Search

AIMS The purpose of this study is to examine the safety and efficacy of eltrombopag as first-line treatment for thrombocytopenia among paediatric patients after haematopoietic stem cell transplantation (HSCT). METHODS Forty-three childhood patients with thrombocytopenia after HSCT who received eltrombopag were retrospectively analysed. RESULT Eltrombopag was began at the median of 27 days after HSCT and lasted for 24 days. Thirty-five children responded to eltrombopag therapy, and the cumulative platelet recovery rate was 88.9%. The cumulative incidence of platelet recovery was lower (83.9 vs 100%; P = .035) in patients with decreased numbers of megakaryocytes before starting eltrombopag than in those with normal. Factors associated with a significantly elevated response to eltrobopag from univariate analysis were donor type. Results from the multiple regression analysis found that weight (hazard ratio [HR] = 0.7, 95% confidence interval [CI] 0.5-0.9, P = .022), platelet engraftment time (HR = 1.0, 95%CI 1.0-1.0, P = .012) and bone marrow megakaryocytes (HR = 8.0, 95%CI 1.5-43.3, P = .016) before starting eltrombopag were the independent risk factors. Based on Youden's index algorithm in the receiver-operating characteristic curve, the optimal cut-off value of the maintenance dose of eltrombopag in predicting nonresponders was 4 mg/kg. The area under the receiver-operating characteristic curve was 0.923 with sensitivity of 97.8%, specificity of 87.9%, positive predictive value of 72.3%, and negative predictive value of 92%. None of the paediatric patients stopped using eltrombopag due to side effect or intolerability. CONCLUSION Eltrombopag is effective and safe in paediatric patients with thrombocytopenia after HSCT. The number of megakaryocytes in bone marrow before eltrombopag treatment may serve as a predictor of the response to eltrombopag. We recommend that the maintenance dose of eltrombopag should not exceed 4 mg/kg/d.

Titanium dioxide (TiO2) is a widely used photocatalyst that can oxidize motor vehicle exhaust, for example, carbon monoxide (CO), nitrogen oxides (NOx), hydrocarbons, and sulfur dioxide, under the irradiation of sunlight. It has been reported that nano-scale TiO2particles can be effectively used to modify the concrete-asphalt pavement, and make it as a photocatalytic pavement. However, the pure TiO2additive limits its absorption spectrum to the ultraviolet region, which only occupies a small portion of sunlight irradiance. To increase the utilization of the full spectrum of sunlight, it has been demonstrated that doping TiO2with substances such as Carbon (C), Nitrogen (N), or metal can reduce the band-gap and extend the threshold of the absorption spectrum to the visible light region. Therefore, doped-TiO2has a better photocatalytic performance under sunlight irradiation. This paper conducted computational simulation of the kinetics of photocatalytic pavement to quantify the efficiency of doped-TiO2embedded pavement in reducing exhaust gas from motor vehicles. A three-dimensional model is developed on a section of local road with doped-TiO2embedded pavement. The effects of doped-TiO2concentration, daylight conditions, and traffic flow conditions on the removal of NOxand CO were studied. The results indicate that the pavement with doped-TiO2coating is effective to remove CO and NOxunder different traffic density and daylight intensity conditions. Compared with UV activated TiO2, visible-light-activated doped-TiO2features significantly higher removal efficiency of poisonous exhaustive gas including NOxand CO.

This work presented hydrodynamic performance of pilot-scale pulsed sieve-plate column (PSPC) and pulsed disc-and-doughnut column (PDDC) in different operation modes for the uranyl nitrate/30% (v/v)...

This paper describes a systematic method with high accuracy and efficiency to scientifically analyse the long-term stability and deformation behaviour of an anhydrite mine-out located in Anhui, South China and evaluate the feasibility of this mine-out as an underground crude oil storage space. Applying the particle swarm optimization algorithm, the parameters of Burgers creep model of anhydrite rock were obtained based on the uniaxial compressive creep test. Considering the results of numerical simulation, element safety factor (Esf) based on the Mohr’s strength theory was introduced and modified to quantificationally evaluate the long-term stability of cavern group. Combining field monitoring, the long-term deformation behaviour of the mine-out was analysed. The results show that the mine-out has good long-term stability and non-deformability. After 100 years of natural deformation, the vertical convergence deformation of the cavern is less than 500 mm, while lateral convergence deformation is less than 450 mm. The ground settlement is not more than 234 mm. The maximum loss rate of the space volume is no more than 5.38%, which is 4.75% under the condition of crude oil storage with 1.0 MPa internal pressure. Therefore, the mine-out has the potential to serve as an underground crude oil storage space.

A novel roofing system was designed to actively tailor solar heat gains in buildings, potentially reducing overall space heating and cooling energy needs and costs. The multifunctional films containing thermochromic materials and/or nano-TiO2 particles are featured with high solar reflectance throughout the entire solar spectrum and potential self-cleaning capacity. In this study, the novel roof system was designed by integrating multifunctional films with traditional roofing materials (aluminum, wood, plastics, and asphalt concrete). The optical characterization found that the solar reflectance value in the wavelength region of 300–1800 nm could reach up to 24–35% for individual multifunctional film whereas the value was 40%, 48%, 39%, and 40% for the roofing systems based on aluminum, wood, plastics, and asphalt concrete, respectively. The effectiveness of multifunctional films in modulating thermal performance of innovative roofing systems was experimentally examined. The experimental results demonstrated that the film containing both thermochromic materials and nano-TiO2 particles produced a drop in interior surface temperature as high as 3.5 °C for roofing system based on asphalt concrete and 9–10 °C for roofing system based on plastics. The proposed innovative roof systems have the potential for the reduction of heat absorption and cooling loads as well as mitigation of heat island effects.

