bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ring‐Opening/Cyclization of Cyclobutanone Oxime Esters with Alkenes in Biomass‐Derived Solvent Using Copper Catalyst and Inorganic Oxidant
Authors: Zheng Yan‐Nan , Liu Yi , Cai Xue‐Er , Wu Hong‐Li , Huang Xun‐Jie , Liu Yi‐Lin , Wei Wen‐Ting 
Published: April 2022

AbstractA novel method for the ring‐opening/cyclization of cyclobutanone oxime esters with three different types of alkenes for the synthesis of valuable 2‐pyrrolidones and benzimidazo[2,1‐a]isoquinolin‐6(5H)‐ones is demonstrated for the first time, which uses CuCl as a catalyst and K2S2O8 as an oxidant in a biomass‐derived solvent 2‐methyltetrahydrofuran (2‐MeTHF). This protocol is highly efficient and gives full conversions of the substrates with good functional group compatibility. The use of economic and stable copper catalyst along with inorganic oxidant for the ring‐opening/cyclization in green solvent makes it a benign and sustainable strategy.
Simultaneously improving toughness and hydrophobic properties of cycloaliphatic epoxy resin through silicone prepolymer
Authors: Liu Yuhao , Lin Ying , Wang Yunsong , Wu Kangning , Cao Bin , Wang Liming 
Published: April 2022

AbstractTo improve the toughness and hydrophobic property of the cycloaliphatic epoxy resin (CEP), which is vital to application in high voltage insulation of outdoor transmission lines, 3‐aminopropyltriethoxysilane was used as the intermediate to prepare the silicone prepolymer by the interaction of the end groups of the CEP and the hydroxy‐terminated polydimethylsiloxane. The results showed that the silicone prepolymer segments were self‐assembled to form solid dispersion phases distributed uniformly in the CEP. The size of the dispersed phase gradually increased in CEP with more concentration of silicone prepolymer. The tensile strength and static contact angle of the CEP were simultaneously improved when content of the silicone prepolymer reached 10 phr. The tensile strength and static contact angle were mainly affected by the distribution of dispersed phase and by surface tension, respectively. With the increase of Si/C on the surface, surface tension decreased and tended to saturate. Due to small molecule migration, the CEP containing silicone prepolymer was also endowed with hydrophobic transfer properties. This paper affords a method to simultaneously enhance toughness and hydrophobic properties of CEP and deepens fundamental understanding of hydrophobic properties.
Thermoplastic polyurethane composites based on aluminum hypophosphite/modified iron tailings system with outstanding fire performance
Authors: Liu Mengru , Liu Xinliang , Sun Po , Tang Gang , Yang Yadong , Kan Yongchun , Ye Mingfu , Zong Zhifang 
Published: April 2022

AbstractIron tailings (IT) is the remaining industrial solid waste after beneficiation. The accumulation of billion tons of tailings not only occupies valuable land resources but also causes serious environmental pollution and human harm. This work aims to explore the potential application of IT in flame retardant field. The modified iron tailings (MIT) were combined with aluminum hypophosphite (AHP) to prepare a series of TPU/AHP/MIT composites by melt blending method. Thermogravimetric (TGA) test indicated that MIT and AHP significantly improved the thermal stability of the composites. The char residue of TPU/AHP22.5/MIT2.5 was enhanced to 29.60 wt% compared with 27.51 wt% of TPU/AHP25. Cone calorimetry test (CCT) confirmed that PHRR and THR of TPU/AHP15/MIT10 were decreased by 88.4% and 55.2% compared with those of pure TPU. Adding 2.5 wt% MIT could reduce the gas production of the TPU/AHP system by 32.82%. Scanning electron microscopy (SEM) and Raman spectroscopy tests confirmed that AHP/MIT system could increase the thickness and graphitization degree of char residue for the TPU composites, and thus increase the thermal stability and fire resistance of the composites. Lastly, the possible fire retarding mechanism of TPU/AHP/MIT composites was illustrated. This work provided a novel strategy for utilization of IT.
Synthesis of palladium‐chelated poly(triazine imide) heterogeneous nanocatalysts for reduction of p‐nitrophenol to p‐aminophenol
Authors: Nadizadeh Zahra , Mahdavi Hossein , Heidari Ali Akbar , Kahriz Peyman Khodaei 
Published: April 2022

