Synergistic effect of two bacterial strains promoting anaerobic digestion of rice straw to produce methane.

A large amount of agricultural waste causes global environmental pollution. Biogas production by microbial pretreatment is an important way to utilize agricultural waste resources. In this study, Sporocytophaga CG-1 (A, cellulolytic strain) was co-cultured with Bacillus clausii HP-1 (B, non-cellulolytic strain) to analyze the effect of pretreatment of rice straw on methanogenic capacity of anaerobic digestion (AD). The results showed that weight loss rate of filter paper of co-culture combination is 53.38%, which is 29.37% higher than that of A. The synergistic effect of B on A can promote its degradation of cellulose. The cumulative methane production rate of the co-culture combination was the highest (93.04 mL/g VS substrate), which was significantly higher than that of A, B and the control group (82.38, 67.28 and 67.70 mL/g VS substrate). Auxiliary bacteria can improve cellulose degradation rate by promoting secondary product metabolism. These results provide data support for the application of co-culture strategies in the field of anaerobic digestion practices.

Temperature-dependent UV-Vis dielectric functions of BaTiO3 across ferroelectric-paraelectric phase transition.

Ferroelectric BaTiO3 with an electric-field-switchable spontaneous polarization has attracted wide attention in photovoltaic applications due to its efficient charge separation for photoexcitation. The evolution of its optical properties with rising temperature especially across the ferroelectric-paraelectric phase transition is critical to peer into the fundamental photoexcitation process. Herein, by combining spectroscopic ellipsometry measurements with first-principles calculations, we obtain the UV-Vis dielectric functions of perovskite BaTiO3 at temperatures varying from 300 to 873 K and provide the atomistic insights into the temperature-driven ferroelectric-paraelectric (tetragonal-cubic) structural evolution. The main adsorption peak in dielectric function of BaTiO3 is reduced by 20.6% in magnitude and redshifted as temperature increases. The Urbach tail shows an unconventional temperature-dependent behavior due to the microcrystalline disorder across the ferroelectric-paraelectric phase transition and the decreased surface roughness at around 405 K. From ab initio molecular dynamics simulations, the redshifted dielectric function of ferroelectric BaTiO3 coincidences with the reduction of the spontaneous polarization at elevated temperature. Moreover, a positive (negative) external electric field is applied which can modulate the dielectric function of ferroelectric BaTiO3 blueshift (redshift) with a larger (smaller) spontaneous polarization since it drives the ferroelectric further away from (closer to) the paraelectric structure. This work sheds light on the temperature-dependent optical properties of BaTiO3 and provides data support for advancing its ferroelectric photovoltaic applications.

Effects of temperature and charged vacancies on electronic and optical properties of ß-Ga2O3 after radiation damage.

ß-Ga2O3 as an ultra-wide bandgap material is widely used in space missions and nuclear reactor environments. It is well established that the physical properties of ß-Ga2O3 would be affected by radiation damage and temperature in such application scenarios. Defects are inevitably created in ß-Ga2O3 upon irradiation and their dynamic evolution is positively correlated with the thermal motion of atoms as temperature increases. This work utilizes first-principles calculations to investigate how temperature influences the electronic and optical properties of ß-Ga2O3 after radiation damage. It finds that the effect of p-type defects caused by Ga vacancies on optical absorption diminishes as temperature increases. The high temperature amplifies the effect of oxygen vacancies to ß-Ga2O3, however, making n-type defects more pronounced and accompanied by an increase in the absorption peak in the visible band. The self-compensation effect varies when ß-Ga2O3 contains both Ga vacancies and O vacancies at different temperatures. Moreover, in the case of Ga3- (O2+) vacancies, the main characters of p(n)-type defects caused by uncharged Ga0 (O0) vacancies disappear. This work aims to understand the evolution of physical properties of ß-Ga2O3 under irradiation especially at high temperatures, and help analyze the damage mechanism in ß-Ga2O3-based devices.

First-principles study of thermal transport properties in ferroelectric HfO2 and related fluorite-structure ferroelectrics.