This paper describes an innovative machine learning (ML) model to predict the performance of different metal oxide photocatalysts on a wide range of contaminants. The molecular structures of metal oxide photocatalysts are encoded with a crystal graph convolution neural network (CGCNN). The structure of organic compounds is encoded via digital molecular fingerprints (MF). The encoded features of the photocatalysts and contaminants are input to an artificial neural network (ANN), named as CGCNN-MF-ANN model. The CGCNN-MF-ANN model has achieved a very good prediction of the photocatalytic degradation rate constants by different photocatalysts over a wide range of organic contaminants. The effects of the data training strategy on the ML model performance are compared. The effects of different factors on photocatalytic degradation performance are further evaluated by feature importance analyses. Examples are illustrated on the use of this novel ML model for optimal photocatalyst selection and for assessing other types of photocatalysts for different environmental applications.

Predicting the behaviors of thermoelectric material, such as the Seebeck coefficient, using first-principle material properties will accelerate material design and selection to optimize the performance of thermoelectric generator. This paper presents an analytic framework for the Seebeck coefficient. Particularly, it elucidates the important contribution of chemical potential to the overall Seebeck coefficient. This factor, however, is often neglected when Seebeck coefficient is defined based on only electrostatic potential or when methods based on the Boltzmann transportation equation is used to derive the expression of the Seebeck coefficient. (The diffusion component due to chemical potential gradient is generally ignored.) In this paper, methods based on local equilibrium assumption and Fermi–Dirac distribution are utilized to derive the expressions for the Seebeck coefficients using the first-principle parameters. The analytic expression of both the total Seebeck coefficient and the contribution from chemical potential component is derived, which is solved using numerical methods. A case study on a popular thermoelectric material bismuth telluride (both n-type and p-type) is conducted based on the derived expressions. Results of numerical calculations prove that chemical potential contributes significantly to the total Seebeck coefficient of bismuth telluride (76% for n-type and 88% for p-type materials, respectively, at room temperature if the materials are doped with shallow energy level impurities) when working under optimal Seebeck coefficient conditions.

&beta, casein is a primary protein in milk, and its variants have been associated with changes in the protein content of bovine milk. However, there has been little research focused on the effects of &beta, casein variants on milk metabolites. In the present study, dairy cows producing milk with &beta, casein variant A1/A1 (A1), A2/A2 (A2), and their heterozygote A1/A2 (A12) were screened by a high-resolution melting method. Individual milk samples were then collected from each of the cows, and the milk metabolites were separated and analyzed using nuclear magnetic resonance spectroscopy- and liquid-chromatography mass spectrometry-based metabolomics techniques. Differences in metabolites among the variant groups were evaluated by multivariate statistical analysis. The relative abundances of methionine, proline, and &alpha, lactose were the highest in &beta, casein variant A2 milk, whereas choline, glycine, citric acid, and cyclic adenosine monophosphate (cAMP) showed the highest abundances in variant A1 milk. Metabolic pathways analysis indicated that the differential metabolites between variants A1 and A2 were involved in pantothenate and coenzyme A biosynthesis, butanoate metabolism, and valine, leucine, and isoleucine biosynthesis. Our results reveal the differences in milk metabolites among the &beta, casein variants A1, A2, and the heterozygote. These findings, thus, provide novel insights into the effects of &beta, casein variants on milk metabolites, facilitating further research into the mechanism of the biosynthesis of milk components in the mammary gland and the potential physiological function of milk associated with &beta, casein variants.

A three-dimensional (3D) computational fluid dynamics (CFD) simulation of liquid–liquid two-phase flow is performed on a pilot-plant scale annular pulsed disc and doughnut column (APDDC). T...

Thermochromic film is capable of modulating optical properties in response to environmental temperature. It has the potential to control solar heat gains in buildings and therefore to reduce energy consumptions. This study aims at investigating optical behaviors of thermochromic film using optical simulation. Thermochromic film is designed by incorporating thermochromic powders into polyvinyl chloride (PVC) matrix. The optical constants of both PVC film and thermochromic pigment are determined based on a series of reflectance and transmission measurement. The influence of powder concentration, temperature, and particle depth on normalized scattering and absorption cross section, forward scattering ratio, and diffuse reflectance of thermochromic film was investigated using optical simulation. These studies can serve as a model for understanding the interaction of light with thermochromic powder embedded in polymer matrix and facilitate the computer-aided design of thermochromic film with high thermochromic efficiency.

This study aims to investigate the feasibility of self-healing concrete with fungi. Fusarium oxysporum, a filamentous fungi strain that is capable of producing biomineralization was selected in the study. The growth behaviors of Fusarium oxysporum under the influence of concrete environment were studied under controlled conditions. The metabolism behaviors of Fusarium oxysporum that affect its self-healing capabilities, such as forming spores and growing mycelium were investigated with macroscopic observations as well as microscopic analytic instruments. The results show that Fusarium oxysporum was able to germinate on the surface of concrete and engaged in rapid mycelium development. The alkaline environment has an influence on the growth of fungal mycelium by slowing their growth. However, under favorable conditions, Fusarium oxysporum mycelium covered a surface area of mortar 86 times the area of the original fungi inoculum after 96 h. Such fast growth of Fusarium oxysporum could contribute to high efficiency in healing cracks. Microscopic characterization by SEM and FTIR further confirmed the metabolism activities of fungi produce biominerals inductive to self-healing performance. The fungal mycelium demonstrated hydrophobic nature. Analyses indicated that compared with bacteria-based self-healing, Fusarium oxysporum can potentially significantly increase the healing efficiency. Depending upon the pH value, fungi based healing time is 11.3%, 15.1% and 79.6% of the healing time required with MICP. Besides, the water repellency of mycelium would reduce the water infiltration rate to 17.22% of that of regular concrete surface, a benefit unseen in bacteria induced MICP. Fungi induced self-healing is environmental friendly than MICP process since no toxic gases are released. Overall, this study demonstrated fungi mediated self-healing mechanism via crack filling and improvement of water tightness as a novel strategy to significantly improve the durability concrete.

