bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retracted: Facile synthesis of two oxocan derivatives using some chemical strategies
Authors: Lauro Figueroa‐Valverde , Francisco Diaz Cedillo , Marcela Rosas‐Nexticapa , Maria Lopez‐Ramos , Virginia Mateu‐Armand , Alejandra Garcimarero‐Espino E. , Yazmin Ortiz‐Ake 
Published: November 2020

AbstractThere are several studies for the synthesis of oxacycle derivatives using some reagents which require special conditions have been reported. The aim of this study was to synthesize two oxocan derivatives from either imidazole or 2‐methylimidazole. The chemical structure was evaluated through both 1H NMR and 13C NMR spectroscopic analysis. The results showed a moderate yielding from oxocan derivatives. It should be mentioned that reagents used in this investigation are not expensive and do not require special conditions for handling.
Umbilical cord blood cells for the treatment of preterm white matter injury: Potential effects and treatment options
Authors: Qiu Han , Qian Tianyang , Wu Tong , Wang Xiaoyang , Zhu Changlian , Chen Chao , Wang Laishuan 
Published: November 2020

AbstractPreterm birth is a global public health problem. A large number of preterm infants survive with preterm white matter injury (PWMI), which leads to neurological deficits, and has multifaceted etiology, clinical course, monitoring, and outcomes. The principal upstream insults leading to PWMI initiation are hypoxia‐ischemia and infection and/or inflammation and the key target cells are late oligodendrocyte precursor cells. Current PWMI treatments are mainly supportive, and thus have little effect in terms of protecting the immature brain or repairing injury to improve long‐term outcomes. Umbilical cord blood (UCB) cells comprise abundant immunomodulatory and stem cells, which have the potential to reduce brain injury, mainly due to anti‐inflammatory and immunomodulatory mechanisms, and also through their release of neurotrophic or growth factors to promote endogenous neurogenesis. In this review, we briefly summarize PWMI pathogenesis and pathophysiology, and the specific properties of different cell types in UCB. We further explore the potential mechanism by which UCB can be used to treat PWMI, and discuss the advantages of and potential issues related to UCB cell therapy. Finally, we suggest potential future studies of UCB cell therapy in preterm infants.
A Novel Temperature‐Dependent Hydrogel Emulsion with Sol/Gel Reversible Phase Transition Behavior Based on Polystyrene‐co‐poly(N‐isopropylacrylamide)/Poly(N‐isopropylacrylamide) Core–Shell Nanoparticle
Authors: Jiang Yingnan , Yan Ruyue , Pang Bo , Mi Jiqiang , Zhang Yang , Liu Hou , Xin Jingwei , Zhang Ying , Li Na , Zhao Yu , Lin Quan 
Published: November 2020

AbstractAs a kind of temperature‐responsive hydrogel, polystyrene‐co‐poly(N‐isopropylacrylamide)/poly(N‐isopropylacrylamide) (PS‐co‐PNIPAM/PNIPAM) core–shell nanoparticles prepared by two‐step copolymerization are widely studied and used because of their specific structures and properties. Unlike most reports about the steady stability of PS‐co‐PNIPAM/PNIPAM core–shell nanoparticle hydrogel emulsion, in this work, the PS‐co‐PNIPAM/PNIPAM core–shell nanoparticle hydrogel emulsion (symbolized as PS/PNIPAM hydrogel emulsion), which is prepared after the second step of synthesis and without washing out a large number of PNIPAM polymer segments, shows a reversible temperature‐dependent sol–gel transition characteristic during the temperature range of 34–80 °C. The PS/PNIPAM hydrogel emulsion is a normal solution at room temperature, and it changes from a sol to a gel statue when the temperature approaches up to low critical solution temperature (LCST). As the temperature continues to increase, the gel (core–shell nanoparticles as the crosslinkers and the linear PNIPAM chain as the 3D gel network) of the PS/PNIPAM hydrogel emulsion gradually shrinks and drains linearly. Compared with most crosslinked hydrogels, the hydrogel here can be arbitrarily changed in shape according to use needs, which is convenient for use, transportation, and storage. Here a new route is provided for the preparation of a PS/PNIPAM core–shell hydrogel nanoparticle system, as well as a new supramolecular crosslinking sol–gel system for application in biomedical materials, sensors, biological separation, drug release, macromolecular adsorption, and purification.
Quantitative transport mapping (QTM) of the kidney with an approximate microvascular network
Authors: Zhou Liangdong , Zhang Qihao , Spincemaille Pascal , Nguyen Thanh D. , Morgan John , Dai Weiying , Li Yi , Gupta Ajay , Prince Martin R. , Wang Yi 
Published: November 2020

