidin−alkaline phosphatase (SA−ALP) complex can bind to biotin and catalyze enzymatic silver deposition (ESD), which leads to a layer of highly reflective silver particles deposited on the surface. In the presence of trypsin, the immobilized oligopeptide is cleaved and biotin is removed. As a result, SA−ALP does not bind to the surface, and ESD does not happen. The limit of detection (LOD) of this assay is closely related to the surface density of oligopeptide substrate. When the surface density of oligopeptide is 0.12 molecule nm−2, the LOD for trypsin can reach 10 ng mL−1 (400 × 10−12 m). It is also demonstrated that this ESD-based protease assay can be applied to screening of protease inhibitors, such as benzamidine hydrochloride. [ABSTRACT FROM AUTHOR]

We reported an oligopeptide immobilization strategy for improving stability and sensitivity of liquid-crystal (LC) based protease assay. In this strategy, oligopeptides are immobilized by using N -terminal cysteine or free amine groups on lysine residues to react with surface aldehyde groups and form multiple anchoring points. Our results show that the number of anchoring points is an important factor for improving stability of the immobilized oligopeptides. Oligopeptides with multiple anchoring points are very stable on the surface. They can only be cleaved from the surface by using proteases such as trypsin or α-chymotrypsin. This phenomenon provides a principle for developing an assay for the detection of proteases. On the other hand, oligopeptides with a single anchoring point cannot form stable linkage on the surface, and they can be easily washed off during rinsing steps. By immobilizing oligopeptides with different surface densities, concentrations of trypsin and α-chymotrypsin can be estimated simply by counting the number of bright LC spots. The higher the concentrations of trypsin and α-chymotrypsin, the less LC spots can be observed. In addition, the limit of detection (LOD) of the assay can be lowered by allowing a very large oligopeptide fragment to desorb from the surface after the cleavage. This task can be accomplished by immobilizing an oligopeptide with all anchoring points located at both ends while the cleavage sites are located near the anchoring points. Based on the principle, optimized LODs for trypsin and α-chymotrypsin can reach 1 and 0.1 ng/mL, respectively. [ABSTRACT FROM AUTHOR]

Highlights: [•] Millifluidic reactor can be used to prepare cross-linked cellulase aggregate (XCA). [•] The XCA has a very uniform size distribution between 200nm and 400nm. [•] Flow rates and mixing patterns can be precisely controlled. [•] It is possible to control the particle size of the XCA. [•] It shows excellent thermal stability, and can be reused for several cycles. [Copyright &y& Elsevier]

Highlights: [•] Hybrid cellulase aggregate consists of cross-linked cellulase layers physically adsorbed on silica gel. [•] Higher glucose production than cross-linked cellulase aggregates without silica core. [•] Reusable for cellulose and biomass hydrolysis. [Copyright &y& Elsevier]

Abstract: We report a biosensor for detecting organophosphates (OPs) by using liquid crystal (LC). The mechanism of the biosensor is based on detection of minute pH changes during the enzymatic hydrolysis of OPs. To hydrolyze OPs, paraoxonase 1 (PON1) is immobilized on a copper grid which also hosts pH-sensitive LC, 4-cyano-4′-pentylbiphenyl (5CB) doped with 0.3% of 4′-pentyl-biphenyl-4-carboxylic acid (PBA). Proximity of enzyme and LC ensures that H+ can be detected by the pH-sensitive LC before it is neutralized by buffer. Thus, the presence of OPs can be reported as color change in LC when they undergo enzymatic hydrolysis. For paraoxon detection, we can reach a limit of detection (LOD) of 1μM by using the naked eye. This type of LC-based biosensor also shows high specificity and does not respond to imidacloprid and ampicillin. [Copyright &y& Elsevier]

Abstract: A liquid crystal (LC)-based optical sensor has been developed to detect vaporous butylamine in air. This LC sensor doped with lauric aldehyde (LA) shows fast and distinct bright-to-dark optical response to butylamine vapor. For example, when the LA doping concentration is 0.1wt%, the LC shows a rapid bright-to-dark optical response within 2min after it is exposed to 10ppmv of butylamine. This optical response is attributed to an orientational transition of LC triggered by a reaction between LA and butylamine. This LC sensor also exhibits reversibility after the sensor is exposed to open air. In addition to primary amines (such as butylamine and octylamine), this LC-based sensor responds to secondary amines (such as diisopropylamine), but the detection limit is 200ppmv, which is much higher than butylamine. [Copyright &y& Elsevier]