The engineering properties of clayey soils, including fluid permeability, erosion resistance and cohesive strength, are quite different from those of non-cohesive soils. This is mainly due to their small platy particle shape and the surrounding diffuse double layer structure. By using the Atomic Force Microscopy (AFM), the surface topography and the interaction force between the silicon dioxide tip and the kaolinite/montmorillonite clay minerals have been measured in the 1.0 mM NaCl solution at neutral pH. From this, the surface potential of the clay minerals is determined by mathematical regression analyses using the DLVO model. The length/thickness ratio of kaolinite and montmorillonite particles measured ranges from 8.0 to 15.0. The surface potential and surface charge density vary with particles. The average surface potential of montmorillonite is −62.8 ± 10.6 mV, and the average surface potential of kaolinite is −40.9 ± 15.5 mV. The measured results help to understand the clay sediment interaction, and will be used to develop interparticle force model to simulate sediment transport during erosion process.

The purpose of this study was to investigate the rumen degradation characteristic of amaranth silage (Amaranthus hypochondriacus) including four kinds of growing stages (budding stage (BS), 50 d after planting (DAP), early flowering stage (ES), 58 DAP, peak flowering stage (PS), 70 DAP, heading stage (HS), 90 DAP). Four Holstein dairy cows with permanent ruminal cannulas were used as experimental animals. Nylon-bag method was used to assess the ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). The results showed that the concentration of DM in HS was significantly higher than other stages (p &lt, 0.05), whereas the contents of CP, were lower than in other stages (p &lt, 0.05). With the extension of the growing period, the DM effective degradability of amaranth silage decreased gradually, and the difference was significant (p &lt, 0.05). The ruminal CP degradation of 72 h was more than 80%, and compared with ES and HS, the degradation rate of BS and PS was significantly increased (p &lt, 0.05). Compared to BS, the effective degradability of CP was increased (p &lt, 0.05) in ES and HS. For ruminal NDF degradability, the effective degradability of HS was minimum, and it had a noticeable difference with BS and ES (p &lt, 0.05). Thus, the different quality of amaranth growth stage including chemical contents and rumen degradation should be taken into consideration when making amaranth silage. In the present study, the optimal growth stage of amaranth was from the peak flowering stage to heading stage for ensiling.

Gangliosides (GAs) and sulfatides (STs) are major acidic glycosphingolipids (GSLs) that are particularly abundant in the central nervous system and associated with substantial neurodegenerative diseases. In this study, we developed an improved approach for the comprehensive profiling of GAs and STs in rat brain tissues by adopting a pre-fractionation step before the LC-MS analysis. The pre-fractionation step allows the efficient enrichment of different types of acidic GSLs and the removal of high-abundance interferences, thereby greatly enhanced the detection sensitivity and accuracy of low-abundance acidic GSLs. By using this improved approach, a total of 340 acidic GSLs (from 281 compositions) were characterized in rat brain tissues, including 277 GAs (from 230 compositions) and 63 STs (from 51 compositions), among which 57 GAs and 14 STs were novel acidic GSLs that have not been reported previously. This study represented the most comprehensive profiling of acidic GSLs in rat brain tissues. The result of this study greatly enlarged our understanding of the structural diversity of natural acidic GSLs, and provided important chemical information for the exploration of biological function of acidic GSLs in the central nervous system.

Immobile string technology is often used to develop the production of multi-layer and thin low-permeability gas reservoirs. This type of reservoir is characterized by low productivities and high pressure drop rates. Simplified ground facilities and control choke technologies are often adopted to effectively reduce the investment. Because gas wells in low permeability gas reservoirs often have low productivities (for instance, the individual well production rates in the Sulige Gas Field range from only 3000 m3/d to 5000 m3/d), a large number of adopted down-hole sensors will result in gas fields that are unable to run properly. The water production data and the bottom pressure become difficult to measure. The casing pressure is controlled by both reservoir pressure and liquid accumulation. To predict liquid volume correctly, the superposed effects of the reservoir pressure and liquid accumulation should be stripped as a priority. Taking the dynamic reserve, production proration and production rate into consideration, we analyzed the casing pressures of dry gas wells. In addition, we quoted a parameter (the production rate in the unit casing pressure drop) to remove the influence of reservoir pressure drop and the output fluctuation “noise” on casing pressure. To strip out the effects of liquid accumulation, we discussed the casing pressure under different liquid accumulation rates. Through the above research, we created a method to calculate the annular liquid volume of an immobile string. This method applied to the Sulige Gas Field very well, and it can also be introduced to other similar gas reservoirs.

Titanium dioxide (TiO2) is a well-known photocatalyst in the applications of water contaminant treatment. Traditionally, the kinetics of photo-degradation rates are obtained from experiments, which consumes enormous labor and experimental investments. Here, a generalized predictive model was developed for prediction of the photo-degradation rate constants of organic contaminants in the presence of TiO2 nanoparticles and ultraviolet irradiation in aqueous solution. This model combines an artificial neural network (ANN) with a variety of factors that affect the photo-degradation performance, i.e., ultraviolet intensity, TiO2 dosage, organic contaminant type and initial concentration in water, and initial pH of the solution. The molecular fingerprints (MF) were used to interpret the organic contaminants as binary vectors, a format that is machine-readable in computational linguistics. A dataset of 446 data points for training and testing was collected from the literature. This predictive model shows a good accuracy with a root mean square error (RMSE) of 0.173.