The discovery of ferroelectricity in the fluorite-structure HfO2 has attracted much interest in various applications including electro-optic devices and nonvolatile memories. Doping and alloying not only induce ferroelectricity in HfO2, but also significantly impact the thermal conduction which plays an essential role in the heat dissipation and thermal stability of ferroelectric devices. To understand and regulate the heat transfer in ferroelectric HfO2, it is crucial to investigate the thermal conduction properties of related fluorite-structure ferroelectrics so as to establish the structure-property relationship. In this work, using first-principles calculations, we investigate the thermal transport in twelve fluorite-structure ferroelectrics. We find an overall satisfactory agreement between the calculated thermal conductivities and those predicted by the simple theory of Slack. Among the family of fluorite-structure ferroelectrics, the transition-metal oxides HfO2 and ZrO2 have the highest thermal conductivities due to the strong interatomic bonding. We demonstrate that the spontaneous polarization, a feature specific to ferroelectrics, is positively correlated with the thermal conductivity, namely, the larger the spontaneous polarization, the larger the thermal conductivity. This is of chemical origin, namely, both the spontaneous polarization and the thermal conductivity are positively correlated to the "ionicity" of the ferroelectrics. We further find that the thermal conductivity is several times lower in the ferroelectric solid solution Hf1-xZrxO2 than in its pure counterparts, especially in the thin films where the finite size effect further suppresses thermal conduction. Our findings suggest the spontaneous polarization as a specific criterion for identifying ferroelectrics with desired thermal conductivities, which may promote the design and application of ferroelectrics.

A general LC-MS-based RNA sequencing method for direct analysis of multiple-base modifications in RNA mixtures.

A complete understanding of the structural and functional potential of RNA requires understanding of chemical modifications and non-canonical bases; this in turn requires advances in current sequencing methods to be able to sequence not only canonical ribonucleotides, but at the same time directly sequence these non-standard moieties. Here, we present the first direct and modification type-independent RNA sequencing method via introduction of a 2-dimensional hydrophobic end-labeling strategy into traditional mass spectrometry-based sequencing (2D HELS MS Seq) to allow de novo sequencing of RNA mixtures and enhance sample usage efficiency. Our method can directly read out the complete sequence, while identifying, locating, and quantifying base modifications accurately in both single and mixed RNA samples containing multiple different modifications at single-base resolution. Our method can also quantify stoichiometry/percentage of modified RNA versus its canonical counterpart RNA, simulating a real biological sample where modifications exist but may not be 100% at a particular site in the RNA. This method is a critical step towards fully sequencing real complex cellular RNA samples of any type and containing any modification type and can also be used in the quality control of modified therapeutic RNAs.

Associations of genetic polymorphisms in CTLA-4 and IL-18 with chronic liver diseases: Evidence from a meta-analysis.

BACKGROUND: The aim of this meta-analysis was to explore associations between polymorphisms in CTLA-4/IL-18 and chronic liver diseases by combing the results of all relevant studies. METHODS: Eligible studies were searched from Pubmed, Embase, Web of Science and Cochrane library. We used Review Manager to combine the results of eligible studies. RESULTS: Sixty-seven studies were included in this meta-analysis. Combined results revealed that CTLA-4 rs231775 (dominant, recessive and allele comparisons), IL-18 rs1946518 (dominant, recessive and allele comparisons) and IL-18 rs187238 (dominant, over-dominant and allele comparisons) polymorphisms were all significantly associated with chronic liver diseases in the overall population. We also obtained similar positive results for rs231775, rs5742909, rs3087243, rs1946518 and rs187238 polymorphisms in subgroup analyses by ethnicity and type of disease. CONCLUSIONS: This meta-analysis demonstrated that CTLA-4 rs231775, CTLA-4 rs5742909, CTLA-4 rs3087243, IL-18 rs1946518 and IL-18 rs187238 polymorphisms may confer susceptibility to certain types of chronic liver diseases.

Adsorption of hexavalent chromium using modified walnut shell from solution.