Abstract: We report a functional protease assay in which liquid crystals (LCs) are used as signal reporters to transduce the test results into optical signals. In this assay, an oligopeptide substrate (CLSELDDRADALQAGASQFESSAAKLKRKYWWKNLK) is used as a probe. This oligopeptide can be cleaved by α-chymotrypsin at multiple locations and become smaller fragments after the cleavage. When the original oligopeptide is immobilized on a solid surface, its long flexible oligopeptide chain is able to influence the orientation of a thin layer of LC supported on the surface, as is evident as a bright spot on the surface. In contrast, when the shorter oligopeptide fragments are immobilized on the same surface, their shorter, less flexible chains cannot disrupt the orientation of LC, and a dark spot is observed. On the basis of the dark or bright signal from LC, α-chymotrypsin in buffer solution or complex media such as chicken broth can be detected by using the naked eye. However, when the incubation time is 3h, the limit of detection (LOD) for α-chymotrypsin in buffer solution is 50ng/mL, whereas that in chicken broth is only 500ng/mL. Unlike traditional antibody-based assays which show little difference between active and inactive α-chymotrypsin, only active protease can be detected in this assay. This study shows the potential utility of LCs for detecting functional proteases with good specificity and sensitivity. [Copyright &y& Elsevier]

Abstract: Immunobiosensors are emerging as powerful tools for diagnostic applications. In this paper, we exploit optical properties of liquid crystal (LC) and the specific epitope–antibody interaction to develop an optical immunobiosensor which can be used to detect monoclonal anti-FLAG M2, a model antibody. The sensitive layer of this immunobiosensor is a monolayer of immobilized oligopeptide CDYKDDDDK (FLAG) at an LC/aqueous interface. The linear oligopeptide can function as an epitope which can be recognized by anti-FLAG M2. When the LC is modified with 50μM of FLAG and then exposed to an aqueous solution containing anti-FLAG, anti-FLAG binds to the immobilized FLAG epitope and triggers orientational transition of LC. Because of the optical birefringence of the LC, the orientational transition is accompanied by changes in the optical images of LC from dark to bright under crossed polarizers. The detection limit for the system is 27ng/mL of anti-FLAG, and the response time is <1h. The binding of anti-FLAG to its motif FLAG oligopeptide is also very specific. When a variant epitope CDAKDDDDK is used, no apparent optical response can be observed after the addition of anti-FLAG. [Copyright &y& Elsevier]

Abstract: Materials with chemical micropatterned surface have broad applications in many fields. In this article, we report a simple one-step UV lithography method to activate inert hydrocarbon monolayers for spontaneous formation of water and covalently immobilized protein micropatterns on the surface. Two types of hydrocarbon monolayers including octadecyltrichlorosilane (OTS) on silicon oxide and 1-hexadecene on hydrogen-terminated silicon were studied. It was found that after UV modifications, water can form micropatterns spontaneously on both surfaces. Furthermore, when protein solutions were used, covalently immobilized protein micropatterns can be formed. Our XPS results and controlled reducing experiments showed that UV exposure transformed inert monolayers into active surfaces with aldehyde groups, which are responsible for the covalent immobilization of proteins. The method reported herein can be applied under ambient conditions without having a high vacuum system. It can also be extended to pattern other biomolecules bearing amine groups. [Copyright &y& Elsevier]

Abstract: This paper reports colorimetric responses of several metal phthalocyanines (MPcs), and MPc-doped polymers to primary amines. Among all MPcs tested, only FePc shows promise as a good candidate for detecting primary amines. In toluene, FePc shows a distinct color change from colorless to deep green upon addition of hexylamine. This colorimetric response is also highly specific. FePc does not respond to secondary amines, tertiary amines or other interferents tested in the study. We also doped several transparent polymers, poly(vinylalcohol) (PVA), Norland Optical Adhesive 65 (NOA65), and poly(dimethylsiloxane) with FePc and studied their colorimetric responses to hexylamine. Although they all exhibit color changes from transparent to green upon exposure to hexylamine, we find that only PDMS doped with FePc shows a selective and reversible response to hexylamine. Thus, FePc-doped PDMS may be coated onto protective suits or safety goggles to offer real-time information about amine exposure. [Copyright &y& Elsevier]

Abstract: We develop a liquid crystal (LC)-based optical sensor for detecting glutaraldehyde vapor by using real-time orientational responses of 4-cyano-4′-pentylbiphenyl (5CB) to glutaraldehyde. The sensor comprises a thin layer of 5CB (∼20μm) supported on an amine-decorated surface. When a glutaraldehyde molecule diffuses through the layer of 5CB, it reacts with a surface amine group and forms an imine bond. Subsequently, the resulting free aldehyde group from the glutaraldehyde molecule triggers an orientational transition of 5CB, which manifests as an optical signal visible to the naked eye. Because the performance of the LC-based sensor critically depends on the diffusion of glutaraldehyde in 5CB, we also measured the solubility and diffusivity of glutaraldehyde in 5CB. Based on the diffusivity, an optimal LC sensor with a 20-μm-thick film of 5CB can respond to 207ppmv glutaraldehyde within 20s and shows a full response in 4min. It also shows good specificity. Only a very weak response is observed when this sensor is exposed to acetic acid, and no response is recorded for methanol, ethanol or formaldehyde. [Copyright &y& Elsevier]

