bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrasensitive high‐performance liquid chromatography determination of tetracycline antibiotics and their 4‐epimer derivatives based on dual effect of methanesulfonic acid
Authors: Lai Xiaojing , Liu Jing , Xu Xin , Li Jie , Zhang Baojun , Wei Lijun , Cai Hongping , Cheng Xianglei 
Published: October 2019

AbstractIn reversed‐phase liquid chromatography, tetracycline antibiotics yield broad and asymmetrical peaks, as a result of their ionic interaction with the anionic free silanol groups and metal ion present in the silica‐based stationary phases (commonly derivatized with C18 groups). These frequently encountered difficulties were absolutely eliminated based on dual effect when methanesulfonic acid was employed as an eluent additive. The study revealed that the performance of methanesulfonic acid to minimize the “silanol effect” is mainly explained by both direct neutralization of the anionic silanol sites and electrostatic attraction with analytes. Based on these dual action mechanisms, an ultrasensitive method has been successfully developed for the simultaneous determination of tetracycline antibiotics and their derivatives (minocycline, oxytetracycline, tetracycline, chlortetracycline, metacycline, doxycycline, 4‐epitetracycline, and 4‐epichlortetracycline) in bovine milk with convenient ultraviolet detection within 15 min. Under the optimal conditions, the calibration curves showed good linearity (r2 > 0.999) for all analytes in the range of 1∼200 ng/mL with the instrument limits of detection as low as 0.3 ng/mL. The study sheds new light on suitable additives to analyze basic compounds with the advantage of good compatibility with MS detection.
Kinetics studies of 5‐methyl‐2‐hexanol, 2,2‐dimethyl‐3‐hexanol, and 2,4,4‐trimethyl‐1‐pentanol with chlorine atoms: Photooxidation mechanism of 2,4,4‐trimethyl‐1‐pentanol
Authors: Vila Jesús A. , Argüello Gustavo A. , Malanca Fabio E. 
Published: October 2019

AbstractThe rate constants for the reaction between chlorine atoms and either 5‐methyl‐2‐hexanol, 2,2‐dimethyl‐3‐hexanol, or 2,4,4‐trimethyl‐1‐pentanol at 298 K were determined using the relative method with 2‐butanol and 1‐pentanol as reference compounds. The values obtained for 5‐methyl‐2‐hexanol, 2,2‐dimethyl‐3‐hexanol, and 2,4,4‐trimethyl‐1‐pentanol (k × 1010 cm3 molec−1 s−1) were, respectively, (2.64 ± 0.5), (2.72 ± 0.5), and (2.50 ± 0.4), in agreement with the values of the rate constants reported in bibliography for similar alcohols and the values estimated by structure activity relationship methods. The photooxidation products of 2,4,4‐trimethyl‐1‐pentanol initiated by chlorine atoms were identified (formaldehyde, 2‐propanone, 2,2‐dimethyl propanal, 4,4,‐dimethyl‐2‐pentanone, and 3,3‐dimethylbutanal), and the reaction mechanism was determined.
Implementing Efficient Peptoid‐Mediated Delivery of RNA‐Based Therapeutics to the Vocal Folds
Authors: Mukudai Shigeyuki , Kraja Iv , Bing Renjie , Nalband Danielle M. , Tatikola Mallika , Hiwatashi Nao , Kirshenbaum Kent , Branski Ryan C. 
Published: October 2019

ObjectiveWe hypothesize that Smad3 is a master regulator of fibrosis in the vocal folds (VFs) and RNA‐based therapeutics targeting Smad3 hold therapeutic promise. Delivery remains challenging. We previously described a novel synthetic peptoid oligomer, lipitoid L0, complexed with siRNA to improve stability and cellular uptake. An advantage of these peptoids, however, is tremendous structural and chemical malleability to optimize transfection efficiency. Modifications of L0 were assayed to optimize siRNA‐mediated alteration of gene expression.MethodsIn vitro, Smad3 knockdown by various lipitoid variants was evaluated via quantitative real‐time polymerase chain reaction in human VF fibroblasts. Cytotoxicity was quantified via colorimetric assays. In vivo, a rabbit model of VF injury was employed to evaluate the temporal dynamics of Smad3 knockdown following injection of the L0‐siRNA complex.ResultsIn vitro, similar reductions in Smad3 expression were established by all lipitoid variants, with one exception. Sequence variants also exhibited similar nontoxic characteristics; no statistically significant differences in cell proliferation were observed. In vivo, Smad3 expression was significantly reduced in injured VFs following injection of L0‐complexed Smad3 siRNA at 1 day postinjection. Qualitative suppression of Smad3 expression persisted to 3 days following injury, but did not achieve statistical significance.ConclusionsIn spite of the chemical diversity of these peptoid transfection reagents, the sequence variants generally provided consistently efficient reductions in Smad3 expression. L0 yielded effective, yet temporally limited knockdown of Smad3 in vivo. Peptoids may provide a versatile platform for the discovery of siRNA delivery vehicles optimized for clinical application.Level of EvidenceNA
A Bio‐Inspired and Biomass‐Derived Healable Photochromic Material Induced by Hierarchical Structural Design
Authors: Wu Bo , Lei Yuan , Xiao Yao , Wang Yanjun , Yuan Ye , Jiang Liang , Zhang Xi , Lei Jingxin 
Published: October 2019

