bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iridoid Sex Pheromone Biosynthesis in Aphids Mimics Iridoid‐Producing Plants
Authors: Partridge Suzanne J. , Withall David M. , Caulfield John C. , Pickett John A. , Stockman Robert A. , Oldham Neil J. , Birkett Michael A. 
Published: April 2021

AbstractBiosynthesis of (1R,4aS,7S,7aR)‐nepetalactol (1) and (4aS,7S,7aR)‐nepetalactone (2) in plants involves iridoid synthase (ISY), an atypical reductive cyclase that catalyses the reduction of 8‐oxogeranial into the reactive enol of (S)‐8‐oxocitronellal, and cyclization of this enol intermediate, either non‐enzymatically or by a nepetalactol‐related short chain dehydrogenase enzyme (NEPS) that yields the nepetalactols. In this study, we investigated the biosynthesis in vivo of 1 and 2 in the pea aphid, Acyrthosiphon pisum, using a library of isotopically‐labelled monoterpenoids as molecular probes. Topical application of deuterium‐labelled probes synthesized from geraniol and nerol resulted in production of 2H4−lactol 1 and 2H4−lactone 2. However, deuterium incorporation was not evident using labelled probes synthesized from (S)‐citronellol. These results suggest that iridoid biosynthesis in animals, specifically aphids, may follow a broadly similar route to that characterised for plants.
Highly Selective Ortho‐Directed Dicarboxylation of Cyclopentadiene by Methylcarbonates and CO2 or COS – First Insight into Co‐ordination Chemistry of New Ambident Ligands
Authors: Vollgraff Tobias , Sundermeyer Jörg 
Published: April 2021

AbstractThis research presents the highly regioselective syntheses of 1,2‐dicarboxylated cyclopentadienide salts [Cat]2[C5H3(CO2)2H] by reaction of a variety of organic cation methylcarbonate salts [Cat]OCO2Me (Cat=NR4+, PR4+, Im+) with cyclopentadiene (CpH) or by simply reacting organic cation cyclopentadienides Cat[Cp] (Cat=NR4+, PR4+, Im+) with CO2. One characteristic feature of these dianionic ligands is the acidic proton delocalized in an intramolecular hydrogen bridge (IHB) between the two carboxyl groups, as studied by 1H NMR spectroscopy and XRD analyses. The reaction cannot be stopped after the first carboxylation. Therefore, we propose a Kolbe‐Schmitt phenol‐carboxylation related mechanism where the acidic proton of the monocarboxylic acid intermediate plays an ortho‐directing and CO2 activating role for the second kinetically accelerated CO2 addition step exclusively in ortho position. The same and related thiocarboxylates [Cat]2[C5H3(COS)2H] are obtained by reaction of COS with Cat[Cp] (Cat=NR4+, PR4+, Im+). A preliminary study on [Cat]2[C5H3(CO2)2H] reveals, that its soft and hard coordination sites can selectively be addressed by soft Lewis acids (Mo0, Ru2+) and hard Lewis acids (Al3+, La3+).
Natural‐Like Spirocyclic Δα,β‐Butenolides Obtained from Diazo Homophthalimides
Authors: Dar'in Dmitry , Kantin Grigory , Chupakhin Evgeny , Sharoyko Vladimir , Krasavin Mikhail 
Published: April 2021

Abstractα‐Diazo homophotalimides were reacted with various propiolic acids on Rh2(esp)2 catalysis. The resulting propiolate esters were transformed into novel, heterocyclic Δα,β‐spirobutenolides in good to excellent product yields. The approach represents a fundamentally novel entry into natural‐like Δα,β‐spirobutenolides present in many biologically active natural products as well as fully synthetic compounds endowed with diverse biological activities. The Δα,β‐spirobutenolides thus obtained were shown to inhibit thioredoxin reductase, a selenocysteine enzyme target for cancer. Moreover, for the best compound in the series (TrxR IC50 1.49±0.08 μM), by using MALDI‐TOF mass‐spectrometry it was shown that it selectively binds selenocysteine in the presence of a 10‐fold excess of cysteine. This validates the new compound as a promising lead for anticancer therapy development.
Preparation of Artificial Hexaplex Composed of Non‐Natural Nucleic Acid
Authors: Makino Koki , Hattori Yuhei , Kashida Hiromu , Asanuma Hiroyuki 
Published: April 2021