AbstractIn this work, state‐of‐the‐art Pd‐chelated poly(triazine imide) (Pd‐PTI) nanocatalysts were synthesized with PTI, as cheap solid support, and different Pd contents by an easy co‐precipitation method for conducting the model reduction reaction of p‐nitrophenol to p‐aminophenol. The electron microscopy observations (i.e., scanning electron microscopy and transmission electron microscopy), quantitative dispersive X‐ray spectroscopy and elemental mapping images demonstrated that Pd nanoparticles (NPs) were homogeneously loaded on the surface of highly crystalline two‐dimensional (2‐D) PTI nanosheets. Among the all prepared Pd‐PTI nanocatalysts, the PTI‐1500‐Pd indicated the highest pseudo‐first‐order rate constant of 12.7 × 10−3 s−1, which was significantly higher than that of the recently reported Pd‐based nanocatalysts. This catalyst showed ultrahigh, superior catalytic efficiency (≥99%) and stability properties for the hydrogenation of p‐nitrophenol within 40 s under mild conditions and possessed excellent recovery (≥90%) of expensive Pd NPs after five consecutive cycles. The high‐catalytic performance of the PTI‐1500‐Pd nanocatalyst is related to specific properties of the highly crystalline structure, high‐surface area and very available surface amine groups of 2‐D PTI nanosheets, which functioned as an active site for immobilizing ultrafine Pd0 NPs.
Rheological behavior of poly(propylene) reinforced with graphene nanoplatelets for injection molding
Authors: Melo de Lima Luiza R. , Magalhães da Silva Sara P. , Trindade Tito , Oliveira José M. 
Published: April 2022

AbstractPoly(propylene) (PP)‐based graphene nanoplatelets (GnPs) nanocomposites are processed by a melt blending technique. To obtain more knowledge about the rheological behavior of nanocomposites for injection molding, the rheological characterization of nanocomposites is performed using a double capillary rheometer over a shear rate range from 10 to 6000 s−1. The influence of processing temperature (170, 180, and 190°C) is evaluated. To improve the interaction between PP and GnPs, maleic anhydride (MA) is applied as a compatibilizer. The viscosity master curves are fitted to the Cross‐WLF model. In relation to neat PP, the presence of GnPs promote a viscosity decrease. The nanocomposites containing MA exhibit a higher viscosity than the non‐compatibilized counterparts, suggesting adhesion improvement between PP and GnPs. In addition to the MA compatibilizer effect, the results show that its presence could act as a plasticizer/lubricant in the PP matrix. The morphology characterization of nanocomposites suggests that in addition to improving the adhesion between PP and GnPs, the MA presence also improved the GnPs dispersion in the PP matrix. The presence of GnPs and MA can affect the Newtonian behavior of the PP matrix. All studied samples reveal thermo‐rheological simplicity and pseudo‐plastic behavior.
The illumination effects on the current conduction mechanisms of the Au/(Er2O3:PVC)/n‐Si (MPS) Schottky diodes
Authors: Altındal Şemsettin , Azizian‐Kalandaragh Yashar , Ulusoy Murat , Pirgholi‐Givi Gholamreza 
Published: April 2022

AbstractPhotoresponse of the Au/(Er2O3:PVC)/n‐Si diode was executed in a wide range of illumination intensity (P). Its basic electrical parameters such as ideality factor (n), barrier height (ΦB0), series and shunt resistances (Rs, Rsh), photocurrent (Iph), energy‐dependence of interface states (Nss), and photosensitivity (S) were calculated from the results of the current–voltage (I–V) measurements. At the negative‐bias region, an increase in Iph is observed due to the e−‐h+ pairs that occur as a result of increasing P and their drift in opposite directions under the internal electric field. The ln(Iph)–ln(P) plot shows a good linear behavior under various applied voltages. Their slopes vary from 1.47 to 1.64, indicating that empty trap levels, that is, levels not occupied by charges, are of low density. The values n, ΦB0, and Rs were obtained using the thermionic emission theory, Cheung, and Norde functions. The value of ΦB0 decreases with increasing n and P as linearly with ΦB0(n) = (−0.143n + 1.118) eV and ΦB0(P) = (−2 × 10−4P + 0.831) eV, respectively. This illumination coefficient of ΦB0 (=−2 × 10−4 eV/[mW/cm2]) is close to the temperature coefficient bandgap of Si (=−4.73 × 10−4 eV/K). These results show that the performed Au/(Er2O3:PVC)/n‐Si diode has excellent photo‐response and can be successfully used in photovoltaic applications instead of conventional metal–semiconductor diodes.
Effect of graphite nanoplatelets surface area on mechanical properties of room‐temperature vulcanized silicone rubber nanocomposites
Authors: Kumar Vineet , Kumar Anuj , Alam Md. Najib , Park Sang‐Shin 
Published: April 2022

