bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesis of Cu nanoparticles supported on carbon nanotubes and its catalytic performance under different test conditions
Authors: Li Chun‐xiao , Huang Ru‐ting , Shi Xian‐yang 
Published: January 2020

AbstractBACKGROUND4‐Nitrophenol (4‐NP) is used widely in pesticides and other areas, but it can cause adverse environmental effects. Thus, it is desirable to convert it to 4‐aminophenol (4‐AP). Microbial synthesis of nanomaterials has the characteristics of low cost and effective control of secondary pollution. The catalytic performance of biosynthesized nanocomposites of copper (Cu) and carbon nanotubes (CNTs) in reducing 4‐NP to 4‐AP was evaluated.RESULTSHere, Cu nanoparticles were supported in situ on CNT nanocomposites via Shewanella oneidensis MR‐1 to form Cu/CNT nanocomposites. The prepared Cu/CNTs nanocomposites were characterized by transmission electron microscopy, X‐ray photoelectron spectroscopy, Raman spectrometry, and energy dispersed X‐ray spectroscopy. The findings showed that the Cu nanoparticles were successfully synthesized on the surface of the CNTs and that they had a typical diameter of 4 to 10 nm and high crystallinity. The catalytic performance of the nanocomposites for the reduction of 4‐NP was evaluated under different initial concentrations of Cu/CNT, pH, and temperatures. The best catalytic performance, in which 99.5% 4‐NP was reduced, was obtained with 3 wt% Cu/CNT at 45 °C and pH of 10 within 80 min. Accordingly, 4‐NP degradation followed first‐order kinetics, and the rate constant (k) has been calculated to be 0.0532 min−1. The Cu/CNT nanocomposite exhibited high stability catalytic efficiency at 95.2% even after six reaction cycles.CONCLUSIONThe study demonstrates an environmentally friendly method for synthesizing non‐noble metal nanocomposites and using them for the catalytic reduction of 4‐NP. The method could be applied to prepare other efficient and reusable metallic nanocatalysts. © 2020 Society of Chemical Industry
Polyhydroxyalkanoate (PHA) purification through dilute aqueous ammonia digestion at elevated temperatures
Authors: Burniol‐Figols Anna , Skiadas Ioannis V. , Daugaard Anders E. , Gavala Hariklia N. 
Published: January 2020

AbstractBACKGROUNDPurification of polyhydroxyalkanoates (PHA) is a challenging step, given the difficulty of achieving high PHA purity, while maintaining polymer integrity, in a sustainable and cost‐efficient manner. This study evaluated the potential of dilute ammonia digestion as a method to purify PHA from mixed microbial consortia.RESULTSDigestion temperatures were critical to the obtainable purity and the amount of recovered PHA. At temperatures below 75 °C (regardless of the incubation time and ammonia concentration), a low PHA recovery (down to 65%) and no increase in purity was observed. By increasing the temperature above 75 °C, a significantly higher PHA purity and higher recovery (above 90%) could be achieved. Temperatures maximizing the purity (140 °C) led to a detrimental reduction in the molar mass of the isolated PHA, but the use of a sonication pre‐treatment enabled to increase the purity at temperatures leading to limited molar mass loss (75–115 °C). The impurities still present in the recovered PHA did not compromise its thermal stability, and no significant degradation occurred during melting of PHA with 86% purity (comparably to pure chloroform‐extracted PHA). Conversely, PHA recovered through sulphuric acid (H2SO4) digestion underwent severe degradation during melting, despite presenting higher purity (98%).CONCLUSIONSHigh PHA purity, recovery and thermal stability can be obtained with dilute ammonia digestion. These observations, combined with the possibility of reusing ammonia within the process, make this method a promising approach for a more sustainable purification of PHA. © 2020 Society of Chemical Industry
HIV seroconcordance among heterosexual couples in rural KwaZulu‐Natal, South Africa: a population‐based analysis
Authors: Kim Hae‐Young , Harling Guy , Vandormael Alain , Tomita Andrew , Cuadros Diego F , Bärnighausen Till , Tanser Frank 
Published: January 2020

