Does the active hydrogen atom in the hydantoin anion affect the physical properties, CO2 capture and conversion of ionic liquids?

Compared to the effect of the active hydrogen atom in the cation in protic ionic liquids (ILs) on their properties and applications, there are very few reports on the role of the active hydrogen atom in the anion. In order to better understand the role of the active hydrogen atom in the anion, the physical properties, CO2 capture and conversion of three hydantoin-based anion-functionalized ILs ([P4442][Hy], [P4442]2[Hy], and [HDBU][Hy]) have been investigated via experiments, spectroscopy, and DFT calculations in this work. The results show that the active hydrogen atom in the anion can form anionic hydrogen bonding networks, which significantly increase the melting point and viscosity and decrease the basicity of the IL, thereby weakening its ability to capture and convert CO2. Interestingly, [P4442][Hy] undergoes a solid/liquid two-phase transition during CO2 absorption/desorption due to the formation of quasi-intramolecular hydrogen bonding between the active hydrogen atom and the O- atom of the absorbed CO2, suggesting that the presence of the active hydrogen atom gives [P4442][Hy] the potential to be an excellent molecular switch. As there is no active hydrogen atom in the anion of [P4442]2[Hy], it shows excellent CO2 capture and conversion performance through the double-site interaction. [HDBU][Hy] shows the weakest catalytic CO2 conversion due to the presence of active hydrogen atoms on both its anion and cation. Therefore, the active hydrogen atom in the anion may play a more important role in the properties and potential applications of ILs than the active hydrogen atom in the cation.

Constructing a "micro-nano collaboration" network via disk-milling: Value-enhanced utilization of flexible temperature-resistant cellulose insulation films.

Cellulose is a sustainable natural polymer material that has found widespread application in transformers and other power equipment because of its excellent electrical and mechanical performance. However, the utility of cellulose materials has been limited by the challenge of balancing heat resistance with flexibility. On the basis of the preliminary research conducted by the research team, further proposals have been put forward for a method involving disk milling to create a "micro-nanocollaboration" network for the fabrication of flexible, high-temperature-resistant, and ultrafine fiber-based cellulose insulating films. The resulting full-component cellulose films exhibited impressive properties, including high tensile strength (22 MPa), flexibility (92-263 mN), remarkable electrical breakdown strength (39 KV/mm), and volume resistivity that meets the standards for insulation materials (4.92 × 1011 Ω·m). These results demonstrate that the proposed method can produce full-component cellulose insulation films that offer both exceptional flexibility and high-temperature resistance.

BDK inhibition acts as a catabolic switch to mimic fasting and improve metabolism in mice.

OBJECTIVE: Branched chain amino acid (BCAA) catabolic defects are implicated to be causal determinates of multiple diseases. This work aimed to better understand how enhancing BCAA catabolism affected metabolic homeostasis as well as the mechanisms underlying these improvements. METHODS: The rate limiting step of BCAA catabolism is the irreversible decarboxylation by the branched chain ketoacid dehydrogenase (BCKDH) enzyme complex, which is post-translationally controlled through phosphorylation by BCKDH kinase (BDK). This study utilized BT2, a small molecule allosteric inhibitor of BDK, in multiple mouse models of metabolic dysfunction and NAFLD including the high fat diet (HFD) model with acute and chronic treatment paradigms, the choline deficient and methionine minimal high fat diet (CDAHFD) model, and the low-density lipoprotein receptor null mouse model (Ldlr-/-). shRNA was additionally used to knock down BDK in liver to elucidate liver-specific effects of BDK inhibition in HFD-fed mice. RESULTS: A rapid improvement in insulin sensitivity was observed in HFD-fed and lean mice after BT2 treatment. Resistance to steatosis was assessed in HFD-fed mice, CDAHFD-fed mice, and Ldlr-/- mice. In all cases, BT2 treatment reduced steatosis and/or inflammation. Fasting and refeeding demonstrated a lack of response to feeding-induced changes in plasma metabolites including insulin and beta-hydroxybutyrate and hepatic gene changes in BT2-treated mice. Mechanistically, BT2 treatment acutely altered the expression of genes involved in fatty acid oxidation and lipogenesis in liver, and upstream regulator analysis suggested that BT2 treatment activated PPARα. However, BT2 did not directly activate PPARα in vitro. Conversely, shRNA-AAV-mediated knockdown of BDK specifically in liver in vivo did not demonstrate any effects on glycemia, steatosis, or PPARα-mediated gene expression in mice. CONCLUSIONS: These data suggest that BT2 treatment acutely improves metabolism and liver steatosis in multiple mouse models. While many molecular changes occur in liver in BT2-treated mice, these changes were not observed in mice with AAV-mediated shRNA knockdown of BDK. All together, these data suggest that systemic BDK inhibition is required to improve metabolism and steatosis by prolonging a fasting signature in a paracrine manner. Therefore, BCAA may act as a "fed signal" to promote nutrient storage and reduced systemic BCAA levels as shown in this study via BDK inhibition may act as a "fasting signal" to prolong the catabolic state.