AbstractGraphite nanoplatelet (GNP) flakes have attracted attention for the production of polymeric nanocomposites owing to their excellent mechanical, thermal, and electrical properties. In this work, the impact of three grades of GNP flakes with different surface area on the properties of room‐temperature vulcanized silicone rubber (RTV‐SR) nanocomposites was analyzed. The surface area was determined by the Brunauer–Emmett–Teller (BET) method using N2 adsorption isotherms. The BET analysis showed that the GNP grades had BET surface areas of 422, 295, and 123 m2/g. Nanocomposites based on the three grades of GNP flakes with different surface area and RTV‐SR were prepared using the solution‐casting process. Mechanical analysis of the samples showed that the compressive modulus increased from 3.8 MPa (0 phr) to 4.4, 4.34, and 5.26 MPa at the filler loading of 15 phr of GNPs with 422, 295, and 123 m2/g, respectively. In addition, the fracture strain of the nanocomposites increased from 116% (0 phr) to 228%, 198%, and 151% in the samples with 422, 295, and 123 m2/g, respectively, at the filler loading of 15 phr GNP.
Synthesis, properties, and hydrolysis of bio‐based poly(butylene succinate‐co‐diethylene glycol succinate) copolyesters
Authors: Ding Yue , Li Shilin , Wang Jingxi , Liu Yuanyuan , Dong Liming , Du Xihua , Huang Dan , Ai Tianhao , Ji Junhui 
Published: April 2022

AbstractMicroplastic has become the focus of environmental pollution recently, especially in seawater. Due to its high crystallinity and hydrophobicity, the degradation rate of poly(butylene succinate) (PBS) is slow. In this paper, a series of poly(butylene succinate‐co‐diethylene glycol succinate) (PBSD) copolymers were synthesized by melt‐polycondensation in order to improve the nonenzymatic hydrolysis of PBS. The contact angle and water uptake content of copolymer were increased obviously when the regular crystalline structure of chain segment was disturbed by diethylene glycol. Rheological tests revealed the microphase separation structure occurred at 130°C. The tensile strength of PBSD40 copolymer was 15 MPa and the elongation at break was more than 700%, and the decomposition temperature was above 370°C. The weight loss of PBSD60 copolymer in acid condition was 98.6% after 49 days at 50°C. However, in neutral condition and simulated seawater, the weight loss was less than 10%. Acid and alkaline catalyzed the hydrolysis of ester bonds. Some holes and cracks appeared at the surface of the samples after degradation from SEM analysis. Thus, PBSD copolymers have the potential to serve as promising water degradable materials.
High‐performance thermoplastic polyureas via a non‐isocyanate route from urea and aliphatic diamines
Authors: Lin Chenxi , Xie Kangzhou , Tang Donglin 
Published: May 2022

AbstractPolyureas (PUrs) with excellent properties have been applied widely in many fields. These days attention has been turned to non‐isocyanate routes for PUr preparation due to the toxicity and the high cost of isocyanates. Urea is a green chemcial which can be either from urine or from recycled carbon dioxide and ammonia. Here we introduce a urea‐based route to prepare PUrs, by melt polycondensation of urea and 1,10‐diaminodecane (DA‐10) or/and 1,6‐diaminohexane (DA‐6) without catalyst, solvent, and high pressure. It is difficult to synthesize such thermoplastic PUrs from diisocyanate without any solvent since the melting point of PUr is normally higher than 170°C at which isocyanate is able to react with urea group to form biuret. The thermoplastic PUrs obtained in this study exhibit excellent mechanical and thermal properties. Furthermore, the properties can be adjusted by changing the feed ratio of diamines (DA‐6/DA‐10). The compression‐molded PUrs show even better mechanical properties than ultra‐high molecular weight polyethylene (UHMWPE). The values of Young's modulus, strength at break and elongation at break are found to be 230–300 MPa, 40–60 MPa and 200%–400%, respectively (except for PUr‐6). Therefore, this facile, non‐isocyanate approach provides a viable alternative to the current industrial process for high‐performance PUrs.
Distance from home to birth hospital, transfer, and mortality in neonates with hypoplastic left heart syndrome in California
Authors: Purkey Neha J. , Ma Chen , Lee Henry C. , Hintz Susan R. , Shaw Gary M. , McElhinney Doff B. , Carmichael Suzan L. 
Published: April 2022