Modified walnut shell (MWS) was obtained using diethylenetriamine through a grafting reaction and its adsorption capacity toward Cr(VI) was enhanced. The adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and elemental analysis and the results showed that the modification was effective. To optimize experimental conditions, the effect of temperature, solution pH, salinity, contact time, and Cr(VI) concentration on adsorption quantity were performed in batch mode. It showed that the adsorption ability for Cr(VI) onto MWH can reach 50.1 mg·g-1 at 303 K with solution pH 3. Both the solution pH and salinity had a great impact on the adsorption capacity. The Langmuir model can predict the equilibrium process while the pseudo-second-order model can describe the kinetic process. The Yan model can be used to predict the column process. Additionally, there was also some regeneration ability for Cr-loaded MWH. Consequently, MWS is effective for removing Cr(VI) from solution.

Structural insights into RNA duplexes with multiple 2΄-5΄-linkages.

2΄-5΄-linked RNAs play important roles in many biological systems. In addition, the mixture of 2΄-5΄ and 3΄-5΄ phosphodiester bonds have emerged as a plausible structural element in prebiotic RNAs. Toward our mechanistic studies of RNA folding and structures with heterogeneous backbones, we recently reported two crystal structures of a decamer RNA duplex containing two and six 2΄-5΄-linkages, showing how RNA duplexes adjust the structures to accommodate these non-canonical linkages (Proc. Natl. Acad. Sci. USA, 2014, 111, 3050-3055). Herein, we present two additional high-resolution crystal structures of the same RNA duplex containing four and eight 2΄-5΄-linkages at different positions, providing new insights into the effects of these modifications and a dynamic view of RNA structure changes with increased numbers of 2΄-5΄-linkages in the same duplex. Our results show that the local structural perturbations caused by 2΄-5΄ linkages can be distributed to nearly all the nucleotides with big ranges of changes in different geometry parameters. In addition, hydration pattern and solvation energy analysis indicate less favorable solvent interactions of 2΄-5΄-linkages comparing to the native 3΄-5΄-linkages. This study not only promotes our understanding of RNA backbone flexibility, but also provides a knowledge base for studying the biochemical and prebiotic significance of RNA 2΄-5΄-linkages.

Seasonal association between ambient ozone and mortality in Zhengzhou, China.

Different seasonal health effects of ambient ozone (O3) have been reported in previous studies. This might be due to inappropriate adjustment of temperature in different seasons. We used daily data on non-accidental mortality and ambient air pollution in Zhengzhou from January 19, 2013 to June 30, 2015. Season-stratified analyses using generalized additive models were conducted to evaluate the seasonal associations with adjustment of temperature with different lagged days (lag0-1 for warm season, lag0-14 for cold season). We recorded a total of 70,443 non-accidental deaths in Zhengzhou during the study period. Significant associations were observed between ambient O3 and mortality in cold season. Every 10-µg/m3 increment of 24-h O3 of 1-day lagged time was associated with a 1.38% (95% CI 0.60, 2.16%) increase in all cause mortality, 1.35% (95% CI 0.41, 2.30%) increase in cardiovascular mortality, and 1.78% (95% CI 0.43, 3.14%) increase in respiratory mortality. Similar associations were observed when using daily 1- and 8-h maximum concentrations of O3. No significant association was found during warm season. This study suggests a more pronounced ozone-mortality association in cold season in Zhengzhou, and we suggest that different lagged temperatures should be considered when examining the seasonal health effects of ambient ozone.

Fast and accurate nonenzymatic copying of an RNA-like synthetic genetic polymer.

Recent advances suggest that it may be possible to construct simple artificial cells from two subsystems: a self-replicating cell membrane and a self-replicating genetic polymer. Although multiple pathways for the growth and division of model protocell membranes have been characterized, no self-replicating genetic material is yet available. Nonenzymatic template-directed synthesis of RNA with activated ribonucleotide monomers has led to the copying of short RNA templates; however, these reactions are generally slow (taking days to weeks) and highly error prone. N3'-P5'-linked phosphoramidate DNA (3'-NP-DNA) is similar to RNA in its overall duplex structure, and is attractive as an alternative to RNA because the high reactivity of its corresponding monomers allows rapid and efficient copying of all four nucleobases on homopolymeric RNA and DNA templates. Here we show that both homopolymeric and mixed-sequence 3'-NP-DNA templates can be copied into complementary 3'-NP-DNA sequences. G:T and A:C wobble pairing leads to a high error rate, but the modified nucleoside 2-thiothymidine suppresses wobble pairing. We show that the 2-thiothymidine modification increases both polymerization rate and fidelity in the copying of a 3'-NP-DNA template into a complementary strand of 3'-NP-DNA. Our results suggest that 3'-NP-DNA has the potential to serve as the genetic material of artificial biological systems.