Abstract: Transforming growth factor-beta1 (TGF-β1) mediates expression of collagen 1A2 (Col 1A2) gene via a synergistic cooperation between Smad2/Smad3 and Sp1, both act on the Col 1A2 gene promoter. In our previous study, we reported that a retinoic acid derivative obtained from Phellinus linteus (designated PL) antagonizes TGF-β-induced liver fibrosis through regulation of ROS and calcium influx. In this continuing study we seek further the effect of PL on the Smad signaling pathway. We used a Col 1A2 promoter-luciferase construct to study the action of PL on Smad through TGF-β. We found that PL decreases the promoter activity of Col 1A2, hinders the translocalization of phosphorylated Smad2/3–Smad 4 complex from cytosol into nucleus and inhibits Sp1 binding activity. These results suggest that PL inhibits TGF-β1-induced Col 1A2 promoter activity through blocking ROS and calcium influx as well as impeding Sp1 binding and translocalization of pSmad 2/3–Smad4 complex into nucleus. [Copyright &y& Elsevier]

Abstract: Transforming growth factor-beta1 (TGF-β1) mediates the regulation of extracellular matrix via reactive oxygen species (ROS) and calcium influx, both are activators of hepatic stellate cells (HSC) which play a critical role in hepatic fibrogenesis. Hence one can use ROS assay as the main screening tool for molecules that might antagonize the process of liver fibrosis. A retinoic acid derivative isolated from the mycelium of Phellinus linteus that down-regulates ROS generation and calcium influx in HSC-T6 cells was thus obtained in our screening process. The retinoic acid derivative also reverses an early liver fibrosis, as assayed by liver contents of hydroxyproline, α-smooth muscle actin (α-SMA), and collagen 1A2, in an early liver fibrosis model we established previously where an inducible expression vector containing a TGF-β gene was hydrodynamically transferred into a testing animal. Retinoic acid derivative thus acts both in vitro and in vivo to prevent liver fibrosis at an early phase. [Copyright &y& Elsevier]

Abstract: This paper reports an investigation of the immobilization of glycine (Gly), glycyl-glycine (Gly-Gly), and glycyl-glycyl-glycine (Gly-Gly-Gly) on silica substrates (colloidal silica, silicon wafer, and glass slides) decorated with aldehyde functional groups. It is found that the density of Gly or oligoglycines immobilized on the surface can be greatly enhanced by using higher ionic strength (∼1M) and a reaction temperature of 50°C. High ionic strength was used to screen the electrostatic repulsion caused by the negatively charged carboxylate groups of Gly or oligoglycines, while higher temperature was needed to increase the reaction rates. It is also found that when a thin layer of nematic liquid crystal 4-pentyl-4′-cyano-biphenyl (5CB) was supported on a Gly or oligoglycine-decorated surface, the orientation of 5CB changed from planar to homeotropic (perpendicular to the surface) over a period of 24h. Furthermore, the switching time decreased when the surface density of oligoglycines was increased, and when the length of oligoglycines was increased by one or two Gly residues. The kinetic information provides a means to distinguish Gly, Gly-Gly, and Gly-Gly-Gly that only differ by a single Gly without using fluorescence or radioactive labeling. This method also has good spatial resolution over a large area that permits the detection of multiple oligoglycines patterned on the same surface. [Copyright &y& Elsevier]

Smectic liquid crystals form stable, micrometer-thick films when deposited onto the surfaces of solids. In this paper, we report that orientational transitions of thin films of the smectic liquid crystal (LC), 4′-octyl-4-biphenyl-carbonitrile (8CB) supported on surfaces presenting copper ions can be exploited to detect the presence of organophosphonate compounds at parts-per-billion (ppb) levels in gas phases. The orientational transition of the 8CB is driven by the competitive binding of the nitrile groups of 8CB and dimethyl methyl phosphonate (DMMP) for the surface-immobilized copper ions. Because the orientational transition of the LC can be observed by using a polarizing film and the naked eye, this detection scheme does not require complex instrumentation to transduce the signal. The film of LC responds to 10 ppbv of DMMP and the initial response time is approximately 20 s. The system is also demonstrated to exhibit molecular specificity. The LC does not respond to gaseous streams containing 1% of the saturated vapor concentrations of ethanol (770 ppm), hexane (1990 ppm) and acetone (3020 ppm) and 75% relative humidity of water. [Copyright &y& Elsevier]