AbstractUtilization of bionics to develop stimuli responsive polymers that can heal damage with excellent restorability is particularly attractive for a sustainable society. Herein, inspired by chameleons, a hierarchical structural design strategy is proposed and illustrated to fabricate a healable photochromic material based on a self‐healable polymeric matrix and a finely dispersed photochromic spirooxazine. The self‐healable polymeric matrix is fabricated via the integration of multiple hydrogen bonds (H bonds) and covalent cross‐links into a biomass‐derived elastomer. The dynamic nature and soft characteristics enable the as‐prepared elastomer superior extensibility as well as self‐healing ability, while the covalent cross‐links can assist the reassociation of ruptured H bonds. The representative elastomer exhibits an extensibility of 2600% and toughness of 42.76 MJ m−3. Furthermore, it shows good self‐healing ability with complete recovery of scratch as well as restoration against 1900% of elongation and 24.1 MJ m−3 of toughness after healing at 60 °C for 24 h. This combination of moderate toughness, good self‐healing ability, and smart photochromic property in biomass‐derived materials should largely improve their applicability, reliability, and sustainability in various materials and devices.
Mesoporous Silica Micromotors with a Reversible Temperature Regulated On–Off Polyphosphazene Switch
Authors: Kneidinger Michael , Iturmendi Aitziber , Ulbricht Christoph , Truglas Tia , Groiss Heiko , Teasdale Ian , Salinas Yolanda 
Published: October 2019

AbstractThe incorporation of an extraneous on–off braking system is necessary for the effective motion control of the next generation of micrometer‐sized motors. Here, the design and synthesis of micromotors is reported based on mesoporous silica particles containing bipyridine groups, introduced by cocondensation, for entrapping catalytic cobalt(II) ions within the mesochannels, and functionalized on the surface with silane‐derived temperature responsive bottle‐brush polyphosphazene. Switching the polymers in a narrow temperature window of 25–30 °C between the swollen and collapsed state, allows the access for the fuel H2O2 contained in the dispersion medium to cobalt(II) bipyridinato catalyst sites. The decomposition of hydrogen peroxide is monitored by optical microscopy, and effectively operated by reversibly closing or opening the pores by the grafted gate‐like polyphosphazene, to control on demand the oxygen bubble generation. This design represents one of the few examples using temperature as a trigger for the reversible on–off external switching of mesoporous silica micromotors.
Method for the facile transformation of marine purple photosynthetic bacteria using chemically competent cells
Authors: Higuchi‐Takeuchi Mieko , Morisaki Kumiko , Numata Keiji 
Published: October 2019

AbstractMarine purple photosynthetic bacteria are ideal organisms for the production of useful materials at reduced costs and contributing to a sustainable society because they can utilize sunlight, seawater, and components of air, including carbon dioxide and nitrogen gases, for their growth. However, conjugation is the only applicable method for the transformation of marine purple photosynthetic bacteria so far. Here, we examined a calcium chloride‐mediated method for the transformation of marine purple photosynthetic bacteria. Plasmid DNAs containing the kanamycin resistance gene were successfully transferred into chemically competent cells of two strains of marine purple photosynthetic bacteria (Rhodovulum sulfidophilum and Roseospira marina). Heat shock treatment increased the transformation efficiency in R. sulfidophilum, whereas the addition of cell‐penetrating peptide did not improve it. We also found that prolonged incubation in agar plates containing kanamycin led to spontaneous mutation of the 16S rRNA, resulting in kanamycin resistance in R. marina. Thus, we developed an efficient and facile transformation method using chemically competent cells of marine purple photosynthetic bacteria with calcium chloride.
Nonlinearity effect on dual photonic crystal fiber coupler for generating fully optical logic gates
Authors: Filho A. F. G. F. , Cavalcante T. X. , Beserra C. C. , Costa M. B. C. , Batista G. S. , Lima S. V. , Freire M. M. , Sousa J. R. R. , Sombra A. S. B. 
Published: October 2019