AbstractBackgroundPrior studies report a lower risk of mortality among neonates with hypoplastic left heart syndrome (HLHS) who are born at a cardiac surgical center, but many neonates with HLHS are born elsewhere and transferred for repair. We investigated the associations between the distance from maternal home to birth hospital, the need for transfer after birth, sociodemographic factors, and mortality in infants with HLHS in California from 2006 to 2011.MethodsWe used linked data from two statewide databases to identify neonates for this study. Three groups were included in the analysis: “lived close/not transferred,” “lived close/transferred,” and “lived far/not transferred.” We defined “lived close” versus “lived far” as 11 miles, the median distance from maternal residence to birth hospital. Log‐binomial regression models were used to identify the association between sociodemographic variables, distance to birth hospital and transfer. Cox proportional hazards models were used to identify the association between mortality and distance to birth hospital and transfer. Models were adjusted for sociodemographic variables.ResultsInfants in the lived close/not transferred and the lived close/transferred groups (vs. the lived far/not transferred group) were more likely to live in census tracts above the 75th percentile for poverty with relative risks 1.94 (95% confidence interval [CI] 1.41–2.68) and 1.21 (95% CI 1.05–1.40), respectively. Neonatal mortality was higher among the lived close/not transferred group compared with the lived far/not transferred group (hazard ratio 1.77, 95% CI 1.17–2.67).ConclusionsInfants born to mothers experiencing poverty were more likely to be born close to home. Infants with HLHS who were born close to home and not transferred to a cardiac center had a higher risk of neonatal mortality than infants who were delivered far from home and not transferred. Future studies should identify the barriers to delivery at a cardiac center for mothers experiencing poverty.
Biosynthesis of allantoin in Escherichia coli via screening a highly effective urate oxidase
Authors: Zhang Fengjuan , Sun Xinxiao , Shen Xiaolin , Yan Yajun , Wang Jia , Yuan Qipeng 
Published: April 2022

AbstractAllantoin is an important fine chemical that can be widely used in pharmaceutical, cosmetic and agricultural industries. Currently, allantoin is mainly produced by plant extraction or chemical synthesis. Due to the cost and environmental concerns, biosynthesis of allantoin from renewable feedstock is much more desirable. However, microbial production of allantoin from simple carbon sources has not yet been achieved so far. In this study, de novo biosynthesis of allantoin was achieved by constructing an artificial biosynthetic pathway. First, screening of efficient urate oxidases and xanthine dehydrogenases enabled allantoin production from hypoxanthine, a natural intermediate in purine metabolic pathway in Escherichia coli. Then, assemble of the entire pathway resulted in 13.9 mg/L allantoin from glucose in shake flask experiments. The titer was further improved to 639.8 mg/L by enhancing the supply of the precursor, redistribution of carbon flux, and reduction of acetate. Finally, scale‐up production of allantoin was conducted in a 1‐L fermentor under fed‐batch culture conditions, which enabled the synthesis of 2360 mg/L allantoin, representing a 170‐fold increase compared with the initial strain. This study not only demonstrates the potential for industrial production of allantoin, but also provides a bacterial platform for synthesis of other purines‐derived high‐value chemicals.
Motivations and identities of “grassroots” circular entrepreneurs: An initial exploration
Authors: Henry Marvin , Hoogenstrijd Thijs , Kirchherr Julian 
Published: April 2022