High-Sensitivity Optical Fiber-Based Glucose Sensor Using Helical Intermediate-Period Fiber Grating.

An all-fiber glucose sensor is proposed and demonstrated based on a helical intermediate-period fiber grating (HIPFG) produced by using a hydrogen/oxygen flame heating method. The HIPFG, with a grating length of 1.7 cm and a period of 35 µm, presents four sets of double dips with low insertion losses and strong coupling strengths in the transmission spectrum. The HIPFG possesses an averaged refractive index (RI) sensitivity of 213.6 nm/RIU nm/RIU in the RI range of 1.33-1.36 and a highest RI sensitivity of 472 nm/RIU at RI of 1.395. In addition, the HIPFG is demonstrated with a low-temperature sensitivity of 3.67 pm/°C, which promises a self-temperature compensation in glucose detection. In the glucose-sensing test, the HIPFG sensor manifests a detection sensitivity of 0.026 nm/(mg/mL) and a limit of detection (LOD) of 1 mg/mL. Moreover, the HIPFG sensor exhibits good stability in 2 h, indicating its capacity for long-time detection. The properties of easy fabrication, high flexibility, insensitivity to temperature, and good stability of the proposed HIPFG endow it with a promising potential for long-term and compact biosensors.

Ultrasensitive refractometer based on helical long-period fiber grating near the dispersion turning point.

Precise and accurate measurements of the optical refractive index (RI) for liquids are increasingly finding applications in biochemistry and biomedicine. Here, we demonstrate a dual-resonance helical long-period fiber grating (HLPFG) near the dispersion turning point (DTP), which exhibits an ultrahigh RI sensitivity (∼25546 nm/RIU at ∼1.440). The achieved RI sensitivity is, to the best of our knowledge, more than one order of magnitude higher than a conventional HLPFG. The ultrahigh RI sensitivity can improve the RI measurement precision and accuracy significantly. Furthermore, ultralow wavelength shifts (nearly zero) with temperature and strain ranging from 20 to 100°C and 0 to 2226 µÎµ, respectively, are also demonstrated for the proposed HLPFG, which may be a good candidate for developing new low-cross-talk sensors.

All Fiber-Optic Immunosensors Based on Elliptical Core Helical Intermediate-Period Fiber Grating with Low-Sensitivity to Environmental Disturbances.

An all fiber-optic immunosensor based on elliptical core helical intermediate-period fiber grating (E-HIPFG) is proposed for the specific detection of human immunoglobulin G (human IgG). E-HIPFGs are all-fiber transducers that do not include any additional coating materials or fiber architectures, simplifying the fabrication process and promising the stability of the E-HIPFG biosensor. For human IgG recognition, the surface of an E-HIPFG is functionalized by goat anti-human IgG. The functionalized E-HIPFG is tested by human IgG solutions with a concentration range of 10-100 µg/mL and shows a high sensitivity of 0.018 nm/(µg/mL) and a limit of detection (LOD) of 4.7 µg/mL. Notably, the functionalized E-HIPFG biosensor is found to be insensitive to environmental disturbances, with a temperature sensitivity of 2.6 pm/°C, a strain sensitivity of 1.2 pm/µÎµ, and a torsion sensitivity of -23.566 nm/(rad/mm). The results demonstrate the considerable properties of the immunosensor, with high resistance to environmental perturbations, indicating significant potential for applications in mobile biosensors and compact devices.

