bluuebunny/crossref_metadata_2025 huggingface dataset:
Origins of Endo Selectivity in Diels–Alder Reactions of Cyclic Allene Dienophiles
Authors: Ramirez Melissa , Svatunek Dennis , Liu Fang , Garg Neil K. , Houk Kendall N.
Published: April 2021

Strained cyclic allenes, first discovered in 1966 by Wittig and co‐workers, have recently emerged as valuable synthetic building blocks. Previous experimental investigations, and computations reported here, demonstrate that the Diels–Alder reactions of furans and pyrroles with 1,2‐cyclohexadiene and oxa‐ and azaheterocyclic analogs proceed with endo selectivity. This endo selectivity gives the adduct with the allylic saturated carbon of the cyclic allene endo to the diene carbons. The selectivity is very general and useful in synthetic applications. Our computational study establishes the origins of this endo selectivity. We analyze the helical frontier molecular orbitals of strained cyclic allenes and show how secondary orbital and electrostatic effects influence stereoselectivity. The LUMO of carbon‐3 of the allene (C‐3 is not involved in primary orbital interactions) interacts in a stabilizing fashion with the HOMO of the diene in such a way that the carbon of the cyclic allene attached to C‐1 favors the endo position in the transition state. The furan LUMO, allene HOMO interaction reinforces this preference. These mechanistic studies are expected to prompt the further use of long‐avoided strained cyclic allenes in chemical synthesis.
The Origin of Catalytic Benzylic C−H Oxidation over a Redox‐Active Metal–Organic Framework
Authors: Kimberley Louis , Sheveleva Alena M. , Li Jiangnan , Carter Joseph H. , Kang Xinchen , Smith Gemma L. , Han Xue , Day Sarah J. , Tang Chiu C. , Tuna Floriana , McInnes Eric J. L. , Yang Sihai , Schröder Martin
Published: April 2021

Selective oxidation of benzylic C−H compounds to ketones is important for the production of a wide range of fine chemicals, and is often achieved using toxic or precious metal catalysts. Herein, we report the efficient oxidation of benzylic C−H groups in a broad range of substrates under mild conditions over a robust metal–organic framework material, MFM‐170, incorporating redox‐active [Cu2II(O2CR)4] paddlewheel nodes. A comprehensive investigation employing electron paramagnetic resonance (EPR) spectroscopy and synchrotron X‐ray diffraction has identified the critical role of the paddlewheel moiety in activating the oxidant tBuOOH (tert‐butyl hydroperoxide) via partial reduction to [CuIICuI(O2CR)4] species.
A Pair of Cobalt(III/IV) Terminal Imido Complexes
Authors: Mao Weiqing , Fehn Dominik , Heinemann Frank W. , Scheurer Andreas , Munz Dominik , Meyer Karsten
Published: April 2021

The reaction of the cobalt(I) complex [(TIMMNmes)CoI](BPh4) (2) (TIMMNmes=tris‐[2‐(3‐mesitylimidazolin‐2‐ylidene)methyl]amine) with 1‐adamantylazide yields the cobalt(III) imido complex [(TIMMNmes)CoIII(NAd)](BPh4) (3) with concomitant release of dinitrogen. The N‐anchor in diamagnetic 3 features an unusual, planar tertiary amine, which results from repulsive electrostatic interaction with the filled d(z2)‐orbital of the cobalt ion and negative hyperconjugation with the neighboring methylene groups. One‐electron oxidation of 3 with [FeCp2](OTf) provides access to the rare, high‐valent cobalt(IV) imido complex [(TIMMNmes)CoIV(NAd)](OTf)2 (4). Despite a half‐life of less than 1 h at room temperature, 4 could be isolated at low temperatures in analytically pure form. Single‐crystal X‐ray diffractometry and EPR spectroscopy corroborate the molecular structure and the d5 low‐spin, S=
, electron configuration. A computational analysis of 4 suggests high covalency within the CoIV=NAd bond with non‐negligible spin density located at the imido moiety, which translates into substantial triplet nitrene character.
Hydrogen peroxide‐producing electrochemical bandage controlled by a wearable potentiostat for treatment of wound infections
Authors: Mohamed Abdelrhman , Anoy MD Monzurul Islam , Tibbits Gretchen , Raval Yash S. , Flurin Laure , Greenwood‐Quaintance Kerryl E. , Patel Robin , Beyenal Haluk
Published: April 2021