AbstractIntroductionHigh levels of HIV seroconcordance at the population level reduce the potential for effective HIV transmission. However, the level of HIV seroconcordance is largely unknown among heterosexual couples in sub‐Saharan Africa. We aimed to quantify the population level HIV seroconcordance in stable heterosexual couples in rural South Africa.MethodsWe followed adults (≥15 years old) using a population‐based, longitudinal and open surveillance system in KwaZulu‐Natal, South Africa, from 2003 to 2016. Sexual partnerships and HIV status were confirmed via household surveys and annual HIV surveillance. We calculated the proportions of HIV seroconcordance and serodiscordance in stable sexual partnerships and compared them to the expected proportions under the assumption of random mixing using individual‐based microsimulation models. Among unpartnered individuals, we estimated the incidence rates and hazard of sexual partnership formation with HIV‐positive or HIV‐negative partners by participants' own time‐varying HIV status. Competing risks survival regressions were fitted adjusting for sociodemographic and clinical factors. We also calculated Newman's assortativity coefficients.ResultsA total of 18,341 HIV‐negative and 11,361 HIV‐positive individuals contributed 154,469 person‐years (PY) of follow‐up. Overall, 28% of the participants were in stable sexual partnerships. Of the 677 newly formed stable sexual partnerships, 7.7% (95% CI: 5.8 to 10.0) were HIV‐positive seroconcordant (i.e. both individuals in the partnership were HIV‐positive), which was three times higher than the expected proportion (2.3%) in microsimulation models based on random mixing. The incidence rates of sexual partnership formation were 0.54/1000PY with HIV‐positive, 1.12/1000PY with HIV‐negative and 2.65/1000PY with unknown serostatus partners. HIV‐positive individuals had 2.39 (95% CI: 1.43 to 3.99) times higher hazard of forming a sexual partnership with an HIV‐positive partner than did HIV‐negative individuals after adjusting for age, opposite‐sex HIV prevalence (by 5‐years age groups), HIV prevalence in the surrounding community, ART coverage and other sociodemographic factors. Similarly, forming a sexual partnership with an HIV‐negative partner was 1.47 (95% CI: 1.01 to 2.14) times higher in HIV‐negative individuals in the adjusted model. Newman's coefficient also showed that assortativity by participant and partner HIV status was moderate (r = 0.35).ConclusionsA high degree of population level HIV seroconcordance (both positive and negative) was observed at the time of forming new sexual partnerships. Understanding factors driving these patterns may help the development of strategies to bring the HIV epidemic under control.
Interfacing behavioral and neural circuit models for habit formation
Authors: Lerner Talia N. 
Published: January 2020

AbstractHabits are an important mechanism by which organisms can automate the control of behavior to alleviate cognitive demand. However, transitions to habitual control are risky because they lead to inflexible responding in the face of change. The question of how the brain controls transitions into habit is thus an intriguing one. How do we regulate when our repeated actions become automated? When is it advantageous or disadvantageous to release actions from cognitive control? Decades of research have identified a variety of methods for eliciting habitual responding in animal models. Progress has also been made to understand which brain areas and neural circuits control transitions into habit. Here, I discuss existing research on behavioral and neural circuit models for habit formation (with an emphasis on striatal circuits), and discuss strategies for combining information from different paradigms and levels of analysis to prompt further progress in the field.
Dietary apple polyphenols promote fat browning in high‐fat diet‐induced obese mice through activation of adenosine monophosphate‐activated protein kinase α
Authors: Zou Tiande , Wang Bo , Li Shuo , Liu Yue , You Jinming 
Published: January 2020

AbstractBACKGROUNDPromoting brown and beige adipogenesis contributes to adaptive thermogenesis, which provides a defense against obesity and related disorders. Apple polyphenols (APs) play a significant role in treating variety of metabolic diseases. This study was conducted to determine the effects of APs on the development of brown and beige adipocytes and thermogenesis and investigate whether these effects are mediated by adenosine monophosphate‐activated protein kinase (AMPK). High‐fat diet (HFD)‐induced obese mice and differentiated 3T3‐L1 adipocytes were subjected to APs treatment. The thermogenic program and associated regulatory factors, and the involvement of AMPKα was assessed.RESULTSDietary APs supplementation reduced adiposity and improved insulin sensitivity in HFD‐induced obese mice. Moreover, APs increased the oxygen consumption and heat production and decreased respiratory exchange ratio, which were accompanied by the upregulation of thermogenic genes expression and the activation of AMPKα in brown fat and inguinal white fat. Further, APs treatment directly increased expression of brown adipogenic markers and induced phosphorylation of AMPKα in differentiated 3T3‐L1 adipocytes, whereas the beneficial effects of APs were reversed by AMPK inhibition.CONCLUSIONOur results provide new insights into the function of APs in regulating brown/beige adipogenesis and adaptive thermogenesis and suggest the potential application of APs in the prevention and therapeutics of obesity and associated metabolic diseases. © 2020 Society of Chemical Industry
Prediction of starch reserves in intact and ground grapevine cane wood tissues using near‐infrared reflectance spectroscopy
Authors: Jones Joanna , Eyles Alieta , Claye Caroline , Rodemann Thomas , Dambergs Bob , Close Dugald 
Published: January 2020