PurposeProof‐of‐concept study of mapping renal blood flow vector field according to the inverse solution to a mass transport model of time resolved tracer‐labeled MRI data.Theory and MethodsTo determine tissue perfusion according to the underlying physics of spatiotemporal tracer concentration variation, the mass transport equation is integrated over a voxel with an approximate microvascular network for fitting time‐resolved tracer imaging data. The inverse solution to the voxelized transport equation provides the blood flow vector field, which is referred to as quantitative transport mapping (QTM). A numerical microvascular network modeling the kidney with computational fluid dynamics reference was used to verify the accuracy of QTM and the current Kety’s method that uses a global arterial input function. Multiple post‐label delay arterial spin labeling (ASL) of the kidney on seven subjects was used to assess QTM in vivo feasibility.ResultsAgainst the ground truth in the numerical model, the error in flow estimated by QTM (18.6%) was smaller than that in Kety’s method (45.7%, 2.5‐fold reduction). The in vivo kidney perfusion quantification by QTM (cortex: 443 ± 58 mL/100 g/min and medulla: 190 ± 90 mL/100 g/min) was in the range of that by Kety’s method (482 ± 51 mL/100 g/min in the cortex and 242 ± 73 mL/100 g/min in the medulla), and QTM provided better flow homogeneity in the cortex region.ConclusionsQTM flow velocity mapping is feasible from multi‐delay ASL MRI data based on inverting the transport equation. In a numerical simulation, QTM with deconvolution in space and time provided more accurate perfusion quantification than Kety’s method with deconvolution in time only.
Professional development participation by teachers facilitated student exposure to agriculture
Authors: Lindsey Alexander J. 
Published: November 2020

AbstractThe use of modern technological advances to aid with agricultural production has led to many new career opportunities in the agricultural industry especially for those with strong science, technology, engineering, and math (STEM) training. However, limited exposure to agricultural content in middle and high school education may affect how many students enter the industry. Professional development sessions and post‐session surveys for teachers were designed to raise teacher awareness of careers in agriculture and current agricultural facts, quantify use of professional development materials in the classroom, and measure change in behavior of teachers and student perceptions in response to participation. Four professional development sessions were offered from 2017 to 2019 for teachers of grades 6–12. Sessions consisted of presentations, hands‐on activities, and reflection and discussion on topics related to technology in agriculture. Although direct knowledge of agricultural facts did not increase (P = .2), teacher comfort in teaching about technology in agriculture and career opportunities did increase both in the short term and long term (P < .02). Curriculum related to nitrogen cycling and soil properties were most widely used, and 90% of survey respondents reported positive changes in student perceptions of careers in agriculture. These results suggest the professional development sessions were effective at enabling teachers to teach on these subjects, and student perceptions were positively impacted from teachers participating in the sessions.
Interaction of metformin hydrochloride with ionic surfactants in aqueous and NaCl solution: Effect of temperatures and compositions
Authors: Hoque Md. Anamul , Alam Md. Masud , Khan Mohammed Abdullah , Kumar Dileep , Khan Javed Masood , Malik Ajamaluddin , Ahmed Mohammad Z. , Ahamed Anwar 
Published: November 2020

AbstractHerein, the interaction of metformin hydrochloride (MNH) with cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) has been investigated by the conductometric technique in aqueous medium as well as in the existence of NaCl over a range of temperatures. MNH, an antidiabetic drug that belongs to the biguanide group, is generally prescribed for the patients to manage type II diabetes. The micellar parameters such as critical micelle concentration (CMC), the extent of counterion binding (β), and different thermodynamic properties for MNH + surfactant systems were estimated and discussed elaborately. The CMC values of CTAB + MNH and SDS + MNH systems are dependent on the concentrations of NaCl at different temperatures. The significant decrease of CMC values in NaCl solution indicates that NaCl stabilizes MNH‐mediated surfactant micelles. The CMC values versus T plots show a nonlinear pattern for the CTAB + MNH system, whereas the CMC values almost monotonically decrease with increasing temperature for the SDS + MNH system. The values of ∆G0m were negative for both systems in all cases. Both ∆G0m and ∆G0m,t values indicate that the aggregation processes of MNH + surfactants mixture are spontaneous, which is also manifested in NaCl solution and with the change of temperatures in most of the cases. The obtained results proposed that surfactants may assist as a proficient drug delivery agent for antidiabetic drug, enhancing their bioavailability.
Pathway to excellence in cancer care: learning from Qatar's experience
Authors: Qoronfleh M. Walid 
Published: November 2020