Chronic wound infections caused by biofilm‐forming microorganisms represent a major burden to healthcare systems. Treatment of chronic wound infections using conventional antibiotics is often ineffective due to the presence of bacteria with acquired antibiotic resistance and biofilm‐associated antibiotic tolerance. We previously developed an electrochemical scaffold that generates hydrogen peroxide (H2O2) at low concentrations in the vicinity of biofilms. The goal of this study was to transition our electrochemical scaffold into an H2O2‐generating electrochemical bandage (e‐bandage) that can be used in vivo. The developed e‐bandage uses a xanthan gum‐based hydrogel to maintain electrolytic conductivity between e‐bandage electrodes and biofilms. The e‐bandage is controlled using a lightweight, battery‐powered wearable potentiostat suitable for use in animal experiments. We show that e‐bandage treatment reduced colony‐forming units of Acinetobacter buamannii biofilms (treatment vs. control) in 12 h (7.32 ± 1.70 vs. 9.73 ± 0.09 log10[CFU/cm2]) and 24 h (4.10 ± 12.64 vs. 9.78 ± 0.08 log10[CFU/cm2]) treatments, with 48 h treatment reducing viable cells below the limit of detection of quantitative and broth cultures. The developed H2O2‐generating e‐bandage was effective against in vitro A. baumannii biofilms and should be further evaluated and developed as a potential alternative to topical antibiotic treatment of wound infections.
Expanding the Substrate Scope of Nitrating Cytochrome P450 TxtE by Active Site Engineering of a Reductase Fusion
Authors: Saroay Rakesh , Roiban Gheorghe‐Doru , Alkhalaf Lona M. , Challis Gregory L.
Published: April 2021

Aromatic nitration reactions are a cornerstone of organic chemistry, but are challenging to scale due to corrosive reagents and elevated temperatures. The cytochrome P450 TxtE nitrates the indole 4‐position of l‐tryptophan at room temperature using NO, O2 and NADPH, and has potential to be developed into a useful aromatic nitration biocatalyst. However, its narrow substrate scope (requiring both the α‐amino acid and indole functionalities) have hindered this. Screening of an R59 mutant library of a TxtE‐reductase fusion protein identified a variant (R59C) that nitrates tryptamine, which is not accepted by native TxtE. This variant exhibits a broader substrate scope than the wild type enzyme and is able to nitrate a range of tryptamine analogues, with significant alterations to the aromatic and aminoethyl moieties.
Long‐term outcomes of self‐expanding versus balloon‐expandable transcatheter aortic valves: Insights from the OBSERVANT study
Authors: Costa Giuliano , D'Errigo Paola , Rosato Stefano , Valvo Roberto , Biancari Fausto , Tamburino Corrado , Cerza Francesco , Cicala Stefano Domenico , Seccareccia Fulvia , Barbanti Marco ,   for the OBSERVANT Research Group
Published: April 2021

Objectives

To compare clinical outcomes of balloon‐expandable (BE) and self‐expanding (SE) transcatheter aortic valves (TAVs) up to 5 years.

Background

To date, no robust, comparative data of BE and SE TAVs at long‐term are available.

Methods

We considered a total of 1,440 patients enrolled in the multicenter OBSERVANT study and undergoing transfemoral transcatheter aortic valve implantation (TF‐TAVI) with either supra‐annular SE (n = 830, 57.6%) and intra‐annular BE (n = 610, 42.4%) valves. Clinical outcomes of the two groups were compared after adjustment using inverse probability of treatment weighting (IPTW) and confirmed by sensitivity analysis with propensity score matching.