AbstractIn this work, we present a numerical investigation of the asymmetric double nonlinear coupling of photonic crystal fibers in an on‐off switch to obtain fully optical logic gates. Ultra‐short pulses (100 fs) are propagated through the device in three distinct excitation power regimes, power below critical (Po = 72 kW, where Po represents the excitation power of the device), critical power (Pc = 103.5 kW, where Pc represents critical Power for which the power switching is 50% for both guides. There are cases where Po is above the critical value, there are cases that is below), and power above critical (Po = 110 kW). The pulse switching characteristics are analyzed as a function of the input power and the nonlinearity profile (β‐beta) inserted in one of the component guides. The nonlinearity profiles follow the regimes: constant, increasing and decreasing, and high order effects, such as third‐order dispersion, intrapulse Raman scattering and self‐steepening are included in the generalized Schrödinger nonlinear equation governs the pulse propagation dynamics. The results show that the proposed device can be used to obtain AND, OR, and NOT logic gate. Numerical studies were done from the coupled‐coupled equations solved using the fourth‐order Runge‐Kutta method, using MATLAB as a programming tool for solving equations. The implementation of fully optical logic gates tends to revolutionize new digital systems in the field of data storage, such as optical memory, “replacement” of electronic circuits among other applications. Optical systems have a great advantage as they are free from electromagnetic interference and have high rates of data transmission.
A compact dual‐band dual‐mode antenna for GPS L1/L2 adaptive interference cancellation
Authors: Rezazadeh Navid , Shafai Lotfollah 
Published: October 2019

AbstractA dual‐band dual‐mode microstrip antenna design is presented, with the application of adaptive interference cancellation in global positioning system at the L1 and L2 bands. The antenna consists of two stacked TM11 rings and two stacked TM21 shorted rings all fed by coaxial probes. By properly combining the two modes and utilizing both polarization components of each mode, up to three nulls can be steered at each frequency band to cancel interferers close to horizon. The concentric structure of the radiating patches in the proposed design allows for a compact antenna, which for a substrate of dielectric constant of 10 is only 0.33 λ in diameter at its lowest frequency of operation and can be further miniaturized on a higher dielectric constant substrate.
Q‐switching pulses generation with samarium oxide film saturable absorber
Authors: Zulkipli Nur F. , Batumalay Malathy , Samsamnun Farina S. M. , Mahyuddin Mohamad B. H. , Izam Tengku F. T. M. N. , Khudus Muhammad I. M. A. , Harun Sulaiman W. 
Published: October 2019

AbstractQ‐switching pulses generation in an erbium‐doped fiber laser (EDFL) was demonstrated by using a samarium oxide (Sm2O3) film as a saturable absorber (SA) for the first time. The passively Q‐switched EDFL operated stably at 1567 nm with tunable repetition rates, ranging from 47 to 66 kHz with the increase in pump power from 51.0 to 88.1 mW. At 88.1 mW pump power, the maximum pulse energy and the minimum pulse width were obtained at 26 nJ and 5.6 μs, respectively. These results demonstrated that the proposed Sm2O3 SA is viable for the construction of a flexible and reliably stable Q‐switched pulsed fiber laser in the 1.5 μm region.
A pattern diversity antenna with six input ports
Authors: Row Jeen‐Sheen , Kuo Li‐Kai 
Published: October 2019

AbstractA wideband antenna with conical radiation is first studied in this article. The antenna has the advantages of low profile and simple structure, and it can provide a stable radiation pattern within an impedance bandwidth of about 108%. Then, five radiating elements, including four dipole antennas and one ring slot antenna, are excited from the wideband antenna structure, forming a six‐port antenna. The integrated antenna at 3.5 GHz band can offer a broadside pattern with 9.3 dBi gain, a conical pattern with 4.3 dBi gain, and four symmetrical endfire patterns with 6.4 dBi gain. The design process of the integrated antenna is explained in details, and a prototype is fabricated. The experimental results indicate that the operation bandwidth of the pattern diversity antenna is about 14%, and the isolation between input ports is lower than −16 dB within the bandwidth. Simulated results also validate the experiments.
CD70 expression correlates with a worse prognosis in malignant pleural mesothelioma patients via immune evasion and enhanced invasiveness
Authors: Inaguma Shingo , Lasota Jerzy , Czapiewski Piotr , Langfort Renata , Rys Janusz , Szpor Joanna , Waloszczyk Piotr , Okoń Krzysztof , Biernat Wojciech , Schrump David S , Hassan Raffit , Kasai Kenji , Miettinen Markku , Ikeda Hiroshi 
Published: October 2019