Cyclic voltammetry experiments at various electrolyte solution concentrations (0.001–0.1 M) and scan rates (1 to 5 mV s−1) have been performed to study the electrical double layer (edl) formation in nanostructured carbon aerogel. The results show that carbon aerogel is a good edl capacitor and can be further divided into mesoporous and microporous capacitors. According to the experiments, the mesoporous capacitor shows a fast charging/discharging response and is only minimally affected by the electrolyte concentration and scan rate. Therefore, the specific capacitance of the mesoporous capacitor is found to be constant over a wide range of applied electrical potentials. On the other hand, the microporous capacitor shows a slow charging/discharging response and its capacitance strongly depends on the electrolyte concentration and potential. Unlike previous experiments, in which only a flat minimum was observed at the point of zero charge (pzc), in the current study, a deep minimum is observed near the pzc at low electrolyte concentration if a slow scan rate is used. This unique feature is a result of edl overlapping in the micropores and is consistent with the predictions by the Gouy–Chapman model employed in this study. Based on this behavior, a new approach is suggested for pzc measurements of solid porous materials for which a large portion of the surface area is in the micropore region. [Copyright &y& Elsevier]

Electrosorption is generally defined as potential-induced adsorption on the surface of charged electrodes. After polarization of the electrodes, ions are removed from the electrolyte solution by the imposed electric field and adsorbed onto the surface of the electrodes. Experimental and modeling studies were conducted using two types of carbon aerogel composites of different surface areas to provide a better understanding on the mechanisms of electrosorption. The experimental results revealed that no significant specific adsorption of F− ions occurred, while strong specific adsorption was observed for NO3− and Cu2+ ions. In addition, although the two types of carbon aerogel electrodes had different surface areas, their capacities were found to be very similar because of the electrical double-layer overlapping effect in micropores. An electrical double-layer model developed in our previous work (16), in which the electrical double-layer overlapping correction is included, is expanded in the present work by considering the effect of the specific adsorption on the electrosorption process. Modeling results were compared with experimental data obtained under various conditions. When the overlapping effect and specific adsorption were considered, the model provided results that were in good agreement with experimental data. [Copyright &y& Elsevier]

Micrometer-sized, periodic protein lines printed on a solid surface cause interference color which is invisible to the naked eye. However, the interference color can be amplified by using a thin layer of liquid crystal (LC) covered on the surface to form a phase diffraction grating. Strong interference color can thus be observed under ambient light. By using the LC-amplified interference color, we demonstrate naked-eye detection of a model protein-immunoglobulin G (IgG). Limit of detection can reach 20 μg/ml of IgG without using any instrumentation. This detection method is potentially useful for the development of low-cost and portable biosensors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oligomerization of aniline takes place near neutral pH. • Only 800 ppm H 2 O 2 and 2 ppm Fe-TAML are needed to treat 1000 ppm aniline. • The treatment requires much less H 2 O 2 than other advanced oxidation processes. • Aniline oligomers can be removed as precipitation from wastewaters. • No secondary waste is produced from the treatment of aniline. Aniline is a nitrogen-containing compound that contributes to both total organic carbon (TOC) and total nitrogen (TN) in wastewaters. Herein, we focus on converting aniline into oligomers, which aggregate into solid particles and can be separated from the wastewaters. By using this strategy, we can remove not only aniline but also TOC and TN in the wastewater without producing any secondary wastes. In this reaction, aniline is first reacted with H 2 O 2 in the presence of Iron-tetraamidomacrocyclic ligand (Fe-TAML) near a neutral pH. Only 800 ppm of H 2 O 2 and 2 ppm of Fe-TAML are needed to react with 1000 ppm of aniline at pH 8. After 2 days of reaction, solid particles are produced, and they can be filtered out with a membrane. The treatment efficiency can be further improved by lowering the pH to 6. Under this condition, the solid particles are big enough to settle under gravity in one day. After that, the top-layer solution can be separated from the solid particles. Following the oxidation- settling strategy, aniline, TOC, and TN of the decanted solution are reduced to 27.0, 99.0, and 29.0 ppm, respectively. This new strategy is effective in aniline removal with minimal H 2 O 2 and catalyst usages. [ABSTRACT FROM AUTHOR]

Abstract: Conventional immunoassays are often fluorescence- or enzyme-based and require additional readout systems. Here, we report a liquid crystal (LC)-based immunoassay that features a new signal transduction mechanism, whereby the test results appear as colorful spots and can be viewed with the naked eye directly. By using the different colors of LC spots, we can estimate the range of anti-hepatitis B surface antigen concentrations between 300 and 15nM. Because additional labeling process and readout systems are not required in this immunoassay, it is more suitable for point-of-care diagnosis of hepatitis B in resource-limited regions. [Copyright &y& Elsevier]