Results

Patients receiving SE valve showed a higher all‐cause mortality at 5 years (Kaplan–Meier estimates 52.3% vs. 47.7%; Hazard ratio [HR] 1.18, 95% confidence interval [CI] 1.01–1.38, p = .04). Landmark analyses showed that there was a not statistically significant reversal of risk excess against the BE group starting from 3 years after TAVI (3–5 years HR 0.97, 95% CI 0.76–1.25, p = .86). Post‐procedural, moderate/severe paravalvular regurgitation (PVR)(HR 1.46, 95% CI 1.14–1.87; p < .01) and acute kidney injury (AKI)(HR 3.89, 95% CI 2.47–6.38; p < .01) showed to be independent predictors of 5‐year all‐cause mortality in multivariable analysis.

Conclusions

Considering the intrinsic limitations of the OBSERVANT study, we found that patients undergoing TF‐TAVI with a supra‐annular SE valve had a higher all‐cause mortality compared to those receiving an intra‐annular BE valve at 5 years. A late catch up phenomenon of patients receiving the BE valve was observed beyond 3 years. Post‐procedural moderate/severe PVR seems to play a crucial role in determining this finding. Comparative studies of new generation devices with longer follow‐up are needed to evaluate the benefit of each specific TAV type.
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

Biosynthesis 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

This 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

α‐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

This 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 backbone

Basic Protocol 2: Synthesis of D‐aTNA tethering cyanuric acid

Basic Protocol 3: Synthesis of D‐aTNA tethering a 2‐aminopyrimidine moiety

Basic Protocol 4: Synthesis of D‐aTNA tethering a 2,4,6‐triaminopyrimidine moiety

Basic 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

The 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

Thermal 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

New 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

Thieno[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

We 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.
Internship program offers win‐win for your unit, students
Authors: Pavlik Amelia
Published: April 2021

Good help is hard to come by — and pay for. This was a challenge Heidi Hoskinson was very familiar with in her role as Vice President of Enrollment Management and Registrar at Rogers State University.
Pre‐COVID‐19 realities will become post‐COVID‐19 inevitables
Authors: Dennis Marguerite J.
Published: April 2021

It will take some time before we can completely unpack the long‐term impact of COVID‐19 on higher education, but what is clear is that the pandemic accelerated several trends that were already taking place in higher education.
Recent research shows dismal outcome for community college enrollment during COVID‐19
Authors: Sutton Halley
Published: April 2021

It's no secret that the pandemic has had far‐ranging and potentially devastating effects on higher education. Recent research has indicated that community colleges have been hit especially hard by the pandemic, causing drops in enrollment as well as drops in college persistence.
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

In 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.
ERCOT—The Eyes of Texas (and the World) Are Upon You: What Can be Done to Avoid a February 2021 Repeat
Authors: Smead Richard G.
Published: April 2021

The President's Day 2021 Texas power market catastrophe managed by the Electric Reliability Council of Texas (ERCOT) is already legendary. The massive power outage in the face of Winter Storm Uri has been written about and critiqued both nationally and internationally. Those critiquing the event have treated the crisis as either a failure of the unregulated generator market model, a failure of a poorly designed unregulated market, a symbol of overdone Texan independence (in its isolation from other power markets), and, not surprisingly, a failure of renewable wind and solar power, according to the political opponents of those sources. Pundits have had a field day chasing their pet theories, and politicians have held numerous hearings and made strong declarations as to how this will never happen again, and even possibly undo the pricing of power during the crisis. Politicians have also been pointing fingers of blame, often misplaced. As one of the millions who spent that night huddled around a fireplace with my family trying to stay warm, I certainly hope the politicians are right that this will never happen again—but I am pretty sure they do not even understand the basic problem that Texas faced.
The Role of Hydrogen in our Energy Future
Authors: de Ramos Kevin Monte
Published: April 2021

In my first column for Energy and Climate (Our Energy Future, August 2020), this author suggested a need for investments in renewable baseload generation. When renewables are discussed, the context focuses on the intermittency and distributed nature of renewable generation. This is no less evident than in the definition of renewables provided by the US Energy Information Agency (EIA).
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

Background

Human 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.

Methods

The 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.

Results

Despite 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).