Association of mitochondrial respiratory chain enzymes with the risk and mortality of sepsis among Chinese children.

BACKGROUND: Sepsis is a leading cause of pediatric morbidity and mortality worldwide. The aim of this study was to explore the association of decreased mitochondrial respiratory chain enzyme activities with the risk for pediatric sepsis, and explore their association with mortality among affected children. METHODS: A total of 50 incident cases with sepsis and 49 healthy controls participated in this study. The level of serum coenzyme Q10 was measured by high-performance liquid chromatography, and selected mitochondrial respiratory chain enzymes in WBC were measured using spectrophotometric. Logistic regression models were used to estimate odds ratio (OR) and 95% confidence interval (CI). RESULTS: The levels of CoQ10, complex II, complex I + III and FoF1-ATPase were significantly higher in healthy controls than in children with sepsis (p < 0.001, = 0.004, < 0.001 and < 0.001, respectively). In children with sepsis, levels of CoQ10 and complex I + III were significantly higher in survived cases than in deceased cases (p < 0.001). Per 0.05 µmol/L, 50 nmol/min.mg and 100 nmol/min.mg increment in CoQ10, complex I + III and FoF1-ATPase were associated with significantly lowered risk of having sepsis, even after adjusting for confounding factors (OR = 0.85, 0.68 and 0.04, p = 0.001, < 0.001 and < 0.001, respectively). Per 0.05 µmol/L and 50 nmol/min.mg increment in CoQ10 and complex I + III was associated with significantly lowered risk of dying from sepsis during hospitalization, and significance retained after adjustment (OR = 0.73 and 0.76, 95% CI: 0.59 to 0.90 and 0.64 to 0.89, p = 0.004 and 0.001, respectively) in children with sepsis. CONCLUSIONS: Our findings indicate the promising predictive contribution of low serum CoQ10 and complex I + III to the risk of pediatric sepsis and its associated mortality during hospitalization among Chinese children. Trial registration The trial was registered with www.chictr.org.cn , number ChiCTR-IOR-15006446 on May 05, 2015. Retrospectively registered.

Coupling Mixed Mode Chromatography/ESI Negative MS Detection with Message-Passing Neural Network Modeling for Enhanced Metabolome Coverage and Structural Identification.

A key unmet need in metabolomics continues to be the specific, selective, accurate detection of traditionally difficult to retain molecules including simple sugars, sugar phosphates, carboxylic acids, and related amino acids. Designed to retain the metabolites of central carbon metabolism, this Mixed Mode (MM) chromatography applies varied pH, salt concentration and organic content to a positively charged quaternary amine polyvinyl alcohol stationary phase. This MM method is capable of separating glucose from fructose, and four hexose monophosphates a single chromatographic run. Coupled to a QExactive Orbitrap Mass Spectrometer with negative ESI, linearity, LLOD, %CV, and mass accuracy were assessed using 33 metabolite standards. The standards were linear on average >3 orders of magnitude (R2 > 0.98 for 30/33) with LLOD < 1 pmole (26/33), median CV of 12% over two weeks, and median mass accuracy of 0.49 ppm. To assess the breadth of metabolome coverage and better define the structural elements dictating elution, we injected 607 unique metabolites and determined that 398 are well retained. We then split the dataset of 398 documented RTs into training and test sets and trained a message-passing neural network (MPNN) to predict RT from a featurized heavy atom connectivity graph. Unlike traditional QSAR methods that utilize hand-crafted descriptors or pre-defined structural keys, the MPNN aggregates atomic features across the molecular graph and learns to identify molecular subgraphs that are correlated with variations in RTs. For sugars, sugar phosphates, carboxylic acids, and isomers, the model achieves a predictive RT error of <2 min on 91%, 50%, 77%, and 72% of held-out compounds from these subsets, with overall root mean square errors of 0.11, 0.34, 0.18, and 0.53 min, respectively. The model was then applied to rank order metabolite IDs for molecular features altered by GLS2 knockout in mouse primary hepatocytes.