AbstractIn 2011, Qatar launched the First National Cancer Control Program in the GCC. The National Cancer Strategy, A Path to Excellence (2011‐2016) and the companion document, Qatar National Cancer Research Strategy (2012) transformed cancer care in Qatar. Cancer outcomes are now equivalent to countries with long established National Cancer Strategies (The Lancet, 2018). Critical to the success were robust governance structures, informed and committed leadership, comprehensive involvement of all sectors including public and private providers, charities, private sector employers, academic partners and the judicious use of expert groups and subject matter experts. Major milestones have been reached in the prevention, early detection, treatment and care of cancer throughout the period the National Cancer Strategy has been in place. Achievements have included harmonized multi‐sectoral awareness, education, and myth busting campaigns aligned to a single National Awareness Calendar. A National Breast Cancer Screening Program, a National Bowel Cancer Screening Program and an opportunistically ran Cervical Cancer Screening Program have been established, supported by a dedicated Cancer Screening Call Center and a Mobile Screening Unit for those hard to reach geographical areas in Qatar. Internationally peer reviewed cancer specific teams included new and extended roles, the introduction of forefront diagnostic and treatment modalities and a patient centered approach to the organization of care have improved clinical outcomes, patient experience, and public confidence. Future development will focus on consolidating areas of significant achievement incorporating emerging evidence and new technologies. This will include evidence‐based approaches for public engagement, prevention and early detection, particularly the use of personalized approaches. As with any successful cancer program, survivorship and transition programs need to be enhanced to include chronic illness and palliative care models. Rare cancers, further development of local faculty and maturity of Qatar's high impact Cancer Research portfolio are also a focus. Qatar provides a model that illustrates how the principles of good cancer control are internationally applicable but need to be locally owned and adapted to the country and be culturally specific. It is critical to have clear leadership and governance, as well as the right people in all partner organizations to work collaboratively in achieving a common goal. We make key policy recommendations that are applicable inside and outside of Qatar. Moreover, we share the successful cancer care framework learned from the Qatar experience.
Crystal structure of the large subunit of cobaltochelatase from Mycobacterium tuberculosis
Authors: Zhang Jia‐Hui , Yuan Hui , Wang Xiao , Dai Huai‐En , Zhang Min , Liu Lin 
Published: November 2020

AbstractCobaltochelatase in aerobic cobalamin biosynthesis is a complex composed of three subunits. The large subunit CobN is a 140‐kDa protein and is homologous to the ChlH subunit of magnesium chelatase. Previously we have reported the 2.5‐Å structure of a cyanobacterial ChlH. Here we present the 1.8‐Å structure of CobN from Mycobacterium tuberculosis. The overall structure of CobN and ChlH is similar, but significant difference occurs in the head domain. Structural comparison of domains between the two proteins unravels candidate regions for substrate binding and helps to locate a triad of residues that may be essential for metal ion binding.
Control of the Half‐Skyrmion Hall Effect and Its Application to Adder–Subtractor
Authors: Yang Seungmo , Moon Kyoung‐Woong , Kim Changsoo , Kim Duck‐Ho , Shin Jeonghun , Hong Jinpyo , Kim Se Kwon , Hwang Chanyong 
Published: November 2020

AbstractSkyrmions have attracted a great attention in spintronics because of their potential use as robust information carriers with distinctive protection. Though the realization of skyrmion‐based devices requires flexible control of a skyrmion motion, achieving such a skyrmion motion has been hampered by the skyrmion Hall effect (SkHE), which refers to the presence of a finite angle between a current and the skyrmion trajectory. Here, new insight for the precise control of half‐skyrmion motion is presented, including complete suppression of the SkHE by deforming the internal structure of skyrmions, which is experimentally achieved by external magnetic field to steer current‐driven half‐skyrmions in the desired direction. Furthermore, based on the unique advantages in half‐skyrmions, the potential of half‐skyrmions application beyond skyrmion‐based electronics is also demonstrated by presenting simple half‐skyrmion‐based addition/subtraction operation. The findings of controllability of 2D half‐skyrmion motion will provide new perspectives on utilization of topological solitons for device applications.
Do IPO costs affect innovation?
Authors: Cox Justin , Fuller Kathleen P. , Lin Zhilu , Wu Wentao 
Published: November 2020