• A liquid crystal-based protease inhibition assay is developed. • This assay is used to assess inhibition efficiency of a protease inhibitor pefabloc. • IC 50 value of pefabloc can be detected by using the color of liquid crystal. • The assay provides detailed information about the transition period from reversible to irreversible inhibition. • Pefabloc inhibits protease activity irreversibly if the incubation time is more than 60 min. Protease inhibitors are essential drug molecules which can be used for treatments of protease-related diseases. Herein, we report an LC-based protease inhibition assay built inside a millifluidic device. This assay can be used to study the inhibition efficiency and reversibility of pefabloc (a serine protease inhibitor) against proteases. LC is employed for the detection of peptide fragments produced from protease activity inside the millifluidic device. LC gives a bright spot when the amount of peptide fragment exceeds a minimum value. By using this assay, we find that IC 50 value of pefabloc for the immobilized protease is 0.45 mg/mL, which is lower than the IC 50 value of pefabloc (0.90 mg/mL) obtained in a homogeneous assay. Moreover, proteases can be immobilized on the millifluidic device to build a heterogeneous protease assay. In this assay, pefabloc blocks the immobilized protease irreversibly after 60 min, which is longer than that in a homogenous protease assay. This reversibility study provides useful information about the transition period of pefabloc from reversible to irreversible inhibition. This protease inhibition assay is potentially useful for high throughput screening of unknown proteases and their inhibitor in a small sample volume. Moreover, this method can be used for dosage test of novel drug molecules which are protease inhibitors. [ABSTRACT FROM AUTHOR]

Production of esters from the acetone-butanol-ethanol (ABE) fermentation by Clostridium often focuses on butyl butyrate, leaving acetone as an undesired product. Addition of butyrate is also often needed because ABE fermentation does not produce enough butyrate. Here we addressed the problems using Clostridium beijerinckii BGS1 that preferred to produce isopropanol instead of acetone, and co-culturing it with Clostridium tyrobutyricum ATCC 25,755 that produced butyrate. Unlike acetone, isopropanol could be converted into ester using lipase and acids. C. tyrobutyricum ATCC 25,755 produced acids at pH 6, while C. beijerinckii BGS1 produced mainly solvents at the same pH. When the two strains were co-cultured, more butyrate was produced, leading to a higher titer of esters than the mono-culture of C. beijerinckii BGS1. As the first study reporting the production of isopropyl butyrate from the Clostridium fermentation, this study highlighted the potential use of lipase and co-culture strategy in ester production. [ABSTRACT FROM AUTHOR]

Many volatile organic compounds (VOCs) are hazardous to human health and their concentrations need to be monitored over a large area. However, most chemical sensors can only be used for point detection. In this paper, we report a method to obtain a two-dimensional (2D) concentration profile of toluene vapor by using polymer-stabilized liquid crystals (PSLCs). After the PSLC sample is exposed to toluene vapor ranging from 9300 to 2800 ppm, the PSLC changes its interference color according to different local toluene concentrations. By using the interference color, we can obtain a 2D concentration profile of toluene inside the PSLC and study the diffusion of toluene inside the PSLC in great detail. We also determine the diffusion coefficient of dissolved toluene inside the PSLC to be 1.01 × 10−6 cm2 s−1. [ABSTRACT FROM AUTHOR]

Tropical cyclone (TC) activities in the North Indian Ocean (NIO) peak in May during the pre-monsoon period, but the TC frequency shows obvious inter-annual variations. By conducting statistical analysis and dynamic diagnosis of long-term data from 1948 to 2016, the relationship between the inter-annual variations of Indian Ocean SST and NIO TC genesis frequency in May is analyzed in this paper. Furthermore, the potential mechanism concerning the effect of SST anomaly on TC frequency is also investigated. The findings are as follows: 1) there is a broadly consistent negative correlation between NIO TC frequency in May and SST in the Indian Ocean from March to May, with the key influencing area located in the southwestern Indian Ocean (SWIO); 2) the anomalies of SST in SWIO (SWIO-SST) are closely related to a teleconnection pattern surrounding the Indian Ocean, which can significantly modulate the high-level divergence, mid-level vertical motion and other related environmental factors and ultimately influence the formation of TCs over the NIO; 3) the increasing trend of SWIO-SST may play an essential role in the downward trend of NIO TC frequency over the past 69 years. [ABSTRACT FROM AUTHOR]