In this paper, polymer nanocomposites made from epoxy and carbon nanotubes were developed and used as a sizing for basalt fibre. Full-scale experiment (two-factor and four-level combination) with quantitative analysis on the stability, wettability, conductivity, and morphology of liquid was applied to obtain the optimum formulation of sizing. The surface, electrical and mechanical properties of basalt fibre before and after sizing were studied. The results showed that nanocomposite sizing was deposited on the fibre surface during the fibre spinning process. The sizing gave significant increases on the electrical and tensile strength of basalt fibre, revealing the effectiveness of nanocomposites as a multi-functional material. The application of conducting sizing was a simple and effective way to enhance the technique value of insulating basalt fibre.

Alkanes are the important molecules in crude oil that have applications in different fields. In this project, molecular dynamics simulations have been applied to investigate the n-alkane-air and n-alkane-water interfaces. The surface tension, diffusion coefficients, order parameters, radial distribution function, density profiles and radius of gyration of alkanes in the bulk and on the interfaces with air/water were calculated and compared. It was found that with the n-alkane chain length increasing, the surface tension of the interface system increases. However, with the temperature increasing, the surface tension of the alkanes decreases. The alkanes on the interface can diffuse faster than in the bulk in both kinds of interface systems. While n-alkane diffusion rate in the bulk of interface systems is faster than in the pure alkane systems, the radius of gyration of alkanes in the bulk, on the interface and in the pure alkane systems is consistent. Decomposing the diffusion coefficients into the lateral direction and z-direction, the lateral diffusion rate of alkanes on the interface is about 2–10 times faster than in the z-direction in both kinds of interface systems. Although molecules prefer to pack randomly in the bulk, they are more orderly packed on the interface. The result can help to explain the interface effect in water/air-alkane interface systems. The project also demonstrates that using NAMD program and CHARMM forcfield can predict reasonable structure and properties of n-alkane-air/water systems.

To evaluate the effectiveness of the usage of anhydrite mine-out spaces for crude-oil storage, this study conducted a long-term experimental investigation on the interaction of anhydrite rock with crude oil and water with varying pressure using pressurized reactors designed in this work. The physical and mechanical properties of anhydrite-rock samples for different test periods were studied to evaluate the effect of crude oil and water on the anhydrite-rock properties and reveal the action mechanism. The crude-oil property was tested after the experiments were completed to evaluate the effect of anhydrite on the crude oil. The results demonstrated that under long-term contact with varying pressure, the crude oil did not affect the physical and mechanical properties of anhydrite, and the anhydrite did not affect the crude-oil properties. However, the dissolution and recrystallization effects of water on the anhydrite induced reduction in the strength and stiffness of the anhydrite rock to a certain extent. Thus, water can potentially reduce the stability of an anhydrite mine-out space, which should be focused on when an anhydrite mine-out space is used for underground crude-oil storage.

This work combined a Deep Neural Network (DNN) with molecular fingerprints (MF) to develop models to predict the OH radical rate constants of 593 organic contaminants. Molecular descriptors, most often used in establishing quantitative structural-activity relationships (QSARs), were not used here because of their complicated generation processes that rely on advanced physicochemical and computational knowledge. Instead, we only fed the most basic information of the contaminant structures, i.e., MF encoding the types of atoms and how they are connected, to DNN and DNN then developed predictive models automatically. Here, a dataset containing 457 contaminants and their OH rate constants was first used to develop predictive models by DNN-MF. The hence developed models showed comparable accuracy to the traditional QSARs. The root mean square error (RMSE) values of the test sets were 0.358-0.384. The length of 2048 bits for the MF and 3 hidden layers (each with 1024 neurons) were found to be the optimal parameters for DNN. The model containing additional 89 micorpollutants in the training set was then successfully applied to predict the OH rate constants of 17 organophosphorus flame retardants and 29 additional micropollutants, with comparable accuracy to the reported molecular descriptors-based QSARs.

Highway agencies frequently encounter problems caused by sulfate-induced heave in lime- and cement-treated subgrades. A thorough evaluation of sulfate-related risks for subgrades involves time-consuming laboratory tests. A real-time monitoring of the sulfate heaving phenomenon in the test section in the real field environment would provide a quick performance evaluation of sulfate soils treated with chemical additives. This would help transportation agencies in producing resilient pavements with low maintenance issues. This article presents an innovative hybrid sensor comprising a bender element and time domain reflectometry that can evaluate sulfate-related heave in real time. The new sensor was calibrated in the laboratory by studying the strength and stiffness behavior of three chemically treated high-sulfate soils. Following laboratory calibration, the sensor was embedded in lime-treated field sections, where the changes in moisture and stiffness were monitored simultaneously in real time. Field testing proved that the sensor was able to provide data to assess sulfate-induced heaving in the field. This article details the development of this sensor that can save millions of dollars for transportation agencies in the better stabilization design for sulfate soils.