Conclusions

Disparities 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

Killer 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.
Online preschool education optimization based on edge computing in the era of COVID‐19
Authors: Duan Xiaoxuan
Published: April 2021

Under the influence of COVID‐19, people's normal life and activities have been limited, such as the education of children, which leads to the emergence of online preschool education. Since online preschool education is large‐scale and time‐sensitive, the traditional network model cannot satisfy the needs of online education. In this paper, edge computing is adopted to optimize online preschool education, where a task unloading algorithm based on genetic algorithm (TUOGA) is designed to minimize the computing delay of terminal tasks. In order to verify the effectiveness and efficiency of the proposed algorithm, TUOGA is compared with two task offloading algorithms, and simulation results show that the proposed algorithm outperforms them in the aspect of time latency.
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

Objectives/Hypothesis

Test a new jellyfish collagen biomaterial aimed to increase duration of injection medialization laryngoplasty (IL) against two products in clinical practice.

Study Design

Animal model.

Methods

Left 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.

Results

After 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.

Conclusions

MX‐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 Evidence

NA 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

The 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

A 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

Hydrogels 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.
Note on a difference equation and some of its relatives
Authors: Stević Stevo , Ahmed Ahmed El‐Sayed , Kosmala Witold , Šmarda Zdeněk
Published: April 2021

We prove an interesting result on convergence of positive solutions to a nonlinear second‐order difference equation of interest to some two‐periodic solutions to the equation, improving a previous result, and leave an open problem. We also present a method for a unified treatment of closely related nonlinear difference equations, which appear from time to time in the literature.
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

Emicizumab 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

Fiber 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.
Scutellarin ameliorates the stress‐induced anxiety‐like behaviors in mice by regulating neurotransmitters
Authors: Guo Yan‐yan , Zhou Ying , Li Yu‐jiao , Liu An , Yue Jiao , Liu Qing‐qing , Yang Le , Wu Yu‐mei , Liu Shui‐bing , Zhang Kun , Zhao Ming‐gao
Published: April 2021

Anxiety disorders are a common frequently psychiatric symptom in patients that lead to disruption of daily life. Scutellarin (Scu) is the main component of Erigeron breviscapus, which has been used as a neuroprotective agent against glutamate‐induced excitotoxicity. However, the potential effect of Scu on the stress‐related neuropsychological disorders has not been clarified. In this study, Anxiety‐like behavior was induced by acute restraint stress in mice. Scu were injected intraperitoneally (twice daily, 3 days). Results showed that Scu exhibited good protective activity on mice by decreasing transmitter release levels. Restraint stress caused significant anxiety like behavior in mice. Treatment of Scu could significantly improve the moving time of open arms in Elevated Plus Maze and central time on open field test. Scu treatment suppressed action potential firing frequency, restored excessive presynaptic quantal release, and down‐regulated glutamatergic receptor expression levels in the prefrontal cortex (PFC) of stressed mice. GABAARα1 and GABAAγ2 expression in the brain PFC tissues of mice were nearly abrogated by Scu treatment. In stress‐induced anxiety mice, stress can increase the frequency of mini excitatory postsynaptic currents (mEPSC), which can be reversed by Scu treatment. Therefore, Scu has a potent anxiolytic activity and may be valuable for the treatment of stress‐induced anxiety disorders.
The effects of nano‐curcumin supplementation on glycemic control, blood pressure, lipid profile, and insulin resistance in patients with the metabolic syndrome: A randomized, double‐blind clinical trial
Authors: Bateni Zohre , Rahimi Hamid Reza , Hedayati Mehdi , Afsharian Shila , Goudarzi Razieh , Sohrab Golbon
Published: April 2021