Magnetic field sensor based on helical long-period fiber grating with a three-core optical fiber.

A high sensitivity optical fiber magnetic field sensor is proposed and implemented by using a helical long-period fiber grating (HLPFG) based on a three-core fiber (TCF) bonded to a U-shaped aluminum (Al) wire. An electrical current flowing through the Al wire in a perpendicular magnetic field can generate Ampere force, which changes the distance between the two arms of the U-shaped Al wire. Thus, when the intensity and direction of the magnetic field change, the bending curvature of TCF-HLPFG bonded to the U-shaped Al wire varies with the change of Ampere force, which is represented as the shift of resonant wavelength in the spectrum. The as-fabricated sensor can respond to the magnetic field direction and the intensity with a range from -15 mT to 15 mT, and the measured sensitivity is 456.5 pm/mT with Al wire electrical current 1A. The proposed sensor has the advantages of low cost, nondestructive measurement method and ease manufacture, and is expected to be applied to weak magnetic field measurements.

Selective fiber Bragg grating inscription in four-core fiber for two-dimension vector bending sensing.

The paper presents selective fiber Bragg grating (FBG) inscription in four-core fiber based on a phase mask scanning method. The inscription factors are systematically investigated, which involves fiber core position and focused laser beam size in fiber, etc. Several specific inscriptions (including individual, dual and all inscriptions) are demonstrated. Two orthogonally positioned cores are selectively inscribed and applied to two-dimension vector bending measurement. The measured bending sensitivities of two FBGs range from -54.3 pm/m-1 to 52.2 pm/m-1 and -53.7 pm/m-1 to 52.8 pm/m-1, respectively. More importantly, it has been revealed that their sensitivities versus bending direction follow regular cosinoidal and sinusoidal distribution. The direction and amplitude of the vector bending can be recovered using measured central wavelength shifts of those two FBGs.

De novo lipogenesis is essential for platelet production in humans.

Acetyl-CoA carboxylase (ACC) catalyses the first step of de novo lipogenesis (DNL). Pharmacologic inhibition of ACC has been of interest for therapeutic intervention in a wide range of diseases. We demonstrate here that ACC and DNL are essential for platelet production in humans and monkeys, but in not rodents or dogs. During clinical evaluation of a systemically distributed ACC inhibitor, unexpected dose-dependent reductions in platelet count were observed. While platelet count reductions were not observed in rat and dog toxicology studies, subsequent studies in cynomolgus monkeys recapitulated these platelet count reductions with a similar concentration response to that in humans. These studies, along with ex vivo human megakaryocyte maturation studies, demonstrate that platelet lowering is a consequence of DNL inhibition likely to result in impaired megakaryocyte demarcation membrane formation. These observations demonstrate that while DNL is a minor quantitative contributor to global lipid balance in humans, DNL is essential to specific lipid pools of physiological importance.

Reducing carbon emissions from collaborative distribution: a case study of urban express in China.

The booming development of e-commerce has brought about rapid growth in the express delivery industry in China. However, urban express distribution is increasingly difficult and seriously affecting the traffic, safety, and environmental conditions of cities due to small, scattered end points, unreasonable allocation of resources, and seriously repeated resource waste. Therefore, there is an urgent need to solve the problems associated with the unreasonable resource allocation of express distribution. In the context of green logistics, a new mode of collaborative distribution based on intelligent end service station (IESS) is proposed. Following the measurement models of carbon emissions, before and after collaborative distributions are provided to prove the environmental benefits of the new mode. The influencing factors considered in the models are the average daily distribution volume, number of distribution sections, vehicle ownership of various types, and their capacity, use, fuel, and power consumption. To verify the models' validity, we conduct an empirical study of five express enterprises in China and make a comparative analysis on the results, which show that the implementation of collaborative distribution can extremely reduce carbon emissions and improve the overall load rate of vehicles. Specially, the use of new energy vehicles can contribute significantly to energy conservation and emissions reduction.

Weak feedback assisted random fiber laser from 45°-tilted fiber Bragg grating.