Many Gram-negative bacteria use type 2 secretion systems (T2SSs) to secrete proteins involved in virulence and adaptation. Transport of folded proteins via T2SS nanomachines requires the assembly of inner membrane-anchored fibres called pseudopili. Although efficient pseudopilus assembly is essential for protein secretion, structure-based functional analyses are required to unravel the mechanistic link between these processes. Here, we report an atomic model for a T2SS pseudopilus from Klebsiella oxytoca, obtained by fitting the NMR structure of its calcium-bound subunit PulG into the ~5-A-resolution cryo-electron microscopy reconstruction of assembled fibres. This structure reveals the comprehensive network of inter-subunit contacts and unexpected features, including a disordered central region of the PulG helical stem, and highly flexible C-terminal residues on the fibre surface. NMR, mutagenesis and functional analyses highlight the key role of calcium in PulG folding and stability. Fibre disassembly in the absence of calcium provides a basis for pseudopilus length control, essential for protein secretion, and supports the Archimedes screw model for the type 2 secretion mechanism. An atomic model for a type 2 secretion system pseudopilus from Klebsiella oxytoca reveals a comprehensive network of inter-subunit contacts while mutational and functional analyses highlight the role of calcium in PulG folding and stability.

Herein, the radiolytic degradations of atrazine and cyanuric acid were performed via electron beam irradiation. The results demonstrated atrazine could be completely mineralized without any residue of cyanuric acid in aqueous solution. The degradation of atrazine followed the pseudo-first-order reaction kinetics. The studies in the presence of different radical scavengers (O2 and tert-butanol) indicated hydroxyl radicals were the main species for the decomposition of atrazine into cyanuric acid, while e−aq played vital role in the degradation of cyanuric acid. During the radiolysis processes of atrazine and cyanuric acid, some organic and inorganic intermediates were detected, implying dechlorination, dealkylation, and deamination occurred. On the basis of the effects of radicals and detected products, the potential radiolytic degradation pathways of atrazine via electron beam were proposed.

Dicyanomethylene-substituted quinoidal dithieno [2,3-d;2',3'-dlbenzo [1,2-b;4,5-b1 dithiophene compounds (QDTBDTs) with alkyl chains branched at different positions were synthesized. Thin-film transistor characteristics showed that the type of charge carriers in QDTBDTs could be tuned by changing the branching position of the alkyl chains. QDTBDT-2C exhibited n-channel behavior, and the observed electron mobility was 0.57 cm(2) V-1 s(-1) without post-treatment, one of the highest values reported for spin-coated thin-film transistors with no annealing under ambient conditions. QDTBDT-4C-based transistors displayed electron-dominated ambipolar transport behavior, with electron mobilities reaching 0.2 cm(2) V-1 s-i and hole mobilities in the range of 10-3-10-4 cm(2) V-1 s(-1). QDTBDT-3C showed solution-concentrationdependent carrier transport characteristics, exhibiting n-type behavior at low solution concentrations and ambipolar performance at high solution concentrations with an electron mobility of 0.22 cm(2) V-1 s(-1) and a hole mobility of 0.034 cm(2) V-1 s(-1). CMOSlike inverters fabricated from QDTBDT-2C displayed high gain and high noise margins.

A novel composite material of hierarchically structured platinum–ruthenium (PtRu) nanoparticles grown on large surface area three dimensional graphene foam (3D GF) is reported. 3D GF was incorporated with PtRu bimetallic nanoparticles as an electrochemical nanocatalyst for methanol and ethanol oxidation. PtRu/3D GF nanocatalyst showed a higher tolerance to poisoning by CO and exhibited improved catalytic activity for both methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). Cyclic voltammetry (CV) results and long-term cycling stability tests demonstrated that GF provided a promising platform for the development of electrochemical nanocatalysts. Specifically, PtRu/3D GF nanocatalyst showed excellent catalytic activity toward MOR and EOR compared with PtRu/Graphene (Commercial graphene), PtRu/C (Vulcan XC-72R carbon), and PtRu alone. The crystal size of PtRu on 3D GF was reduced to 3.5 nm and its active surface area was enhanced to 186.2 m 2 g −1 . Consequently, the MOR and EOR rates were nearly doubled on PtRu/3D GF compared to those on PtRu/Graphene.

It is well known that the flowing of oil and gas in fracture and cave does not obey Darcy law, which makes it unable to interpret parameters correctly when doing well testing for those kinds of formation for having no flowing test used to correct corresponding flowing equations. Based on similarity criterion, a physical experimental method for gas flowing from cave to wellbore through fracture has been built up. The characteristics of fluid flowing in fracture and cave can be seen clearly according to log–log curves with the measured data, which was obtained from the experimental model test and dealt with Savitzky-Golay filtering method. In addition, a new mathematical model reflecting those transient-flow behaviors as well as its solution has been presented in this paper. Log–log curves obtained from our new model could reflect the characteristics of flowing in fracture and cave. The results showed that test experiments can reflect the influence of large-scaled cave and fracture on the flowing characteristics and the new model can be applied to explain parameters of fracture and cave for similar cases.

Background Invasive fungal disease (IFD) has a poor prognosis in children with hematological disorders after hematopoietic stem cell transplantation (HSCT). We assessed if drug combinations with different targets may improve the outcome. Methods Retrospective study to assess the outcome of combination antifungal therapy (CAT) for proven-probable IFD (PP-IFD) in children with hematological disorders after HSCT from January 2008 to June 2018. Results Over the 10-year period, 95 PP-IFD were diagnosed in pediatric recipients, median age of 5.6 years. Twenty-seven patients received combinations of caspofungin and voriconazole, 28 patients received combinations of caspofungin and amphotericin B, and 40 patients received combinations of voriconazole and amphotericin B. The overall response rate of PP-IFD was 77.9%, while the 100-day overall survival rates were 66.8%. Univariate analysis showed that factors that significantly affected the response to combination treatments were type of combination (P = 0.02), the stem cell source (P = 0.04), the donor type (P = 0.03), HLA-match (P = 0.03), aGVHD (P = 0.02), period of treatment (P = 0.044), use of corticosteroids (0.036), CD4:CD8 ratio (P = 0.014), and CMV viremia (P = 0.033). In addition, multivariate analysis demonstrated that only the type of combination remained a significant factor (odds ratio = 0.335, 95% confidence interval: 0.071-0.812, P = 0.042). Forty-three children suffered from mild and reversible adverse reactions, no serious side effects during treatment. Conclusion A variety of factors can affect the outcome of CAT. Combination of caspofungin with voriconazole is a safe and helpful treatment option for HSCT recipients with IFD.