AbstractThis article describes synthetic procedures for acyclic D‐threoninol nucleic acid tethering of bifacial nucleobases. Because these nucleobases have complementary hydrogen bonding sites on both sides, their oligomers can form a hexaplex. These hexaplexes are suitable for use as metal or pH sensors and as supramolecular motifs. © 2021 Wiley Periodicals LLC.Basic Protocol 1: Synthesis of D‐threoninol backboneBasic Protocol 2: Synthesis of D‐aTNA tethering cyanuric acidBasic Protocol 3: Synthesis of D‐aTNA tethering a 2‐aminopyrimidine moietyBasic Protocol 4: Synthesis of D‐aTNA tethering a 2,4,6‐triaminopyrimidine moietyBasic Protocol 5: Synthesis of D‐aTNA oligomer tethering cyanuric acid, 2‐aminopyrimidine, or 2,4,6‐triaminopyrimidine
Distributed denial‐of‐service attack mitigation in network functions virtualization‐based 5G networks using management and orchestration
Authors: Köksal Sarp , Dalveren Yaser , Maiga Bamoye , Kara Ali 
Published: April 2021

SummaryThe fifth generation (5G) technology is expected to allow connectivity to billions of devices, known as Internet of Things (IoT). However, IoT devices will inevitably be the main target of various cyberattack types. The most common one is known as distributed denial‐of‐service (DDoS) attack. In order to mitigate such attacks, network functions virtualization (NFV) has a great potential to provide the benefit of elasticity and low‐cost solutions for protecting 5G networks. In this context, this study proposes a new mechanism developed to mitigate DDoS attacks in 5G NFV networks. The proposed mechanism utilizes intrusion prevention system's (IPS) virtual machines (VMs) to intercept the queries. Based on the volume of DDoS traffic, IPS's VMs are dynamically deployed by means of management and orchestration (MANO) in order to balance the load. To evaluate the effectiveness of the mechanism, experiments are conducted in a real 5G NFV environment built by using 5G NFV environment tools. To our best knowledge, this is the first time that NFV‐based mechanism is experimentally tested in a real 5G NFV environment for mitigating DDoS attacks in 5G networks. The experimental results verify that the proposed mechanism can mitigate DDoS attacks effectively.
An ecohydrological typology for thermal refuges in streams and rivers
Authors: Sullivan Christopher J. , Vokoun Jason C. , Helton Ashley M. , Briggs Martin A. , Kurylyk Barret L. 
Published: April 2021

AbstractThermal refuges are thermally distinct riverscape features used by aquatic organisms during unfavourable thermal events, facilitating resilience in marginal environments. However, the thermal refuge concept is nebulous, and the often interchangeable use of the term ‘thermal refugia’ creates additional ambiguity. We argue that lexical differences resulting from divergent scholarly trainings hinder holistic understanding of thermal refuges; thus, existing studies would benefit from a structured framework for thermal refuge conceptualization. Herein, we articulate an ecohydrological typology for defining and characterizing thermal refuges in streams and rivers by identifying key hydrological and thermal characteristics and variations in ecological function described in the literature. We use concepts that are easily definable, measurable and transferable across disciplines, riverscapes and species to discriminate among thermal refuge types. Future work can use our typology as a basis for more informed interdisciplinary discussion and interpretation of thermal refuges' role in riverscapes through more hypothesis‐driven research and conservation‐focused management.
Synthesis and Characterization of Geminal Diazido Derivatives Based on Diethyl Malonate
Authors: Harter Alexander G. , Klapötke Thomas M. , Riedelsheimer Christian , Stierstorfer Jörg , Voggenreiter Michael 
Published: April 2021