We have demonstrated the realization of a high-polarization random fiber laser (RFL) output based on the hybrid Raman and Erbium gain with the tailored effect provided by a 45°-tilted fiber Bragg grating (45°-TFBG), revealing an improvement in the polarization extinction ratio (PER) and achieving a PER of ~15.3 dB. The hybrid RFL system incorporating the 45°-TFBG has been systematically characterized. The random lasing wavelength can be fixed under the extremely weak feedback effect of the 45°-TFBG with reflectivity of 0.09%. In addition, numerical simulation has verified that the weak feedback can boost the random lasing emission with fixed wavelength using a power balance model, which is in good accordance with the experiment results.

Residual-stress-induced helical long period fiber gratings for sensing applications.

We demonstrate a high-efficiency grating fabrication system, which can be used to inscribe a high-quality helical long period fiber grating (HLPFG) on single-mode fiber by means of hydrogen-oxygen flame. Such the HLPFG can be produced in enormous quantities with a uniform grating parameters and good reproducibility of grating inscription. Possible mechanisms for refractive index modulation in the HLPFG can be attributed to residual stress concentration by solidifying the periodic twisting stress under a fused status of optical fiber. Moreover, the HLPFG exhibits an excellence performance of high temperature sensing with a high sensitivity of ~132.8 pm/°C and a measuring range from room temperature to 900 °C. Comparing to the traditional LPFG fabricated by CO2 laser or arc discharge technique, the HLPFG has a low the bending and tensile strain sensitivity of 1.94 nm/(1/m) and 1.41 pm/µÎµ, respectively. So the proposed HLPFG could have a great potential in special applications as optical high-temperature sensors.

Strain-based tunable optical microresonator with an in-fiber rectangular air bubble.

We demonstrate a strain-based fully tunable, near-lossless, whispering gallery mode (WGM) resonator made of an in-fiber rectangular air bubble, which is fabricated by splicing two segments of standard single-mode fibers. Such a resonator, with a 39 µm order radius and 1 µm order wall thickness, contributes to a high quality factor exceeding 106. The tuning in resonant wavelength is achieved by applying tensile strain to the resonator, and the voltage-tuning rate of the WGM resonance peaks is about 31.96 pm/V (strain-tuning rate ∼14.12 pm/µÏµ), and the corresponding tuning accuracy is better than 0.03 pm. Since the tensile strain applied on the resonator can reach 1000 µÏµ, the achievable total tunable bandwidth of ∼14.12 nm is more than two times that of its azimuthal free spectral range.

Study on vibration sensing performance of an equal strength cantilever beam based on an excessively tilted fiber grating.

An equal strength cantilever beam vibration sensor based on an excessively tilted fiber grating (Ex-TFG) with light intensity demodulation is proposed. The basic principles and sensing characteristics of vibration sensing of an equal strength cantilever beam and Ex-TFG, the combination of which is applied into vibration sensing, are analyzed. An Ex-TFG is attached to the middle axis of an equal strength cantilever beam. As the vibration of a piezoelectric ceramic causes the equal strength cantilever beam to deform, the same and uniform deformation also occurs on the Ex-TFG. Experimental results show that when the thickness of the equal strength cantilever beam is 0.3 mm and the Ex-TFG is at transverse electric (TE) polarization state, the sensing performance is the best, with the maximum acceleration sensitivity reaching 81.065 mv·m-1·s2, and the fast Fourier transform (FFT) main frequency components of the sensing signal accounting for more than 80%. In addition, this sensor is stable in sensing performance, easy in demodulation, simple in structure, high in sensitivity, and easy in manufacture, applicable for the sensing and on-line monitoring of low-frequency vibration signals.

Enzyme-functionalized thin-cladding long-period fiber grating in transition mode at dispersion turning point for sugar-level and glucose detection.