Tin oxide (SnO2) has attracted a lot of attention among lithium ion battery anode materials due to its rich reserves, high theoretical capacity, and safe potential. However, the mechanism of the SnO2 nano materials in the lithiation-delithiation reaction, especially whether the first-step conversion reaction is reversible, is still controversial. In this paper, SnO2 nanoparticles with an average particle size of 4.4 nm are successfully prepared via a simple hydrothermal method. A nanosized lithium ion battery that enables the in situ electrochemical experiments of SnO2 nanoparticles is constructed to investigate the electrochemical behavior of SnO2 in lithiation-delithiation process. Briefly, the nanosized electrochemical cell consists of a SnO2 working electrode, a metal lithium (Li) counter electrode on a sharp tungsten probe, and a solid electrolyte of lithium oxide (Li2O) layer naturally grown on the surface of metal Li. Then, the whole lithiation-delithiation process of SnO2 nanocrystals is tracked in real time. When a constant potential of –2 V is applied to the SnO2 with respect to lithium, lithium ions begin to diffuse from one side of the nanoparticles, which is in contact with the Li/Li2O layer, and gradually propagate to the other side. Upon the lithiation, a two-step conversion reaction mechanism is revealed: SnO2 is first converted into intermediate phase of Sn with an average diameter of 4.2 nm which is then further converted into Li22Sn5. Upon the delithiation, a potential of 2 V is applied and Li22Sn5 phase can be reconverted into SnO2 phase when completely delithiated. It is because the interfaces and grain boundaries of nano-sized SnO2 may impede the Sn diffusing from one grain into another during lithiation/delithiation and then suppress the coarsening of Sn, and enable the Li2O and Sn to be sufficiently contacted with each other and then converted into SnO2. This work provides a valuable insight into an understanding of phase evolution in the lithiation-delithiation process of SnO2 and the results are of great significance for improving the reversible capacity and cycle performance of lithium ion batteries with SnO2 electrodes.

The vast amount of methane deposits in permafrost and oceanic sediments has significant energy and environmental implications. There are increasing interests in the development of numerical simulation techniques to predict the reservoir responses due to natural gas recovery from methane hydrate dissociation. There has been extensive amount of work on modeling the chemo- thermo- hydro-responses associated with hydrate dissociation. The mechanical responses of hydrate bearing ground, however, have largely been overlooked and are just starting to receive more and more attention. From energy recovery perspective, a comprehensive model that includes the mechanical responses of hydrate disassociation is crucial for predicting the mechanical stability of gas hydrate reservoir and potential geohazards. This paper proposes a thermo-hydro-mechanical-chemical model for simulating the dissociation of methane hydrate. The governing equations for the conservation of energy (thermal), mass (hydraulic) and momentum (mechanical) were derived from the local balance equations. The proposed governing equation system for methane hydrate as a four-phase four-component composite was simplified based on reasonable assumptions to facilitate numerical implementations. The dissociation reaction was considered using chemical kinetics. Auxiliary relationships such as the soil water characteristic curve, constitutive correlations, stress formulation based on the mixture theory were employed to mathematically close the formulation. The mathematical model was implemented using the finite element method. The simulation results were evaluated and compared with those obtained by conventional simulators based on thermo-hydro-chemical models. The mechanical module of this new model was applied to predict the geotechnical responses induced by gas recovery in a typical oceanic reservoir.

Because of the addition of significant quantities of aluminum and manganese, the great challenge of casting 20Mn23Al nonmagnetic steel is to design a mold slag that is chemically compatible with this steel composition. A new mold slag with low melting point and low basicity was proposed. The initial slag (the base mold slag) and two corresponding mold slags sampled after 8 min and 15 min were investigated, and the changes of mold slag composition and properties of molten slag were discussed. The results showed that the slag quickly changed in chemical composition to a slag that contained a small quantity of silica and a larger quantity of alumina, and the basicity increased obviously; the heat flux density through the slag film decreased slightly compared with the slag film at 0 min, 8 min and 15 min; the mold slag used for nonmagnetic steel was precipitated as CaF2 crystals. The casting experiment shows that the slab has good surface quality without longitudinal face cracks and slag inclusions; the Al2O3 content in the molten slag pool increased with time at the beginning stage, and it can approach equilibrium state after about 600 s.

Homologous recombination mediated by RAD51 recombinase helps eliminate chromosomal lesions, such as DNA double-strand breaks induced by radiation or arising from injured DNA replication forks. The tumor suppressors BRCA2 and PALB2 act together to deliver RAD51 to chromosomal lesions to initiate repair. Here we document a new function of PALB2: to enhance RAD51's ability to form the D loop. We show that PALB2 binds DNA and physically interacts with RAD51. Notably, although PALB2 alone stimulates D-loop formation, it has a cooperative effect with RAD51AP1, an enhancer of RAD51. This stimulation stems from the ability of PALB2 to function with RAD51 and RAD51AP1 to assemble the synaptic complex. Our results demonstrate the multifaceted role of PALB2 in chromosome damage repair. Because PALB2 mutations can cause cancer or Fanconi anemia, our findings shed light on the mechanism of tumor suppression in humans., link_to_OA_fulltext