AbstractBACKGROUNDNear‐infrared reflectance spectroscopy (NIRS) technology can be a powerful analytical technique for the assessment of plant starch, but generally samples need to be freeze‐dried and ground. This study investigated the feasibility of using NIRS technology to quantify starch concentration in ground and intact grapevine cane wood samples (with or without the bark layer). A partial least squares regression was used on the sample spectral data and was compared against starch analysis using a conventional wet chemistry method.RESULTSAccurate calibration models were obtained for the ground cane wood samples (n = 220), one based on 17 factors (R2 = 0.88, root mean square error of validation (RMSEV) of 0.73 mg g−1) and the other based on 10 factors (R2 = 0.85, RMSEV of 0.80 mg g−1). In contrast, the prediction of starch within intact cane wood samples was very low (R2 = 0.19). Removal of the cane bark tissues did not substantially improve the accuracy of the model (R2 = 0.34). Despite these poor correlations and low ratio of prediction to deviation values of 1.08–1.24, the root mean square error of cross‐validation (RMSECV) values were 0.75–0.86 mg g−1, indicating good predictability of the model.CONCLUSIONSAs indicated by low RMSECV values, NIRS technology has the potential to monitor grapevine starch reserves in intact cane wood samples. © 2020 Society of Chemical Industry
Effect of hydrocolloids on gel properties and protein secondary structure of silver carp surimi
Authors: Chen Jingxin , Deng Tingyue , Wang Cong , Mi Hongbo , Yi Shumin , Li Xuepeng , Li Jianrong 
Published: January 2020

AbstractBACKGROUNDHydrocolloids are the most commonly used additive in the processing of surimi products. However, the effect of hydrocolloids on surimi protein conformation has not been reported, and the level of hydrocolloids may be a key factor influencing the quality of surimi. Therefore, this study investigated the effect of curdlan, xanthan gum, κ‐carrageenan, and gelatin at various levels on gel properties and protein conformation of surimi from silver carp.RESULTSAddition of curdlan, κ‐carrageenan, or gelatin at lower level could significantly promote gel strength, textural profiles, and water holding capacity (WHC) of the surimi gels. However, gel strength and WHC gradually decreased with increasing amount of xanthan gum added. The addition of curdlan or κ‐carrageenan remarkably increased the whiteness of surimi gel, but the whiteness decreased when the concentration of κ‐carrageenan reached 5 g kg−1. Along with the increase of curdlan, κ‐carrageenan, or gelatin concentration, the index of hydrophobic interaction and hydrogen bonds first increased and then decreased, whereas index of ionic bonds first decreased and then increased. According to Raman spectroscopy data, a small content of curdlan or κ‐carrageenan promoted the conformational transition of surimi protein from α‐helix to β‐sheet, leading to the changes in gel properties of surimi gels. Scanning electron microscopy photographs showed surimi gels added with 4 g kg−1 curdlan or 2 g kg−1 κ‐carrageenan had a finer and denser network structure.CONCLUSIONCurdlan or κ‐carrageenan at an appropriate concentration is a potential modifier to effectively improve the quality of surimi products. © 2020 Society of Chemical Industry
Minimally invasive cancer surgery is associated with a lower risk of venous thromboembolic events
Authors: Krimphove Marieke J. , Reese Stephen , Chen Xi , Marchese Maya , Cone Eugene , Tully Karl H. , Paciotti Marco , Kibel Adam S. , Melnitchouk Nelya , Kluth Luis A. , Dasgupta Prokar , Trinh Quoc‐Dien 
Published: January 2020