Chlorophenols have a strong medicinal smell and can be detected by the human nose at parts-per-million levels. Therefore, continuous monitoring of chlorophenols in water supplies is highly important. Herein, we reported a microfluidic sensor which can be used to detect 2,4-dichlorophenol (2,4-DCP) in real time with a limit of detection of around 0.1 ppm. The microfluidic sensor is a membrane-less galvanic cell which consists of two laminar flows running in parallel inside a straight channel. The sensor measures the potential difference between a solution containing 2,4-DCP and a reference solution containing acetate buffer. In a continuous-flow mode, the cell potential is proportional to the concentration of 2,4-DCP. To render specificity for the sensor, we incorporate a pre-treatment section where the incoming solution containing 2,4-DCP is split into two streams. One of the streams is brought into contact with cross-linked laccase aggregates (which catalyzes the hydrolysis of 2,4-DCP) and the second stream is taken as a reference solution. By comparing the potential difference between the two streams, we can determine the concentration of 2,4-DCP with high specificity. The microfluidic sensor platform is potentially useful for real-time detection of micropollutants present in aquatic systems with high sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Butanol toxicity, oxygen sensitivity, and high substrate cost limit wider applications of the traditional Clostridium acetone-butanol-ethanol (ABE) fermentation. In this study, a wild-type Clostridium beijerinckii strain was partnered with an engineered Escherichia coli strain to improve the ABE fermentation through a co-culture. Butanol and butyrate produced by C. beijerinckii were converted into butyl butyrate – a product that can be in situ removed to reduce product toxicity – by expressing a CoA transferase and an alcohol acyltransferase in E. coli. When integrated with a pretreatment technology and using commercial cellulase, the co-culture produced 1280 mg/L butyl butyrate from rice straw in bioreactors, without the need of maintaining a strict anaerobic condition. As a process harnessing both the genetic tractability of E. coli and the superior acid- and alcohol-producing ability of Clostridium , this co-culture fermentation will be useful in producing valuable esters from low-cost waste streams. [Display omitted] • E. coli was engineered to express a CoA transferase and an alcohol acyltransferase. • Butyl butyrate was produced by the co-culture from lignocellulosic biomass. • Aerobic co-culture of E. coli and Clostridium was achieved. [ABSTRACT FROM AUTHOR]

Clostridia can produce hydrogen (a renewable-biofuel) from crude glycerol (CG). Reportedly, the indigenous CG-impurities (eg.methanol, soap and salt) interfere with clostridial-process, and reduces hydrogen production. Thus, it is important to develop a robust bioprocess to directly utilize native-CG for hydrogen production. In this study, among four Clostridia tested, Clostridium beijerinckii G117 is selected based on its high hydrogen (>290 mL/g) production from CG. Furthermore, optimization of process-parameters enhances hydrogen production from strain G117 by ∼5 fold from 1195 ± 45 to 5893 ± 25 mL/L with 2.16 mol/mol yield. The order of impact of process-parameters (optimum value in parenthesis) on hydrogen production is: CG concentration (12.5 g/L)>inoculum size (10%v/v)>inoculum age (12 h)>temperature (39 °C)>initial medium-pH (6.4)>L-cysteine (1 g/L)>operational volume (30 mL)>agitation rate (150 rpm). Notably, this optimized bioprocess records >90% efficiency by determining total mass and electron balances. Interestingly, this optimized bioprocess retains adequate robustness to yield 1.94–2.02 mol/mol hydrogen with elevated CG-impurities including alcohols/salts/surfactants. [Display omitted] • Clostridium beijerinckii G117 produces >290 mL hydrogen per gram crude glycerol (CG). • Optimization of process with strain G117 enhances hydrogen production to >520 mL/g CG. • Along with hydrogen, strain G117 produces 0.7 g/L acetic, and 2.71 g/L butyric acids. • Strain G117 is resistant to many CG-impurities including alcohols/salts/surfactants. • It renders an efficient (>90%) and robust-bioprocess to yield ∼2 mol H2 /mol Glycerol. [ABSTRACT FROM AUTHOR]

Xylooligosaccharides (XOS) are emerging prebiotics which can be produced from lignocellulosic biomass including agro-residues and hardwood. In this study, we report the production of XOS from thermal-alkali pretreated hardwood such as mahogany and mango by using a purified xylanase from Clostridium strain BOH3. In the first approach, pure xylan is extracted from mahogany and mango hardwood and then the pure xylan is hydrolyzed by using the xylanase. In this case, 572 and 504 mg XOS/g pure xylan were obtained from mahogany and mango woods, respectively. In the second approach, the same xylanase is employed to hydrolyze sawdust of hardwood after different types of pretreatments. After a thermal (121 °C for 15 min) pretreatment under a mild alkaline (0.05N NaOH) condition, the pretreated mahogany and mango sawdust can be utilized directly to produce 89.5 and 67.6 mg XOS/g pretreated sawdust, respectively. XOS produced from the pretreated sawdust show strong prebiotic effects on Bifidobacteria and Lactobacilli . This report shows the possibility of producing XOS from pretreated woody wastes without using pure xylan as a substrate. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs), chemicals commonly used as flame-retardants in consumer products, are emerging persistent organic pollutants that are ubiquitous in the environment. In this study, we report a PBDE-respiring isolate - Dehalococcoides mccartyi strain GY50, which debrominates the most toxic tetra- and penta-BDE congeners (∼1.4 µM) to diphenyl ether within 12 days with hydrogen as the electron donor. The complete genome sequence revealed 26 reductive dehalogenase homologous genes ( rdhAs), among which three genes ( pbrA1, pbrA2 and pbrA3) were highly expressed during PBDE debromination. After 10 transfers of GY50 with trichloroethene or 2,4,6-trichlorophenol as the electron acceptor instead of PBDEs, the ssrA-specific genome island ( ssrA-GI) containing pbrA1 and pbrA2 was deleted from the genome of strain GY50, leading to two variants (strain GY52 with trichloroethene, strain GY55 with 2,4,6-trichlorophenol) with identically impaired debromination capabilities (debromination of penta-/tetra-BDEs ceased at di-BDE 15). Through analysis of Illumina paired-end sequencing data, we identified read pairs that probably came from variants that contain ssrA-GI deletions, indicating their possible presence in the original strain GY50 culture. The two variant strains provide real-time examples on rapid evolution of organohalide-respiring organisms. As PBDE-respiring organisms, GY50-like strains may serve as key players in detoxifying PBDEs in contaminated environments. [ABSTRACT FROM AUTHOR]