AbstractDiffuse malignant mesothelioma of the pleura (MPM) is a highly aggressive tumour that typically is associated with short survival. CD70 and CD27 belong to the tumour necrosis factor (TNF) and the TNF receptor (TNFR) superfamily, respectively. Under physiological conditions, the tightly regulated interaction between CD70 and CD27 plays a co‐stimulatory role in promoting T‐cell expansion and differentiation through the NFκB pathway. Aberrantly high CD70 expression has been documented in haematological and solid malignancies in association with immune evasion in malignant cells. In this study, 172 well‐characterised primary diffuse MPM tumours including epithelioid (n = 145), biphasic (n = 15), and sarcomatoid (n = 12) histotypes were evaluated immunohistochemically for CD70, CD27, CD3, CD4, CD8, CD56, PDCD1 (PD‐1), and FOXP3 expression. Twenty per cent (34/172) of the mesothelioma cells expressed CD70 on the cell membrane. Overall survival was significantly decreased in the cohort of patients with CD70‐expressing tumour cells (p < 0.01). Patients with MPM containing a higher number of CD3+ (p < 0.01), CD4+ (p < 0.01), CD8+ (p < 0.01), or FOXP3+ (p < 0.01) tumour‐infiltrating lymphoid cells (TILs) showed significantly worse clinical outcomes. As potential independent risk factors for MPM patients, multivariate Cox proportional hazards regression analysis revealed CD70 expression on mesothelioma cells [hazard ratio (HR) 2.25; p = 0.010], higher FOXP3+ TILs (HR 2.81; p = 0.004), and higher CD3+ TIL accumulation (HR 6.12; p < 0.001). In contrast, as a potential independent favourable factor, higher CD27+ TIL accumulation (HR 0.48; p = 0.037) was identified. In vitro experiments and an immunodeficient mouse model revealed that CD70 enhances the invasiveness of MPM cells through MET–ERK axis activation. Further analyses in syngeneic mouse models demonstrated possible roles for CD70 in immune evasion. Collectively, these findings suggest that the CD70–CD27 pathway enhances the malignant phenotypes of MPM and diminishes anti‐tumor immune response in patients with these neoplasms. These markers might be useful in MPM for prognostic evaluations as well as targeted therapeutics. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Study on the Fracture Properties of HTPB Propellant at Low Temperature
Authors: Long Bing , Wang Hongliang , Gao Shuangsheng 
Published: October 2019

AbstractIn order to study the fracture behaviour of hydroxyl‐terminated polybutadiene (HTPB) propellant, the low temperature fracture toughness experiment of HTPB propellant was carried out by using centrally cracked sheet tensile specimens. The fracture toughness values of HTPB propellant with mode I crack at different temperature and loading rate were obtained, and the effect of specimen thickness on the fracture toughness was investigated. The experimental results show that the fracture toughness value continuously increases with the decreasing of temperature and the increasing of loading rate, and a linear relationship exists between the fracture toughness and the logarithm of loading rate. The effect on the fracture toughness by the change in loading rate is more notable at a lower temperature. Both at 25 °C and −40 °C, the fracture toughness of thick specimens is higher than that of thin specimens, and at low temperature the change is more obvious. A master curve of quadratic function for the fracture toughness was obtained. The influence of temperature on the fracture toughness is more obvious than that of the strain rate with double factor analysis of variance.
Explosion mitigation of methane‐air mixture in combined application of inert gas and ABC dry powders in a closed compartment
Authors: Li Manhou , Xu Jingchao , Li Quan , Wang Changjian , Wang Baozhen , Jiang Jiacheng 
Published: October 2019