AbstractNew geminal diazide derivatives based on diethyl 2,2‐diazidomalonate (1) are presented. 2,2‐Diazidomalonic acid (2) as well as four alkaline and nitrogen rich salts of 2,2‐diazidomalonate (3–6) were synthesized and extensively characterized e. g. by low temperature X‐ray diffraction. All compounds, which represent promising starting materials for further nitrogen‐rich materials, were analyzed by 1H and 13C NMR spectroscopy, elemental analysis, differential thermal analysis (DTA) and regarding their sensitivity towards impact, friction, and electrostatic discharge according to BAM standard techniques. In addition, all synthesized compounds were evaluated regarding their energetic behavior using the EXPLO5 code and compared to TNT in order to provide a comparison to a well‐known energetic material. In addition, two selected compounds were investigated towards their aquatic toxicity, using the bioluminescent bacteria vibrio fischeri.
Functionalized Thieno[3,2‐b]pyrroles from Acylthiophenes, Acetylene Gas and Hydrazines in Two Steps
Authors: Schmidt Elena Yu. , Semenova Nadezhda V. , Tatarinova Inna V. , Ushakov Igor A. , Vashchenko Alexander V. , Trofimov Boris A. 
Published: April 2021

AbstractThieno[3,2‐b]pyrroles with N‐arylamino and 3‐thienoylpropyl functionalities are synthesized in up to 68 % yield from acylthiophenes, acetylene gas and hydrazines via the intermediate methylene‐6,8‐dioxabicyclo[3.2.1]octanes, which undergo multi‐position structural reorganization into the title compounds in the presence of hydrazines and TFA.
Spreadsheet analysis of the field‐driven start‐up flow in a microfluidic channel
Authors: Mondal Pranab Kumar , Roy Manideep 
Published: April 2021

AbstractWe discuss, in this article, the solution method of the unsteady electroosmotic flow of Newtonian fluid in a square microfluidic channel cross‐section in the framework of spreadsheet analysis. We demonstrate the implementation of the finite difference scheme, which is used for the discretization of the transport equations governing the flow dynamics of the present problem, in the spreadsheet tool. Also, we have shown the implementation details of different boundary conditions, which are typically used for the underlying electrohydrodynamics in a microfluidic channel, in the spreadsheet analysis tool. We show that the results obtained from the spreadsheet analysis match accurately with the numerical solutions for both the electrostatic potential distribution and the flow velocity. Our results of this analysis justify the credibility of the spreadsheet tool for capturing the intricate details of the electrically actuated microflows during the initial transiences, that is, for the start‐up flows and the phenomenon due to the electrical double layer effect, quite effectively. The inferences of this analysis will open up a new research paradigm of microfluidics and microscale transport processes by providing the potential applicability of the spreadsheet tools to obtain the flow physics of our interest in a very intuitive and less expensive manner.
Delay bound estimation for multicarrier 5G systems considering lognormal beta traffic envelope and stochastic service curve
Authors: Cardoso Álisson Assis , Ferreira Marcus Vinícius Gonzaga , Vieira Flávio Henrique Teles 
Published: April 2021

AbstractIn this article, we propose an approach for estimating delay bound on user data in the downlink of wireless multicarrier 5G networks. To this end, we propose a stochastic arrival curve based on the parameters of a lognormal beta multifractal traffic model. More specifically, we present a delay bound equation that takes into account this novel stochastic arrival curve and a stochastic service curve for multicarrier systems. Simulations are carried out to confirm that the precision of the delay bound estimation using network calculus is enhanced by considering the proposed arrival envelope and service curve.
Disparities and guideline adherence for HPV testing among patients with oropharyngeal squamous cell carcinoma, NCDB, and SEER
Authors: Husain Solomon , Lohia Shivangi , Petkov Valentina , Blackwell Timothy , Swisher‐McClure Samuel , Mizrachi Aviram , Morris Luc G. , Cohen Marc A. , Wong Richard J. , Roman Benjamin R. 
Published: April 2021