Hollow cross-linked enzyme aggregates of laccase (h-CLEA laccase) can be prepared by employing a millifluidic reactor carrying two coaxial laminar flows. In a confluence zone where acetonitrile and an aqueous solution of laccase meet, diffusion of acetonitrile into the aqueous solution gives rise to rapid precipitation of laccase aggregates at the water/acetonitrile interface, as is evidenced by fluorescence images. By controlling the flow rates carefully in the laminar flow regions, h-CLEA laccase around 220 ± 10 nm can be obtained, and the size of the h-CLEA laccase increases with increasing flow rates of both solutions. The h-CLEA laccase particles are distinctly different from CLEA laccase prepared in batch processes. The former only consist a crust of cross-linked enzymes (with a hollow core) whereas the latter has a highly porous structure. When the h-CLEA laccase is used as biocatalysts, their activity (0.26 U/mg) is comparable to that of free enzymes at neutral pH due to the hollow structure. Moreover, the activity of h-CLEA laccase is higher than that of free laccase at high pH. For example, trypan blue (a dye molecule) can be decolorized completely in the presence of h-CLEA laccase within 270 min even at pH 10.0, at which the free enzyme completely loses its activity. Because of their uniform sizes, h-CLEA laccase can be trapped in a membrane for continuous degradation of trypan blue up to 96 h without losing any activity. This study shows the superiority of h-CLEA laccase compared to other types of immobilized enzymes. [ABSTRACT FROM AUTHOR]

Entrapment of enzymes in calcium alginate beads is a popular enzyme immobilization method. However, leaching of immobilized enzymes from the alginate beads is a common problem because enzyme molecules are much smaller than the pore size of alginate beads (∼200 nm). To address this issue, we employ a millifluidic reactor to prepare cross-linked cellulase aggregate (XCA) colloids with a uniform size (∼300 nm). Subsequently, these colloids are immobilized in calcium alginate beads as biocatalysts to hydrolyze cellulose substrates. By using fluorescent microscopy, we conclude that the immobilized XCA colloids distribute uniformly inside the beads and do not leach out from the beads after long-term incubation. Meanwhile, the pore size of the alginate beads is big enough for the cellulose substrates and fibers to diffuse into the beads for hydrolysis. For example, palm oil fiber and microcrystalline cellulose can be hydrolyzed within 48 h and release reducing sugar concentrations up to 2.48 ± 0.08 g/l and 4.99 ± 0.09 g/l, respectively. Moreover, after 10 cycles of hydrolysis, 96.4% of the XCA colloids remain inside the alginate beads and retain 67% of the original activity. In contrast, free cellulase immobilized in the alginate beads loses its activity completely after 10 cycles. The strategy can also be used to prepare other types of cross-linked enzyme aggregates with high uniformity. [ABSTRACT FROM AUTHOR]