AbstractThe explosion is one of the most serious safety incidents occurring in the application of the gas methane in industrial process. The new developments in attenuating the destruction and environmental hazard of this explosion are conducted using the combined inert gas and ABC dry powder. The explosive characteristic parameters including flame configuration, velocity of flame propagation, explosion pressure, and pressure rising rate are quantified and revealed. The difference of explosion mitigation effect of ordinary and ultra‐fine ABC dry powders are examined based upon the specific surface area and the settling velocity. As the concentration of ordinary or ultra‐fine ABC dry powder increases, the explosion pressure initially increases and decreases afterwards, indicating that there is an optimal mass concentration of explosion mitigation for both powders. The effect of ignition delay time on the explosion mitigation of ultra‐fine ABC dry powder is characterized on the basis of the turbulent lever and the dry powder particle settling state. Moreover, the mechanisms of explosion mitigation with CO2 and the ultra‐fine ABC dry powder are fully revealed both on the physical and chemical properties. The present research provides basic data and theoretical guidance for prevention and controlling of gas explosion accidents.
Is the skin an important exposure route for workers during cyanogen fumigation?
Authors: Gaskin Sharyn , Thredgold Leigh , Pisaniello Dino , Logan Michael , Baxter Christina 
Published: October 2019

AbstractBACKGROUNDCyanogen is a toxic flammable gas used as a fumigant in numerous industries. Occupational exposure to cyanogen can occur during its production and use. The most serious human health risk from exposure to cyanogen is via the respiratory system. However, there is also potential for skin exposure in many workplace situations. The extent of skin absorption under occupational exposure scenarios has not been directly assessed. Understanding skin uptake potential may inform risk assessment and exposure control measures.RESULTSWe describe an in vitro experimental system using human epidermis and dynamic atmosphere exposure to cyanogen to mimic potential workplace exposures. The influence of clothing and ventilation on skin permeation outcomes were also assessed. No evidence of transdermal permeation was found at 100 or 1000 ppm exposures, while permeation of 0.99 ± 0.38 μg cm−2 was observed after 60 min exposure to 10 000 ppm. Fabric on skin and skin ventilation had no additional influence on transdermal permeation compared with naked skin, but fabric provided a reservoir for potential secondary exposures.CONCLUSIONResults show dermal uptake following cyanogen exposure is possible, but only at very high atmospheric concentrations (10 000 ppm after >15 min exposure). Importantly, this could have implications for fumigant applicators who may only be wearing personal respiratory protection. These empirical data may be used in conjunction with other relevant toxicological information in determining whether a Skin Notation is warranted for Workplace Exposure Standard setting. © 2019 Society of Chemical Industry
A Molecule‐Based Single‐Photon Source Applied in Quantum Radiometry
Authors: Lombardi Pietro , Trapuzzano Marco , Colautti Maja , Margheri Giancarlo , Degiovanni Ivo Pietro , López Marco , Kück Stefan , Toninelli Costanza 
Published: October 2019

AbstractSingle‐photon sources (SPSs) based on quantum emitters hold promise in quantum radiometry as metrology standard for photon fluxes at the low light level. Ideally this requires control over the photon flux in a wide dynamic range, sub‐Poissonian photon statistics, and narrow‐band emission spectrum. In this work, a monochromatic SPS based on an organic dye molecule is presented, whose photon flux is traceably measured to be adjustable between 144 000 and 1320 000 photons per second at a wavelength of (785.6 ± 0.1) nm, corresponding to an optical radiant flux between 36.5 and 334 fW. The high purity of the single‐photon stream is verified, with a second‐order autocorrelation function at zero time delay below 0.1 throughout the whole range. Such molecule‐based SPS is hence used for the calibration of a single‐photon avalanche detector against a low‐noise analog photodiode traceable to the primary standard for optical radiant flux (i.e., the cryogenic radiometer). Due to the narrow bandwidth of the source, corrections to the detector efficiency arising from the spectral power distribution are negligible. With this major advantage, the developed device may finally realize a low‐photon‐flux standard source for quantum radiometry.
A first look at blockchain‐based decentralized applications
Authors: Wu Kaidong , Ma Yun , Huang Gang , Liu Xuanzhe 
Published: October 2019

SummaryWith the increasing popularity of blockchain technologies in recent years, blockchain‐based decentralized applications (DApps for short in this paper) have been rapidly developed and widely adopted in many areas, being a hot topic in both academia and industry. Despite of the importance of DApps, we still have quite little understanding of DApps along with its ecosystem. To bridge the knowledge gap, this paper presents the first comprehensive empirical study of blockchain‐based DApps to date, based on an extensive dataset of 995 Ethereum DApps and 29,846,075 transaction logs over them. We make a descriptive analysis of the popularity of DApps, summarize the patterns of how DApps use smart contracts to access the underlying blockchain, and explore the worth‐addressing issues of deploying and operating DApps. Based on the findings, we propose some implications for DApp users to select proper DApps, for DApp developers to improve the efficiency of DApps, and for blockchain vendors to enhance the support of DApps.