Proteins in the RecA/Rad51/RadA family form nucleoprotein filaments on DNA that catalyze a strand exchange reaction as part of homologous genetic recombination. Because of the centrality of this system to many aspects of DNA repair, the generation of genetic diversity, and cancer when this system fails or is not properly regulated, these filaments have been the object of many biochemical and biophysical studies. A recent paper has argued that the human Dmc1 protein, a meiotic homolog of bacterial RecA and human Rad51, forms filaments on single-stranded DNA with approximately 9 subunits per turn in contrast to the filaments formed on double-stranded DNA with approximately 6.4 subunits per turn and that the stoichiometry of DNA binding is different between these two filaments. We show using scanning transmission electron microscopy that the Dmc1 filament formed on single-stranded DNA has a mass per unit length expected from approximately 6.5 subunits per turn. More generally, we show how ambiguities in helical symmetry determination can generate incorrect solutions and why one sometimes must use other techniques, such as biochemistry, metal shadowing, or scanning transmission electron microscopy, to resolve these ambiguities. While three-dimensional reconstruction of helical filaments from EM images is a powerful tool, the intrinsic ambiguities that may be present with limited resolution are not sufficiently appreciated.

Using polystyrene (PS) opal templates and RF magnetron sputtering, three-dimensional (3D) zinc oxide (ZnO) photonic crystals (PCs) of core–shell structures are prepared. Scanning electron microscopic (SEM) spectra show that there are up to five layers in the samples while X-ray diffraction (XRD) spectra indicate that they are of hexagonal wurtzite structures, preferentially (0 0 2) oriented. Ultraviolet–visible (UV–vis) spectra confirm the existence of photonic band gaps (PBG) in the samples.

Bone marrow mesenchymal stem cells (BMSCs) have been shown to differentiate into cells of a neural lineage. However, no studies have examined whether gender influences the differentiation potential of BMSCs. Here, we explore the possible differences in BMSC's neurogenic potential in vitro between female rhesus monkey BMSCs (F-rhBMSCs) and male rhBMSCs (M-rhBMSCs). We first isolated and cultured rhBMSCs from female and male donors (n=6, 2 years old), identified their sex origin by karyotype assay, and assessed their expression of nestin and CD34 at passage 1 and 10. Then, nestin-positive F- and M-rhBMSCs at P10 were differentiated into neural-like cells. After induction, the neurogenic potential of these cells was assessed by morphological observation and protein expression analysis of neural markers, including class III beta-tubulin, neurofilament light polypeptide, tau, and gamma-aminobutyric acid (GABA) neurotransmitter. Furthermore, GABA content was assayed using high-pressure liquid chromatography. The results showed that F-rhBMSCs produced significantly more nestin-positive cells compared with M-rhBMSCs at P10 and that nestin-positive F-rhBMSCs acquired higher neurogenic potential accompanied by increased synthesis and excretion of GABA compared with nestin-positive M-rhBMSCs under conditions of differentiation. These results indicated that gender may play an important role in the neurogenic potential of BMSCs, and a further understanding of the cellular biology underlying these differences may contribute to the development of new therapeutic strategies for neurological repair and regeneration.

Studying solute transport in soils is hampered by a lack of technology for continuously monitoring ionic concentration of contaminants. The electrical conductivity of pore water is a strong indicator of ionic concentration of contamination in soil. Using the bulk electrical conductivity of a soil measured by time domain reflectrometry (TDR) to predict the soil pore-water electrical conductivity appears to be a promising technique. This study presents a new method for estimating the pore-water electrical conductivity of saturated sandy soils using a single TDR test. The effects of pore-water electrical conductivity, temperature, porosity, and ionic types on the electrical conductivity of soil were studied. An average value of the exponent in the Archie’s Law was found to be 1.457 for the saturated sandy soils used in this study. A laboratory model infiltration test was also conducted with continuous monitoring of the electrical conductivity of the pore water by TDR. The results showed that TDR is able to provide a reasonably accurate estimation of the electrical conductivity of pore water. Consequently, it may be possible to monitor the in situ ionic contamination in saturated sandy soils using TDR technology.

The E. coli RecBCD enzyme facilitates the loading of RecA onto single-stranded DNA produced by the combined helicase/nuclease activity of RecBCD. The nuclease domain of RecB protein, RecB(nuc), has been previously shown to bind RecA. Surprisingly, RecB(nuc) also binds to phage and eukaryotic homologs of RecA, leading to the suggestion that RecB(nuc) interacts with the polymerization motif that is present in all three proteins. This mode of interaction could only be with monomeric RecA, as this motif would be buried in filaments. We show that RecB(nuc) binds extensively to the outside of RecA-DNA filaments. Three-dimensional reconstructions suggest that RecB(nuc) binds to the ATP-binding core of RecA, with a displacement of the C-terminal domain of RecA. Solution experiments confirm that the interaction of RecB(nuc) is only with the RecA core. Since the RecA C-terminal domain has been shown to be regulatory, the interaction observed may be part of the loading mechanism where RecB displaces the RecA C-terminal domain and activates a RecA monomer for polymerization.