AbstractBackgroundHuman papilloma virus testing for oropharyngeal squamous‐cell carcinoma has been recommended by the National Comprehensive Cancer Network since 2012. We examine disparities, reported rates of human papillomavirus (HPV) testing, and the impact on these findings of limitations with the variable in database registries.MethodsThe HPV variable was queried for patients with oropharyngeal squamous carcinoma (OPSCC) from 2013 to 2016 in National Cancer Data Base (NCDB) and Surveillance, Epidemiology, and End Results (SEER). Multivariable regression was used to identify disparities based on sociodemographic variables. Sensitivity analyses were used to investigate limitations of the variable.ResultsDespite limitations in the HPV variable in the databases, there was less than 100% adherence to recommended testing, and there were significant disparities in multiple sociodemographic variables. For example, in NCDB 70% of white versus 60.4% of black patients were tested (odds ratio [OR] 0.75, confidence interval [CI] 0.66–0.85, p ≤ 0.0001); in SEER 59.8% of white and 47.6% of black patients were tested (OR 0.73, CI 0.67–0.81; p ≤ 0.0001).ConclusionsDisparities exist among patients undergoing testing for HPV‐associated OPSCC and adherence to guideline recommended HPV testing has been suboptimal. In addition, the HPV variable definition, especially as it relates to p16 positivity, and use in these two registries should be improved.
Mesenchymal stem cells enhance the impact of KIR receptor‐ligand mismatching on acute graft‐versus‐host disease following allogeneic hematopoietic stem cell transplantation in patients with acute myeloid leukemia but not in those with acute lymphocytic leukemia
Authors: Zhang Yu , Zheng Hao , Ren Jinhua , Luo Xiaofeng , Zheng Zhihong , Zheng Jing , Zheng Xiaoyun , Chen Yi , Chen Zhizhe , Hu Jianda , Yang Ting 
Published: April 2021

AbstractKiller cell immunoglobulin‐like receptor (KIR) receptor‐ligand mismatch has been shown to be protective for acute and chronic graft‐versus‐host disease (aGVHD, cGVHD) following allogeneic hematopoietic stem cell transplantation (allo‐HSCT) for acute leukemia. Mesenchymal stem cells (MSC) have been considered as one of the most promising prophylaxis for severe GVHD. However, there are no prospective or retrospective studies determining whether they can work synergistically on GVHD. To investigate the potential influence of KIR matching and MSCs, and their synergism on aGVHD and cGVHD after allo‐HSCT in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) patients. Data from 104 patients with AML and 50 patients with ALL treated with allo‐HSCT in the transplantation unit were retrospectively analyzed. KIR genotyping was performed by the PCR‐SSO method. The amplicons were quantified on the Luminex 200 flow analyzer and analyzed using the Quick‐Type for Lifecodes software to generate KIR data. Cox proportional hazards models were used in multivariate analyses. KIR receptor‐ligand matching was associated with an increased risk of grade II–IV aGVHD compared to KIR receptor‐ligand mismatching (p < 0.001) in AML patients, but KIR ligand‐mismatching had no significant effect on aGVHD or cGVHD in ALL patients. In contrast, MSCs reduced the incidence of grade II–IV aGVHD in both AML and ALL patients (AML: p = 0.006; ALL: p = 0.008) regardless of KIR mismatching. The combination of KIR receptor‐ligand mismatch and MSC transplantation significantly suppressed grade II–IV aGVHD occurrence in AML patients (p = 0.039). In the KIR mismatch group, the incidence of aGVHD was 2.8% in patients receiving MSC compared to 14.6% in those who did not (p = 0.047). KIR receptor‐ligand mismatch, MSC transplantation and their combined use significantly reduced the risk of aGVHD after allo‐HSCT. These data provide a clinically applicable strategy to reduce aGVHD, thus improving allo‐HSCT outcome.
MRI Study of Jellyfish Collagen, Hyaluronic Acid, and Cadaveric Dermis for Injection Laryngoplasty
Authors: San‐Marina Serban , Bowen Andrew J. , Oldenburg Michael S. , Voss Stephen G. , Hunter Danielle E. , Macura Slobodan , Meloche Ryan , Miller Alen Lee , Spragg Andrew Mearns , Ekbom Dale C. 
Published: April 2021