AbstractBackgroundVenous thromboembolism (VTE) is a significant source of postoperative morbidity and mortality in patients undergoing common oncologic procedures. We sought to estimate the effect of surgical approach on the risk of developing a VTE.MethodsIBM Watson Health Marketscan Database was used to conduct this retrospective study. In total, 12 938 patients who underwent either a radical prostatectomy, partial colectomy, or hysterectomy via a minimally invasive or open approach. We used a propensity‐weighted logistic regression analysis to assess the independent effect of surgical approach on VTE. The primary outcome of interest was the 90‐day rate of VTE after surgery.ResultsPatients undergoing minimally invasive surgery across all three surgical procedures were noted to have a lower odds of developing a VTE: (radical prostatectomy, odds ratio [OR]: 0.667, 95% confidence interval [CI]: 0.500‐0.891; P = .006 |partial colectomy: OR, 0.620, 95% CI: 0.477‐0.805; P < .001| hysterectomy: OR, 0.549 95% CI: 0.353‐0.854; P = .008).ConclusionWe found that a minimally invasive approach was associated with significantly lower odds of VTE compared with undergoing the same open procedure. This study highlights how surgical approach may be an independent risk factor for development of VTE and may elucidate potential risk mitigation strategy.
Determination and comparison of agarwood from different origins by comprehensive two‐dimensional gas chromatography–quadrupole time‐of‐flight mass spectrometry
Authors: Sun Yu‐an , Zhang Hengmao , Li Zhenxing , Yu Wenhao , Zhao Zhijun , Wang Ke , Zhang Meili , Wang Jinting 
Published: January 2020

AbstractAgarwood, a species of resinous heartwood, is a precious medicinal plant and a type of rare natural spice, which is widely used in medicine, cosmetics, religious activities, and other fields. In this study, agarwood samples from eight different regions across four countries were analyzed by comprehensive two‐dimensional gas chromatography−quadrupole time‐of‐flight mass spectrometry. A total of 232 species were identified (the match factors of these compounds were above 750). The main compounds of agarwood are oxygenated sesquiterpenes and chromones. The compositions of India1 and Malaysia2 were significantly different from those of other samples, which might be attributed to the different production processes of agarwood. For further investigation, factor analysis was conducted for six agarwood samples. The results showed that the data classification possessed a regional characteristic; according to the retention time and relative content, characteristic compositions were determined by factor scores. Finally, the differences of characteristic compositions were simply analyzed, and the reasons were speculated.
Microplastic contamination in Corpus Christi Bay blue crabs,Callinectes sapidus
Authors: Waddell Elijah N. , Lascelles Nigel , Conkle Jeremy L. 
Published: January 2020

AbstractMicroplastic pollution has been observed in marine environments around the world and has the potential to negatively impact marine organisms if ingested. Blue crabs (Callinectes sapidus) are susceptible to this pollution because they feed in sediment where dense plastics accumulate. Microplastic ingestion by blue crabs was assessed in Corpus Christi Bay, TX. Crab stomachs were extracted and digested using a hydrogen‐peroxide based tissue destruction method followed by material confirmation using microattenuated total reflectance Fourier transform infrared spectroscopy (μ‐FTIR). From the 39 blue crabs sampled, 28 fully synthetic fragments and fibers and 24 semisynthetic fibers were found within their stomachs. After correcting for possible contamination, 36% of collected blue crabs contained fully synthetic fragments and fibers and semisynthetic fibers with an estimate of 0.87 items per crab. This study demonstrates the need for further studies that assess the impacts of plastic ingestion on blue crabs.
Controlled Synthesis of “Reverse Pluronic”‐Type Block Copolyethers with High Molar Masses for the Preparation of Hydrogels with Improved Mechanical Properties
Authors: Markus Felix , Bruckner Johanna R. , Naumann Stefan 
Published: January 2020