Enzyme-functionalized dual-peak long-period fiber grating (LPFG) inscribed in 80 - ? m -cladding B/Ge codoped single-mode fiber is presented for sugar-level and specific glucose detection. Before enzyme functionalization, the dual-peak LPFG was employed for refractive index sensing and sugar-level detection and high sensitivities of ? 4298.20 ?? nm / RIU and 4.6696 ?? nm / % were obtained, respectively. Glucose detection probe was attained by surface functionalization of the dual-peak LPFG via covalent binding with aminopropyl triethoxysilane used as a binding site. Optical micrographs confirmed the presence of enzyme. The surface-functionalized dual-peak LPFG was tested with D-(+)-glucose solution of different concentrations. While the peak 2 at the longer wavelength was suitable only to measure lower glucose concentration (0.1 to 1.6 ?? mg / ml ) recording a high sensitivity of 12.21 ± 0.19 ?? nm / ( mg / ml ) , the peak 1 at the shorter wavelength was able to measure a wider range of glucose concentrations (0.1 to 3.2 ?? mg / ml ) exhibiting a maximum resonance wavelength shift of 7.12 ± 0.12 ?? nm / mg / ml . The enzyme-functionalized dual-peak LPFG has the advantage of direct inscription of highly sensitive grating structures in thin-cladding fibre without etching, and most significantly, its sensitivity improvement of approximately one order of magnitude higher than previously reported LPFG and excessively tilted fibre grating (Ex-TFG) for glucose detection.

Small-period long-period fiber grating with improved refractive index sensitivity and dual-parameter sensing ability.

We UV inscribe and characterize a long-period fiber grating with a period of 25 µm. A series of polarization-dependent dual-peak pairs can be seen in the transmission spectrum, even though only the symmetrical refractive index modification is introduced. The fabricated grating exhibits a lower temperature sensitivity compared with standard long-period gratings and an enhanced refractive index sensitivity of ∼312.5 nm/RIU averaged from 1.315 to 1.395, which is more than four-fold higher than standard long-period gratings in this range. The full width at half-maximum of the fabricated grating is only about 0.6 nm, allowing for high-resolution sensing. Moreover, the grating period is so small that the attenuation dip corresponding to a high-order Bragg resonance can also be seen, which can act as a monitor of the unwanted perturbation to realize dual-parameter sensing.

DWARF14 is a non-canonical hormone receptor for strigolactone.

Classical hormone receptors reversibly and non-covalently bind active hormone molecules, which are generated by biosynthetic enzymes, to trigger signal transduction. The α/ß hydrolase DWARF14 (D14), which hydrolyses the plant branching hormone strigolactone and interacts with the F-box protein D3/MAX2, is probably involved in strigolactone detection. However, the active form of strigolactone has yet to be identified and it is unclear which protein directly binds the active form of strigolactone, and in which manner, to act as the genuine strigolactone receptor. Here we report the crystal structure of the strigolactone-induced AtD14-D3-ASK1 complex, reveal that Arabidopsis thaliana (At)D14 undergoes an open-to-closed state transition to trigger strigolactone signalling, and demonstrate that strigolactone is hydrolysed into a covalently linked intermediate molecule (CLIM) to initiate a conformational change of AtD14 to facilitate interaction with D3. Notably, analyses of a highly branched Arabidopsis mutant d14-5 show that the AtD14(G158E) mutant maintains enzyme activity to hydrolyse strigolactone, but fails to efficiently interact with D3/MAX2 and loses the ability to act as a receptor that triggers strigolactone signalling in planta. These findings uncover a mechanism underlying the allosteric activation of AtD14 by strigolactone hydrolysis into CLIM, and define AtD14 as a non-canonical hormone receptor with dual functions to generate and sense the active form of strigolactone.

Theoretical and experimental analysis of excessively tilted fiber gratings.

We have theoretically and experimentally investigated the dual-peak feature of tilted fiber gratings with excessively tilted structure (named as Ex-TFGs). We have explained the dual-peak feature by solving eigenvalue equations for TM0m and TE0m of a circular waveguide, in which the TE (transverse electric) and TM (transverse magnetic) core modes are coupled into TE and TM cladding modes, respectively. Meanwhile, in the experiment, we have verified that one of the dual peaks at the shorter wavelength is due to the TM mode coupling whereas the other one at the longer wavelength arises from TE mode coupling when a linearly polarized light launched into the Ex-TFG. We have also investigated the peak separation of TE and TM cladding mode for different surrounding medium refractive indexes (SRI), revealed that the dual peaks separation is decreasing as increasing of SRI, which agrees very well with the theoretical analysis results.