Bidirectional Direct Sequencing of Noncanonical RNA by Two-Dimensional Analysis of Mass Chromatograms.

Mass spectrometry (MS) is a powerful technique for characterizing noncanonical nucleobases and other chemical modifications in small RNAs, yielding rich chemical information that is complementary to high-throughput indirect sequencing. However, mass spectra are often prohibitively complex when fragment ions are analyzed following either solution phase hydrolysis or gas phase fragmentation. For all but the simplest cases, ions arising from multiple fragmentation events, alternative fragmentation pathways, and diverse salt adducts frequently obscure desired single-cut fragment ions. Here we show that it is possible to take advantage of predictable regularities in liquid chromatographic (LC) separation of optimized RNA digests to greatly simplify the interpretation of complex MS data. A two-dimensional analysis of extracted compound chromatograms permits straightforward and robust de novo sequencing, using a novel Monte Carlo algorithm that automatically generates bidirectional paired-end reads, pinpointing the position of modified nucleotides in a sequence. We demonstrate that these advances permit routine LC-MS sequencing of RNAs containing noncanonical nucleotides, and we furthermore examine the applicability of this approach to the study of oligonucleotides containing artificial modifications as well as those commonly observed in post-transcriptionally modified RNAs.

[Preliminary Investigation of the Amount, the Molecular Weight and the Activity of Polysaccharides from Chaenomeles Speciosa Fruits in Ethanol Fractional Precipitation].

Chaenomeles speciosa fruits were extracted using water. The extracts were precipitated with 20%~95% (φ) ethanol, respectively. The amount of total polysaccharide was measured with phenol-sulfuric acid method. A method using high-performance size-exclusion chromatography (HPSEC) equipped with multiangle laser-light-scattering photometry (MALLS) and differential refractometry (RI) was presented for determining the molecular weight and molecular weigh distribution. RAW264.7 macrophage were cultured and stimulated with the polysaccharides in vitro and the production of nitric oxide in the cells was determined by the Griess assay. The aim of the study is to determine the amount and the molecular weight of the polysaccharides from Chaenomeles speciosa fruits, and preliminary investigate the immunomodulatory activity, The study provided the basis datas for the further research of Chaenomeles speciosa fruits. , and provided a simple and system method for the research of natural polysaccharide. The ethanol fractional precipitation showed that the order of total polysaccharide content was 95%>80%>40% ≥60%>20%. The results indicated that most polysaccharide from Chaenomeles speciosa fruits might be precipitated when ethanol concentration was up to 95% (T) and the crude polysaccharide purity had risen from 35. 1% to 45. 0% when the concentration of ethanol increased from 20% to 95%. HPSEC-MALLS-RI system showed that all the polysaccharide samples had the similar compositions. They appeared three chromatographic peaks and the retention time were not apparently different. The Mw were 6. 570 X 10(4) g . mol-1 and 1. 393 X 10(4) g . mol-1 respectively, and one less than 10 000 which was failure to obtain accurate values. The molecular weight of the first two polysaccharide distribution index(Mw/Mn)were 1. 336 and 1. 639 respectively. The polysaccharide samples had not exhibited immunomodulatory activity assessed on the basis of nitric oxide production by RAW264. 7 macrophage cells in the experiment.

Risk factors associated with failed sonographically guided saline hydrostatic intussusception reduction in children.