AbstractHydrogels based on Pluronics (EOn/2‐POm‐EOn/2, EO = ethylene oxide, PO = propylene oxide) have been frequently investigated, yet key limitations still remain, including a propensity for quick erosion and insufficient mechanical robustness. This issue can be alleviated by creating “reverse Pluronics” (POn/2‐EOm‐POn/2), which is proposed to enable the formation of physical cross‐links via a micellar network. Until recently, however, efforts in this direction were aggravated by synthetic difficulties, specifically prohibiting the realization of poly(propylene oxide) (PPO)‐moieties with a high DP. In this study, an organocatalytic polymerization method is employed to synthesize “reverse Pluronics,” resulting in highly defined polymers (ÐM ≤ 1.02–1.07, Mn up to 35 000 g mol−1) with exceptionally long PPO blocks. The higher molar mass and the reverse constitution of the polyether combine to enable the generation of thermoresponsive hydrogels with a storage modulus that is increased tenfold relative to reference samples. Gelation temperature and maximum storage modulus (G′max) are readily influenced by the choice of the polyether (down to 5 wt%). The improved mechanical properties are accompanied by an increased resistance toward erosion in water. Isotactic enrichment is presented as an additional tuning parameter for hydrogel properties.
Bioinspired Strategy to Reinforce Hydrogels via Cooperative Effect of Dual Physical Cross‐Linkers
Authors: Ni Xiuquan , Liang Dongran , Zhou Guanbing , Zhao Chuanzhuang , Chen Chongyi 
Published: January 2020

AbstractMany biological tissues including cartilage and tendons are composed of polymeric hydrogels, which exhibit high toughness and rapid self‐recovery. However, developing hydrogels with both high toughness and rapid recovery remains a challenge. Inspired by the nacre of abalone shell, two non‐covalent cross‐linkers (Al3+ and diethylenetriamine [DETA]) with different relaxation times are introduced into a polyacrylic acid network. Compared with mono cross‐linked hydrogels, the dual physical cross‐linked hydrogel exhibits both high toughness (work of extension at fracture up to 8.0 MJ m−3) and rapid self‐recovery ability without loss of extensibility. Strong carboxylate‐DETA ionic cross‐links with longer relaxation time endow the hydrogels with high strength and help to localize the reformation of carboxylate‐Al3+ coordinate bonds; weak carboxylate‐Al3+ coordinate bonds with shorter relaxation time dissociate and reform to dissipate energy. Therefore, the hydrogels can dissipate massive energy effectively without any residual strain. More notably, the toughness and hysteresis of hydrogels can be completely recovered in 20 min. This finding unravels a new path to reinforce the hydrogels by the cooperation of different non‐covalent interactions, which can be applied in more material systems.
Synthesis of Riboflavin‐Based Macromolecules through Low ppm ATRP in Aqueous Media
Authors: Zaborniak Izabela , Chmielarz Paweł , Matyjaszewski Krzysztof 
Published: January 2020

AbstractA vitamin‐B2‐based macroinitiator is prepared by esterification of riboflavin with 2‐bromoisobutyryl bromide. Following the “core first” methodology, “phoenix”‐shape (co)polymers with a polar riboflavin core and either a hydrophobic (poly(n‐butyl acrylate) or poly(methyl methacrylate)) or hydrophilic (poly(N‐isopropylacrylamide)‐block‐poly(oligo(ethylene glycol) acrylate) or poly(N‐isopropylacrylamide)‐block‐poly(2‐hydroxyethyl acrylate)) tails are synthesized via low ppm atom transfer radical polymerization procedures. Polymers have predetermined molecular weights and a low dispersity (Ð < 1.2). 1H NMR analysis confirms the successful formation of targeted (co)polymers with the preserved riboflavin functionality.
Regularity and continuity of commutators of the Hardy–Littlewood maximal function
Authors: Liu Feng , Xue Qingying , Zhang Pu 
Published: January 2020

AbstractLet M be the Hardy–Littlewood maximal function and let be its corresponding commutator. For and , we show that the commutator is bounded and continuous from Sobolev space to Sobolev space for when , from Triebel–Lizorkin space to if and from Besov space to if and .
Visible light‐induced synthesis of polysulfone‐based graft copolymers by a grafting from approach
Authors: Ciftci Mustafa , Tasdelen Mehmet Atilla 
Published: January 2020

ABSTRACTThe synthesis of polysulfone (PSU) graft copolymers by a two‐step “grafting from” approach is described. First, a chlorofunctional PSU (PSU‐Cl) is formed via chloromethylation of a commercial PSU. The formed polymers are used macroinitiator for the dimanganese decacarbonyl assisted free‐radical polymerization of tert‐butyl acrylate, methyl methacrylate, and styrene to give the desired graft copolymers. Moreover, amphiphilic graft copolymers are also formed via posthydrolyzation of poly(tert‐butyl acrylate) containing graft copolymers. The intermediates at various stages and the ultimate graft copolymers are characterized by various analysis techniques. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 412–416