Excess aluminum (Al) ions and phosphorus (P) deficiency are the key factors that limit plant growth in acid soils. Secretion of organic acids (OA) from roots has been proposed as an Al-resistance mechanism. Nonetheless, the correlation between Al resistance and this mechanism has not been tested beyond a very small number of Al-resistant and Al-sensitive genotypes. To elucidate the mechanisms responsible for plant adaptability to acid soils, we studied the secretion of OA from roots of Stylosanthes in response to high-Al and low-P stresses using six different genotypes. Relative root inhibition by 50 µM Al ranged from 25–71% and differed significantly among six Stylosanthes genotypes. Al treatment induced the secretion of citrate from the roots of Stylosanthes seedling in a dose- and time-dependent manner. Moreover, the secretion rate was significantly higher in the Al-resistant genotype. On the other hand, inhibition of Al-induced citrate secretion by phenylisothiocyanate or 9-anthracenecarboxylic acid resulted in an increase in Al content in Stylosanthes root apices. P deficiency also induced citrate secretion from Stylosanthes seedling roots. Furthermore, citrate secretion was much more robust with exposure to both excess-Al and P-deficiency stresses than under either stress alone. Unlike Al-induced citrate secretion, which was rapid, low-P-induced secretion was a slow process, with significant increases in secretion only becoming evident after 6 d of treatment with free phosphate. The lag between treatment with Al and citrate secretion was approximately 4 h. These results suggest that the secretion of citrate is a mechanism for resistance to both excess-Al and low-P stresses in Stylosanthes.

A short, elegant, and high yielding synthesis of ravoconazole is presented. The key step of this synthesis is an enantioselective palladium-catalyzed chiral zinc-allene addition reaction. The starting materials are 2-chloro-1-(2,4-difluorophenyl)-ethanone and (R)-4-phenylbutyn-2-ol obtained from enzymatic resolution of its racemate.

Previous studies showed that the K342E substitution in the Saccharomyces cerevisiae Rad51 protein increases the interaction with Rad54 protein in the two-hybrid system, leads to increased sensitivity to the alkylating agent MMS and hyper-recombination in an oligonucleotide-mediated gene targeting assay. K342 localizes in loop 2, a region of Rad51 whose function is not well understood. Here, we show that Rad51-K342E displays DNA-independent and DNA-dependent ATPase activities, owing to its ability to form filaments in the absence of a DNA lattice. These filaments exhibit a compressed pitch of 81 A, whereas filaments of wild-type Rad51 and Rad51-K342E on DNA form extended filaments with a 97 A pitch. Rad51-K342E shows near normal binding to ssDNA, but displays a defect in dsDNA binding, resulting in less stable protein-dsDNA complexes. The mutant protein is capable of catalyzing the DNA strand exchange reaction and is insensitive to inhibition by the early addition of dsDNA. Wild-type Rad51 protein is inhibited under such conditions, because of its ability to bind dsDNA. No significant changes in the interaction between Rad51-K342E and Rad54 could be identified. These findings suggest that loop 2 contributes to the primary DNA-binding site in Rad51, controlling filament formation and ATPase activity.

Endothelial cells assemble von Willebrand factor (VWF) multimers into ordered tubules within storage organelles called Weibel–Palade bodies, and tubular packing is necessary for the secretion of VWF filaments that can bind connective tissue and recruit platelets to sites of vascular injury. We now have recreated VWF tubule assembly in vitro , starting with only pure VWF propeptide (domains D1D2) and disulfide-linked dimers of adjacent N-terminal D′D3 domains. Assembly requires low pH and calcium ions and is reversed at neutral pH. Quick-freeze deep-etch electron microscopy and three-dimensional reconstruction of negatively stained images show that tubules contain a repeating unit of one D′D3 dimer and two propeptides arranged in a right-handed helix with 4.2 units per turn. The symmetry and location of interdomain contacts suggest that decreasing pH along the secretory pathway coordinates the disulfide-linked assembly of VWF multimers with their tubular packaging.

Summary Repair of DNA double strand breaks by homologous recombination (HR) is initiated by Rad51 filament nucleation on single-stranded DNA (ssDNA), which catalyzes strand exchange with homologous duplex DNA. BRCA2 and the Rad51 paralogs are tumor suppressors and critical mediators of Rad51. To gain insight into Rad51 paralog function, we investigated a heterodimeric Rad51 paralog complex, RFS-1/RIP-1, and uncovered the molecular basis by which Rad51 paralogs promote HR. Unlike BRCA2, which nucleates RAD-51-ssDNA filaments, RFS-1/RIP-1 binds and remodels pre-synaptic filaments to a stabilized, “open,” and flexible conformation, in which the ssDNA is more accessible to nuclease digestion and RAD-51 dissociation rate is reduced. Walker box mutations in RFS-1, which abolish filament remodeling, fail to stimulate RAD-51 strand exchange activity, demonstrating that remodeling is essential for RFS-1/RIP-1 function. We propose that Rad51 paralogs stimulate HR by remodeling the Rad51 filament, priming it for strand exchange with the template duplex., Graphical Abstract, Highlights • A Rad51 paralog complex, RFS-1/RIP-1, binds RAD-51-ssDNA pre-synaptic filaments • RFS-1/RIP-1 stabilizes the filament by reducing RAD-51 dissociation from ssDNA • RFS-1/RIP-1 remodels the pre-synaptic complex to a more “open,” flexible conformation • Pre-synaptic complex remodeling stimulates strand exchange and recombination, Rad51 paralogs, known tumor suppressors, induce remodeling at the tips of Rad51-ssDNA filaments to form an open and flexible conformation that promotes homologous recombination.

A viral DNA form that survives extremes The prokaryote Sulfolobus islandicus lives at extreme temperatures (∼80°C) and acidity (pH 3). It is infected by the rudivirus SIRV2. DiMaio et al. determined the structure of the SIRV2 virus using cryo–electron microscopy to understand how the virus survives these brutal conditions. Most DNA in nature assumes a B-form shape. The virion, on the other hand, contains highly unusual A-form DNA that may help it survive adverse conditions. The viral capsid protein forms an extended α-helical structure that wraps around the viral DNA, possibly stabilizing the A-form DNA. Science , this issue p. 914