AbstractThe circular economy (CE) is now widely seen as a key concept to drive sustainability transformations. Existing research on circular business models has tentatively indicated that circular entrepreneurship may be able to play a pivotal role in the transition process. However, grassroots activity in CE has not yet received substantive scholarly attention, nor have the founders of circular ventures. This study attempts to start closing this gap by presenting the first empirical analysis of circular founders' motivations and identities. Our work is based on interviews with 57 founders of circular start‐ups in Europe and Australia. The analysis reveals distinct characteristics for these entrepreneurs. We find that noneconomic motives are dominant drivers of grassroots circular entrepreneurs while they include a triple bottom line orientation (i.e., economic, social, and environmental value) in principle. Yet, circular start‐up founders barely formalize socio‐political dimensions in their activities despite being motivated by social altruism. Furthermore, circular founders have an inventive mindset when starting their entrepreneurial journey, possibly driven by their limited market‐oriented positioning, limited entrepreneurial experience, and managerial education. However, their scaling ambitions grow significantly over time, as opposed to social and sustainable entrepreneurs. Overall, our findings suggest adding grassroots circular entrepreneurs or circular founders as a distinct group of sustainability entrepreneurs to the scientific discourse on sustainability‐motivated entrepreneurship and circular innovation studies.
Bifid median nerve as an anatomical risk factor for carpal tunnel syndrome: A meta‐analysis
Authors: Asghar Adil , Patra Apurba , Satish Ravi Kumar , Tubbs R. Shane , Kumar Ashutosh , Naaz Shagufta 
Published: April 2022

AbstractAs the median nerve enters the carpal tunnel, it is a single nerve that soon bifurcates into lateral and medial branches into the hand. If the bifurcation is proximal to the carpel tunnel, a bifid median nerve (BMN) results. Carpal tunnel syndrome is often associated with a BMN with or without a persistent median artery. Individual keywords and MeSH phrases were searched in the Google Scholar, SCOPUS, and PubMed databases. Full texts were then collected and assessed for suitability. The prevalence of BMN at the wrist joint in normal and carpal tunnel syndrome wrists (precanal part) and the mean difference between groups were recorded. Only human data were used to test the findings. The pooled odds ratio (with minimal heterogeneity) was 1.50 [1.17–1.93, 95% CI]. The BMN cross‐sectional area (CSA) was significantly greater than that of a solitary median nerve in normal wrists. The mean difference in CSA between the two was 1.50 mm2[0.56–2.45 mm2, 95% CI] without heterogeneity (i2 = 0). Sex and laterality distributions scarcely differed between the two types of wrists. Owing to the insufficiency of data, the relationships with mean height and weight were not examined. There was a 50% greater incidence of bifid median nerves in carpal tunnel syndrome patients than in normal subjects. A bifid median nerve increases the mean CSA at the wrist joint by 1.5 mm2. These findings indicate that the bifid median nerve is an anatomical risk factor for carpal tunnel syndrome.
A novel prognostic nomogram for patients with extragastric mucosa‐associated lymphoid tissue lymphoma: A multicenter study
Authors: Li Xiaoqian , Hong Huangming , Huang He , Zou Liqun , Chen Zegeng , Zhang Zhihui , Zhang Liling , Fang Xiaojie , Guo Hongqiang , Xie Ke , Tian Ying , Lin Suxia , Chen Yungchang , Zhang Wei , Yao Yuyi , Pan Fei , Weng Huawei , Lin Tongyu 
Published: April 2022

AbstractBackgroundThe aim of this study was to explore predictors and construct a nomogram for risk stratification in primary extragastric mucosa‐associated lymphoid tissue (MALT) lymphoma.MethodsExtragastric MALT lymphoma cases newly diagnosed between November 2010 and April 2020 were assessed to construct a progression‐free survival (PFS)‐related nomogram. We also performed external validation of the nomogram in an independent cohort.ResultsWe performed multivariate analyses of 174 patients from 3 hospitals who were included in the training cohort. Stage, hepatitis B virus surface antigen (HBsAg) status, and Ki67 expression were significantly associated with PFS. These three factors were used to construct a nomogram, which was shown to have a C‐index of 0.89. Two risk groups (low risk and high risk) were identified by the prognostic model. The 5‐year PFS was 98.9% for the low‐risk group and 69.3% for the high‐risk group (p < 0.001). The overall survival (OS) could also be effectively distinguished by the nomogram, resulting in an OS of 100% for the low‐risk group and 94.6% for the high‐risk group (p = 0.01). These results were validated and confirmed in an independent cohort with 165 patients from another three hospitals. The 5‐year PFS rates were 94.8% and 66.7% for the low‐risk and high‐risk groups, respectively (p < 0.001). The 5‐year OS rates were 97.9% and 88.4%, respectively (p = 0.016).ConclusionThe nomogram could well distinguish the prognosis of low‐ and high‐risk patients with extragastric MALT lymphoma and is thus recommended for clinical use.