Fe−TAML is a well‐known green catalyst for bleaching and wastewater treatments. Quantitative analysis of Fe−TAML is important to understand its activity and lifetime in these applications. However, because of its sub‐parts‐per‐million dosage and the presence of interfering substances, it is very challenging to detect Fe−TAML specifically and quantitatively at this level. To overcome these issues, we develop a quantitative assay for Fe−TAML, which is based on its catalytic reaction with a blue dye (Reactive Blue 19) and H2O2. This assay is highly specific, and shows no interference for iron species. Moreover, the colorimetric assay can be carried out for fast screening of Fe−TAML with a limit of detection (LOD) of 0.39±0.08 μg L−1. Finally, this assay was successfully applied to understand the stability of Fe−TAML under various conditions, and monitoring the activity of Fe−TAML during wastewater treatments. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the importance of depth of invasion (DOI) in patients with pathologically low‐risk feature stage I oral squamous cell carcinoma (OSCC) managed by primary tumor resection alone. Methods: Patients with stage I OSCC, at pathologically low risk, underwent primary tumor resection without neck dissection were enrolled retrospectively between 2007 and 2015. Low risk was defined as the absence of positive or close margins, lymphovascular invasion, perineural invasion, worst pattern of invasion‐5, and poor differentiation in histologic grade. The primary endpoints included overall survival (OS), cancer specific survival (CSS), local recurrence free survival (LRFS), and regional recurrence free survival (RRFS). A nomogram based on the DOI was established for predicting RRFS. Results: A total of 198 patients were enrolled in this study. DOI was the only prognosticator to achieve statistical significance in all primary endpoints according to univariate analysis. Patients with DOI <3 mm tumor showed better five‐year OS, CSS, LRFS, and RRFS than those with DOI ≥3 mm tumor. The concordance index of the nomogram model without DOI was 0.684, which could increase to 0.733 when DOI was included in the calculation. Conclusion: Patients with pathologically low‐risk stage I OSCC correlate with a higher chance in occult neck metastasis if increasing DOI (≥3 mm) is noticed. Indeed, the chance of occult neck metastasis is significantly higher in this group (14% vs. 2%) than in those with DOI <3 mm. Elective neck dissection is advised if DOI is ≥3 mm to achieve better clinical outcomes. Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Vanillin is an aromatic organic compound that is widely used in the food and cosmetics industries. The development of a simple and rapid method for the naked-eye detection of vanillin is essential for monitoring the vanillin production process. In this study, liquid crystal 5CB (4-cyano-4'-pentylbiphenyl) is doped with acetone and used as a sensing platform to detect vanillin in alkaline solutions with high specificity for the first time. Before the addition of vanillin, the acetone-doped 5CB adopts a homeotropic orientation and appears dark due to the formation of an electrical double layer (EDL) at the 5CB/water interface. In the presence of vanillin, it forms a complex with acetone inside 5CB, disrupting the EDL and the homeotropic orientation of 5CB. The event leads to a dark-to-bright transition which can be used to quantify the concentration of vanillin in a range between 0.1 and 25 mg/L. The limit of detection (LOD) for the vanillin sensor is 0.06 mg/L. As a proof of concept, the sensor is employed to monitor the vanillin concentration during oxidation of coniferyl alcohol. In the presence of 5000 mg/L of H 2 O 2 and 1 mg/L iron tetraamidomacrocyclic ligand (Fe-TAML), 1750 mg/L of coniferyl alcohol can be converted to 393.0 mg/L of vanillin after a 30-min reaction at room temperature. This study demonstrates potential applications of the acetone-doped liquid crystal sensors for monitoring the production of vanillin under various conditions. [Display omitted] • An acetone-doped liquid crystal sensor for vanillin detection is developed. • The limit of detection (LOD) for vanillin is 0.06 mg/L with high specificity. • Coniferyl alcohol can be oxidized to vanillin by using H 2 O 2 and a catalyst. • The sensor can be used to monitor the production of vanillin from coniferyl alcohol. [ABSTRACT FROM AUTHOR]

Detection methods based on aptamer probes have great potential and progress in the field of rapid detection of heavy metal ions. However, the unstable conformation of aptamers often results in poor sensitivity due to the dissociation of aptamer-target complex in real environments. In this study, we developed a locking aptamer probe and combined it with AgInZnS quantum dots for the first time to detect cadmium ions. When cadmium ions are combined with the probe, the cadmium ions are fixed in the core-locking position, forming a stable cavity structure. The limit of detection (LOD) was achieved at a concentration of 6.9 nmol L−1, with a broad detection range from 10 nmol L−1 to 1000 μmol L−1, and good recovery rates (92.93%–102.8 %) were achieved in aquatic product testing. The locking aptamer probe with stable conformation effectively enhances the stability of the aptamer-target complex and remains good stability in four buffer environments as well as a 600 mmol L−1 salt solution; it also exhibits good stability at pH 6.5–7.5 and temperatures ranging from 25 °C to 35 °C. Overall, our study presented a general, simple, and cost-effective strategy for stabilizing aptamer conformations, and used for highly sensitive detection of cadmium ions. A lock-type aptasensor detection of cadmium to enhances the stability of the aptamer-target complex and remains good stability in four buffer environments. [Display omitted] • Truncated and optimized to obtain a locking aptamer probe with good affinity and spatial constraint ability. • For the first time, a detection probe for the specific recognition of cadmium ions was developed and designes. • The lock-type aptasensor has outstanding specificity and the sensitivity for detecting cadmium ions can reach the nmol/L level. • The lock-type aptasensor greatly improves the stability of aptamers in different buffer environments and high-salt environments. [ABSTRACT FROM AUTHOR]