AbstractGiven the importance of accessing capital to a firm's future, we analyze whether the initial public offering (IPO) costs impact the firm's future innovation. Using the firm's patents and patent citations as our measures of innovation, results indicate that firms with higher IPO costs experience lower initial post‐IPO firm innovation. We also document that the relation between IPO costs and initial post‐IPO firm innovation is stronger in financially constrained firms. Results hold across multiple measures of IPO costs as well as controlling for the level of pre‐IPO innovation activity. We conclude that IPO costs are an important determinant of short‐term post‐IPO firm innovation.
Determination of Mercury Ions in Aqueous Medium and Urine Sample Using Thiocarbohydrazide Based Sensor
Authors: Kumar Ashok , Kumar Davinder , Chhibber Manmohan 
Published: November 2020

AbstractThe identification and quantification of toxic Hg2+ ions in biological fluids is significant due to its harmful effects. The ion is an exceptional contaminant due to its manifestation in the environment through anthropogenic emissions besides other industrial processes. The bioaccumulation of Hg2+ ions through water bodies, soil and food causes damage to the central nervous system and endocrine glands. This work describes the synthesis of Compd‐2 (Compound 2), a thiocarbohydrazide‐based UV‐active sensor, that can detect Hg2+ and Cu2+ ions in the aqueous medium (HEPES buffer (3 mM) /acetonitrile = 99 : 1, v/v ). Compd‐2 responds linearly to the varying concentrations of Hg2+ with a minimum detection limit of 27 nM and a 1 : 1 stoichiometry. 1H NMR titration with increasing Hg2+ ion concentrations confirmed its interaction by shifting of the peak. In‐silico modelling using Gaussian 16.0 and IR spectroscopy verified a single binding site for the Hg2+ ions. Aqueous solubility of Compd‐2 was used as an advantage to develop a methodology for the detection and quantification of Hg2+ ions in the human urine sample. The work also demonstrates the nM quantification of Hg2+ ions in the urine sample by the standard addition method.
Zinc and Cadmium Nitrilotris(methylenephosphonate)s: A Comparative Study of Different Coordination Structures for Corrosion Inhibition of Steels in Neutral Aqueous Media
Authors: Chausov Feodor F. , Kazantseva Irina S. , Reshetnikov Sergey M. , Lomova Natalya V. , Maratkanova Alyona N. , Somov Nikolay V. 
Published: November 2020

AbstractThe paper gives a comparative analysis between different coordination structures, determined by single crystal XRD, of Zn and Cd NTP complexes used as corrosion inhibitors for steels in aqueous media according to voltammetry data. The paper provides the results for polymeric O‐coordinated complexes and mononuclear N,O‐coordinated complexes of both metals. Structural differences between complexes of the same metal which possess different structures (polymeric and mononuclear) lead to their different anti‐corrosion activity. Polymeric O‐coordinated complexes of both metals exhibit low anti‐corrosion activity. N,O‐coordinated complexes of Zn and Cd are effective corrosion inhibitors, with Cd complex being four times more effective than Zn complexes.
A Novel High Selective Colorimetric Chemosensor for Determination of Copper in Food Samples: Visual Detection
Authors: Mohammadnejad Masoumeh , Shiri Morteza , Heydari Masumeh , Faghihi Zeinab , Afshinpoor Leila 
Published: November 2020

AbstractRhodamine B hydrazide and 2‐chloroquinoline‐3‐carbaldehyde derivatives were used to synthesize novel colorimetric sensors for highly selective detection of copper ion. The measurement was based on the interaction between the synthesized ligands and Cu2+ and the sharp color change of the ligand from yellow to pink in the presence of Cu2+. Increase in absorbance intensity at the new appeared absorbance peak was used as an analytical signal. The effect of parameters, such as time and sensor concentration were also investigated and discussed. The calibration curve was considered too under the optimum experimental conditions and was linear in the range 0.05–5.00 μg mL−1 with a limit of detection 0.016 μg mL−1. The interferences of some common ions were studied and the synthetic ligand was found to be a high selective sensor. Selectivity of the proposed method makes it as an applicable technique for the determination of copper in foodstuff samples.
A Three‐Dimensional Pentanuclear Co(II) Coordination Polymer: Structural Topology, Hirshfeld Surface Analysis and Magnetic Properties
Authors: Kamaal Saima , Gupta Mayak , Mishra Rupali , Ali Arif , Alarifi Abdullah , Afzal Mohd , Das Raja , Ahmad Musheer 
Published: November 2020