OBJECTIVES: The aim of this study was to explore the risk factors associated with failed sonographically guided saline hydrostatic intussusception reduction in children. METHODS: We retrospectively reviewed the medical records and sonograms of 288 cases of intussusception over a 3-year period. Logistic regression was used for the analysis of the clinical data (sex, age, duration of symptoms, and presence or absence of emesis or bloody stool) and sonographic features (initial location and intussusception length, presence or absence of free peritoneal fluid, and trapped fluid in the intussusception). RESULTS: The sex, age, and duration of symptoms showed no significant impact on the hydrostatic reducibility. The success rate became significantly lower for the intussusception cases with the presence of bloody stool, free peritoneal fluid, and trapped fluid in the intussusception (P < .05). The success rate was also lower when the intussusceptions were located in the left side of the abdomen (P < .05). For the above risk factors, the odds ratios from multivariate logistic regression analysis were 174.68 for initial intussusception location in the descending colon/rectum, 36.06 for the presence of peritoneal fluid, 13.22 for trapped fluid in the intussusception, and 9.27 for the presence of bloody stool. CONCLUSIONS: An initial intussusception location in the descending colon/rectum, the presence of peritoneal fluid, trapped fluid in the intussusception, and bloody stool are the most important risk factors for failure of sonographically guided saline hydrostatic intussusception reduction.

Electron Spin Broken-Symmetry of Fe-Co Diatomic Pairs to Promote Kinetics of Bifunctional Oxygen Electrocatalysis for Zinc-Air Batteries.

Designing bifunctional catalysts to reduce the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) reaction barriers while accelerating the reaction kinetics is perceived to be a promising strategy to improve the performance of Zinc-air batteries. Unsymmetric configuration in single-atom catalysts has attracted attention due to its unique advantages in regulating electron orbitals. In this work, a seesaw effect in unsymmetric Fe-Co bimetallic monoatomic configurations is proposed, which can effectively improve the OER/ORR bifunctional activity of the catalyst. Compared with the symmetrical model of Fe-Co, a strong charge polarization between Co and Fe atoms in the unsymmetric model is detected, in whom the spin-down electrons around Co atoms are much higher than those spin-up electrons. The seesaw effect occurred between Co atoms and Fe atoms, resulting in a negative shift of the d-band center, which means that the adsorption of oxygen intermediates is weakened and more conducive to their dissociation. The optimized reaction kinetics of the catalyst leads to excellent performance in ZABs, with a peak power density of 215 mW cm-2 and stable cycling for >1300 h and >4000 cycles. Flexible Zinc-air batteries have also gained excellent performance to demonstrate their potential in the field of flexible wearables.

Synthesis of N3'-P5'-linked phosphoramidate DNA by nonenzymatic template-directed primer extension.

A fast and accurate pathway for nonenzymatic RNA replication would simplify models for the emergence of the RNA world from the prebiotic chemistry of the early earth. However, numerous difficulties stand in the way of an experimental demonstration of effective nonenzymatic RNA replication. To gain insight into the necessary properties of potentially self-replicating informational polymers, we have studied several model systems based on amino-sugar nucleotides. Here we describe the synthesis of N3'-P5'-linked phosphoramidate DNA (3'-NP-DNA) by the template-directed polymerization of activated 3'-amino-2',3'-dideoxyribonucleotides. 3'-NP-DNA is an interesting model because of its very RNA-like A-type duplex conformation and because activated 3'-amino-2',3'-dideoxyribonucleotides are much more reactive than the corresponding activated ribonucleotides. In contrast to our previous studies with 2'-amino-2',3'-dideoxyribonucleotides (for which G and C but not A and T exhibit efficient template copying), we have found that all four canonical 3'-amino-2',3'-dideoxyribonucleotides (G, C, A, and T) polymerize efficiently on RNA templates. RNA templates are generally superior to DNA templates, and oligo-ribo-T templates are superior to oligo-ribo-U templates, which are the least efficient of the RNA homopolymer templates. We have also found that activation of 3'-aminonucleotides with 2-methylimidazole results in a ca. 10-fold higher polymerization rate relative to activation with imidazole, an observation that parallels earlier findings with ribonucleotides. We discuss the implications of our experiments for the possibility of self-replication in the 3'-NP-DNA and RNA systems.

Adsorption of chloro-anilines from solution by modified peanut husk in fixed-bed column.