AbstractObjectives/HypothesisTest a new jellyfish collagen biomaterial aimed to increase duration of injection medialization laryngoplasty (IL) against two products in clinical practice.Study DesignAnimal model.MethodsLeft recurrent laryngeal nerve sectioning and IL were performed in New Zealand White rabbits (N = 6/group). Group 1 received micronized cross‐linked jellyfish collagen (MX‐JC) and adipose derived stem cells (ADSCs), Group 2, MX‐JC alone, Group 3, cross‐linked hyaluronic acid (X‐HA), and Group 4, micronized acellular dermis (MACD). Animals were sacrificed at 4 and 12 weeks. Major outcomes were MRI tissue volumes and histopathology.ResultsAfter 100 μL IL MRI volumes (means ± STD) at 4 and 12 weeks were: Group 1: 27.2 ± 15.6 and 13.1 ± 5.2 μL, Group 2: 60.8 ± 18 and 27.8 ± 2.47 μL, Group 3: 27.4 ± 12 and 10.6 ± 8 μL, and Group 4: 37.5 ± 11 and 9.85 ± 1 μL. Group 2 volumes were largest and Group 3 were smallest in all comparisons (P < .05). Histologically, low grade inflammatory responses were observed in Group 1, mild histiocytic infiltration in Group 2, widespread muscle fiber loss in Group 3, and plasmocytic infiltration in Group 4.ConclusionsMX‐JC showed the least resorption at 4 and 12 weeks among all groups. T cell inflammatory responses were observed with MX‐JC but were reduced by 12 weeks while B cell immune responses, indicative of antibody priming, were predominantly noted with MACD. MX‐JC + ADSC showed low grade immunity while the XHA showed greater myocyte loss compared to the other groups.Level of EvidenceNA Laryngoscope, 131:E2452–E2460, 2021
New Stratagem for Designing High‐Performance Thermoplastic Polyurethane by Using a New Chain Extender
Authors: Hu Shikai , Shou Tao , Fu Guoqing , Zhao Xiuying , Wang Zhao , Zhang Liqun 
Published: April 2021

AbstractThe high content and regular distribution of hard segment (HS) are necessary to achieve high‐performance thermoplastic polyurethane (TPU), and the HS unit of TPU is generated from the reaction of diisocyanate and chain extender. However, the traditional chain extenders are mainly aliphatic diol that cannot provide rigid groups to improve polyurethane performances. Herein, a novel chain extender bis(hydroxyethyloxycarbonylamino)hexane (BHH) that contains two urethane groups is designed and used to construct high‐performance TPU by increasing content and regular distribution of HS. BHH is synthesized using ethylene carbonate (EC) and hexamethylenediamine (HDA) via a ring‐opening reaction. Subsequently, the effect of BHH on the polyurethane performances is studied with respect to a typical TPU by using polytetramethylene ether glycol (PTMG) and hexamethylene diisocyanate (HDI) as the starting materials. The amount of HDI considerably differs for each polyurethane, aiming to ensure the same total content of urethane groups. When compared with the traditional ethylene glycol‐extended polyurethane, the size and distribution of the HS domains of the BHH‐extended polyurethane are obviously more homogeneous, which proves BHH‐extended polyurethane has better microphase separation. Furthermore, ordered hydrogen bonding, the mechanical properties, and heat‐resistance performance are significantly improved, suggesting a potential method to design TPU delivering outstanding performance.
Encapsulation by Directed PISA: RAFT‐Based Polymer‐Vesiculated Pigment for Opacity Enhancement in Paint Films
Authors: Nguyen Duc , Huynh Vien , Lam Minh , Serelis Algirdas , Davey Tim , Paravagna Olga , Such Chris , Hawkett Brian 
Published: April 2021