AbstractA 3D pentanuclear coordination polymer of Co(II); {[Co5(L2‐)4(HL‐)2(bpmp)2 (H2O)2].(H2O)5}n (CP1) was synthesized by the self‐assembly of semi‐flexible 5‐benzylamino‐isophthalic acid (H2L) and N‐donor auxiliary ligand 1,4‐bis(4‐pyridinylmethyl)piperazine (bpmp) using Co(NO3)2 ⋅ 6H2O under hydrothermal condition. The CP1 has been structurally characterized by elemental analysis, TGA, Powder‐XRD and IR spectroscopy which was further corroborated by single crystal X‐ray studies. Structurally, it is a 3D pentanuclear cobalt cluster secondary building units (SBUs) which are formed by carboxylates oxygen of H2L and nitrogen of bpmp. The topological analysis revealed that CP1 possesses a 2‐nodal 5,6‐connected three‐dimensional (3D) coordination framework with pcu net. Variable temperature magnetic measurements demonstrate that CP1 shows antiferromagnetic behavior.
A Systematic Study of the Stability of Enzyme/Zeolitic Imidazolate Framework‐8 Composites in Various Biologically Relevant Solutions
Authors: Gao Yuan , Doherty Cara M. , Mulet Xavier 
Published: November 2020

AbstractMetal organic frameworks (MOFs) have been used to encapsulate numerous enzymes. This study has encapsulated two enzymes in zeolitic imidazolate framework‐8 (ZIF‐8) and examined the structural stability of the enzyme@ZIF‐8 composites in solutions of various biologically relevant agents (i. e. amino acids, proteins, organic acids, organic/inorganic buffers, surfactants, polymers, carbohydrates and salts). Many of the agents were found to completely dissolve the composites or severely damage their structural integrity, causing the release of the enzymes from the composites. These agents plausibly exerted their destabilizing effects on the composites by interactions with zinc or by complexation with the enzymes in the enzyme@ZIF‐8 composites. Notably, Tris and HEPES buffers were found to be supportive of the composites in the short term. The results show the need to improve the stability of the enzyme@ZIF‐8 systems for certain applications and suggest triggered release of the encapsulated biomolecules from the porous matrix.
Sonophotocatalytic Degradation of Pollutants by ZnO‐Based Catalysts: A Review
Authors: Asli Sahebeh Alizadeh , Taghizadeh Majid 
Published: November 2020

AbstractSonophotocatalyticprocess (SPC) is the simultaneous use of ultraviolet radiation (UV), ultrasonic radiation (US), and semiconductor materials as photocatalysts and sonocatalysts for the generation of reactive oxygen species (ROS). These free radicals oxidize several pollutant molecules in various industrial wastewaters. The objective of this review was to compare the papers published on the sonophotocatalytic degradation of different pollutants in the presence of zinc oxide‐based particles. The elimination rate of contaminants in this process was compared with individual methods such as sonocatalysis and photocatalysis. The experimental conditions, including the catalyst dosage, the pollutant concentration, the radiation power, the applied frequency, the initial pH, and the reaction time were further investigated. ZnO nanoparticles are well‐known as semiconductor materials with good sonophotocatalytic activity. In general, sonophotocatalysis is emerging as one of the most efficient treatment techniques for degrading the recalcitrant pollutants in the aqueous medium. It is expected that these technologies result in more progressive research with the most degradation efficiency.
MOFs Derived Catalysts Prepared by Pyrolysis for Hydrogenation of Bio‐Based Furfural: A Mini‐Review
Authors: Zhao Mei‐Xia , Yang Ning , Li Zhi‐Xin , Xie Heng‐Shen 
Published: November 2020

AbstractMetal organic framework (MOF) derived catalysts have been widely used in biomass platform compounds (BPC) hydrogenation field. This mini‐review selectively introduces the research progress of MOFs derived catalysts in the upgrading of BPC. Particularly, MOFs derived catalysts prepared by pyrolysis and their catalytic applications for furfural and 5‐hydroxymethylfurfural are summarized in this mini‐review. In addition, the factors affecting the performance of MOFs derived catalysts prepared by pyrolysis are discussed briefly and then the potential improvement studies on MOFs derived catalysts prepared by pyrolysis for upgrading of BPC are also put forward. We deem that this mini‐review will provide valuable insights into the design and application of MOFs derived catalysts prepared by pyrolysis for upgrading of BPC to bio‐based chemicals.