Natural peanut husk (NPH) modified with hexadecyl trimethyl ammonium bromide (CTAB) was used as adsorbent to remove 2,5-dimethoxy-4-chloroaniline (DMCH) from solution in a fixed-bed column. Fourier transform infrared spectroscopy analysis and X-ray fluorescence of NPH and modified peanut husk (MPH) showed that CTAB had been introduced onto the surface of NPH. The effects of flow rate and bed depth on breakthrough curves were studied. The Thomas model and the Yan model were selected to fit the column adsorption data and the results showed that the Yan model was better at predicting the breakthrough curves. The adsorption quantity was up to 6.46 mg/g according to the Yan model. The bed depth service time model was used to calculate the critical bed depth from experimental data and it was directly related to flow rate. As a low-cost adsorbent, MPH is promising for the removal of DMCH from solution.

Ameliorative effects of pine nut peptide-zinc chelate (Korean pine) on a mouse model of Alzheimer's disease.

In this study, 50 SD adult male mice were used to create an Alzheimer's disease model. The mice's learning and memory abilities were evaluated using an eight-arm radial maze experiment, and changes in body weight and food intake were noted. This helped to better validate the improvement of Alzheimer's disease caused by pine nut peptide-zinc chelate (Korean pine). For a more thorough investigation, mice's brains were dissected, Endogenous mercaptan antioxidants (enzymes), which are markers of brain tissue, were assessed, and mouse gut flora was analyzed. The findings demonstrated that pine nut peptide-zinc chelate (Korean pine) can improve learning and memory, stop brain aging and damage, and control gut flora in mice. It may exert its effects by ameliorating decreased AChE levels and increased ChAT levels in the central cholinergic system, endogenous thiol antioxidants (enzymes) in the cerebral cortex, and by controlling the bacterial flora in the gut.

Preparation and characterization of soluble dietary fiber from tiger nut residues, showing enhanced antioxidant activity and metal-ion-binding properties.

To improve the utilization of soluble dietary fiber (SDF) from tiger nut residues, the response surface methodology was used to optimize the conditions of superfine grinding to produce SDF with antioxidant and metal-ion-binding properties. The yield was increased (30.56%) and the average particle diameter of SDF was decreased (D50: 32.80 µm) under the optimal conditions (a proportion of grinding medium of 100%, a feeding mass of 0.90 kg, a grinding time of 20 min, and a moisture content of 8.00%). In addition, superfine grinding substantially modified the surface morphology and increased the SDF content and the proportion of monosaccharides by decreasing the molecular weight. Moreover, superfine grinding remarkably enhanced the in vitro antioxidant activities (ABTS+, DPPH, and ·OH) of the SDF, which also exhibited favorable metal-ion-binding properties (Ca2+, Zn2+, and Co2+). These results suggest that superfine grinding can be used as a technique to modify dietary fiber to manufacture functional SDF.

Activated ribonucleotides undergo a sugar pucker switch upon binding to a single-stranded RNA template.

Template-directed polymerization of chemically activated ribonucleotide monomers, such as nucleotide 5'-phosphorimidazolides, has been studied as a model for nonenzymatic RNA replication during the origin of life. Kinetic studies of the polymerization of various nucleotide monomers on oligonucleotide templates have suggested that the A-form (C3'-endo sugar pucker) conformation is optimal for both monomers and templates for efficient copying. However, RNA monomers are predominantly in the C2'-endo conformation when free in solution, except for cytidine, which is approximately equally distributed between the C2'-endo and C3'-endo conformations. We hypothesized that ribonucleotides undergo a switch in sugar pucker upon binding to an A-type template and that this conformational switch allows or enhances subsequent polymerization. We used transferred nuclear Overhauser effect spectroscopy (TrNOESY), which can be used for specific detection of the bound conformation of small-molecule ligands with relatively weak affinity to receptors, to study the interactions between nucleotide 5'-phosphorimidazolides and single-stranded oligonucleotide templates. We found that the sugar pucker of activated ribonucleotides switches from C2'-endo in the free state to C3'-endo upon binding to an RNA template. This switch occurs only on RNA and not on DNA templates. Furthermore, activated 2'-deoxyribonucleotides maintain a C2'-endo sugar pucker in both the free and template-bound states. Our results provide a structural explanation for the observations that activated ribonucleotides are superior to activated deoxyribonucleotides and that RNA templates are superior to DNA templates in template-directed nonenzymatic primer-extension reactions.