AbstractA novel method is demonstrated to encapsulate titanium dioxide pigment using directed polymerization‐induced self‐assembly (PISA) with reversible addition‐fragmentation chain‐transfer (RAFT) controlled emulsion polymerization. The polymerization is carried out in a batch process in which both styrene (Sty) and the pigment are emulsified using triblock amphiphilic macro‐RAFT copolymers as stabilizers. RAFT‐controlled chain growth leads to directed lamellar self‐assembly, forming polystyrene (PS) shells’ encapsulating pigment particles with 100% efficiency. The pigment resides either at centers of single‐void vesicles or within the interior of multivoid vesiculated particles. The presence of complex morphologies such as spherical particles, nanofibers, nanoplatelets, and polymer vesicles confirms the PISA pathway. The process is optimized to preferably produce polymer‐vesiculated pigment for use as an enhanced opacifier in water‐based paint.
In Situ Preparation of Mechanically Enhanced Hydrogel via Dispersion Polymerization in Aqueous Solution
Authors: Chen Honggui , Zhang Xiang , Lin Ziyu , Zhang Rui , Yu Bingran , Li Yang , Xu Fu‐Jian 
Published: April 2021

AbstractHydrogels with improved mechanical properties can expand to a greater range of applications. The fabrication of conventional toughened hydrogels typically requires precise modifications, multiple components, and complex steps. Here, a straightforward “one‐step” polymerization method for the in situ preparation of hydrogels in aqueous solutions, is reported. Inspired by polymerization‐induced self‐assembly (PISA), water‐miscible monomers are copolymerized during the hydrogel fabrication; the growing blocks eventually form physical bridges thus providing a mechanism for effective energy dissipation. The rheological and mechanical properties are evaluated and the results reveal that this strategy can be an effective approach to design mechanically enhanced hydrogels for a wide range of applications.
Surgery with emicizumab prophylaxis for two paediatric patients with severe haemophilia A with inhibitors
Authors: Lockhart Marguerite , Tardy‐Poncet Brigitte , Montmartin Aurélie , Noyel Pauline , Thouvenin Sandrine , Berger Claire 
Published: April 2021

AbstractEmicizumab is a prophylaxis for patients with severe haemophilia A with and without inhibitor. Despite weekly administration of emicizumab, coagulation states stay below normal value and cannot be assessed by standard haemostasis tests. In our two patients, we used the thrombin‐generation assay (endogenous thrombin potential and Peak) to monitor the patient's clotting status. Under emicizumab, it is necessary to add a bypassing agent (BPA) such as rFVIIa (Novoseven) to avoid bleeding before surgery. The BPA dosage was based on a thrombin‐generation assay and collegial consultation.
Flexural behavior of PVA‐FRC GFRP reinforced concrete beams
Authors: Sun Qiang , Jin Qingping , Gao Yonghong , Li Hong , Cao Yugui 
Published: April 2021

AbstractFiber reinforced concrete beams are a popular research topic because of the improvement in the performance of concrete beams with fibers. PVA‐FRC GFRP reinforced concrete beams have better mechanical properties than those of ordinary reinforced concrete beams when considering the combination of multidirectional material properties. This article presents the results of an experimental study on the flexural behavior of PVA‐FRC GFRP reinforced concrete beams. Seven GFRP concrete beams were tested. The test variables included the PVA fiber content and GFRP diameter. The test results indicated that the existence of GFRP bars is effective for enhancing the load‐carrying capacity of RC beams and that PVA fibers can substantially inhibit the development of cracks in PVA‐FRC GFRP reinforced concrete beams and increase the midspan deflection. The experimental midspan deflection and maximum crack widths are also compared with theoretical predictions using new guidelines from the American Concrete Institute. Finally, the maximum crack correction formula for PVA‐FRC GFRP reinforced concrete beams is proposed.