Metabolic syndrome (MetS) is one of the most important health hazards. Curcumin is extracted from Curcuma longa (turmeric), which can affect the components of MetS. To increase the oral bioavailability of curcumin, nano‐micelle curcumin is used instead of curcumin powder. In this randomized, double‐blind, controlled clinical trial, 50 patients with MetS were randomly assigned to two groups to receive either 80 mg/day nano‐curcumin (n = 25) or placebo (n = 25), for 12 weeks anthropometric measurements, blood pressure, and biochemical factors—including fasting blood sugar (FBS), Hemoglobin A1c (HbA1c), homeostatic model assessment (HOMA) for insulin resistance (HOMA‐IR), pancreatic β cell function (HOMA‐β) and lipid profile—were assessed at the baseline and the end of the study. Statistical analyses were done using SPSS software (Version 23). The analysis between the two groups has illustrated a significant reduction in the average change of triglyceride (TG) levels (−60.5 ± 121.7 vs. 13.1 ± 78.1 mg/dL; p < .05) and HOMA‐β (−5.7 ± 48.2 vs. −4.01 ± 16.9; p < .05). But there were no significant differences in anthropometric measurements, blood pressure and biochemical factors—including FBS, HbA1c, HOMA‐IR, HOMA‐β, and lipid profile variables include (total cholesterol, LDL‐C, and HDL‐C) at the end of the study. In conclusion, supplementation with nano‐micelle curcumin significantly improved serum TG in MetS patients.
Bayesian semiparametricmeta‐analytic‐predictiveprior for historical control borrowing in clinical trials
Authors: Hupf Bradley , Bunn Veronica , Lin Jianchang , Dong Cheng
Published: April 2021

When designing a clinical trial, borrowing historical control information can provide a more efficient approach by reducing the necessary control arm sample size while still yielding increased power. Several Bayesian methods for incorporating historical information via a prior distribution have been proposed, for example, (modified) power prior, (robust) meta‐analytic predictive prior. When utilizing historical control borrowing, the prior parameter(s) must be specified to determine the magnitude of borrowing before the current data are observed. Thus, a flexible prior is needed in case of heterogeneity between historic trials or prior data conflict with the current trial. To incorporate the ability to selectively borrow historic information, we propose a Bayesian semiparametric meta‐analytic‐predictive prior. Using a Dirichlet process mixture prior allows for relaxation of parametric assumptions, and lets the model adaptively learn the relationship between the historic and current control data. Additionally, we generalize a method for estimating the prior effective sample size (ESS) for the proposed prior. This gives an intuitive quantification of the amount of information borrowed from historical trials, and aids in tuning the prior to the specific task at hand. We illustrate the effectiveness of the proposed methodology by comparing performance between existing methods in an extensive simulation study and a phase II proof‐of‐concept trial in ankylosing spondylitis. In summary, our proposed robustification of the meta‐analytic‐predictive prior alleviates the need for prespecifying the amount of borrowing, providing a more flexible and robust method to integrate historical data from multiple study sources in the design and analysis of clinical trials.
Ultraprecision Imaging and Manipulation of Plasmonic Nanostructures by Integrated Nanoscopic Correction
Authors: Liu Yunbo , Zhang Zhijia , Park Younggeun , Lee Somin Eunice
Published: April 2021

Optical manipulation and imaging of nano‐objects with nanometer precision is highly desirable for nanomaterial and biological studies due to inherent noninvasiveness. However, time constraints and current segregated experimental systems for nanoimaging and nanomanipulation limits real‐time super‐resolution imaging with spatially enhanced manipulation. Here, an integrated nanoscopic correction (iNC) method to enable multimodal nanomanipulation‐nanoimaging is reported. The iNC consists of a multimodal voltage‐tunable power modulator, polarization rotator, and polarizer. Using the iNC, plasmonic nano‐objects which are below the diffraction limit and which can be distinguished by direct observation without post processing are demonstrated. Furthermore, such direct observations with enhanced nanometer spatial stability and millisecond high speed are shown. Precise trapping and rapid rotation of gold nanorods with the iNC are demonstrated successfully. With non‐invasive post‐processing free nanoimaging and nanomanipulation, it is anticipated that the iNC will make contributions in the nanomaterial and biological sciences requiring precision optics.
Phylogenetics of Piresia (Poaceae: Bambusoideae) reveals unexpected generic relationships within Olyreae with taxonomic and biogeographic implications
Authors: de Carvalho Maria Luiza S. , de Jesus Izabela S.D. , Bezerra Hédina B. , Oliveira Iasmin Laiane C. , van den Berg Cássio , Schnadelbach Alessandra S. , Clark Lynn G. , Oliveira Reyjane P.
Published: April 2021

Piresia, a Neotropical herbaceous bamboo genus (Poaceae, Olyreae) including six described species, has a disjunct geographic distribution involving the Caribbean and north/western South America and the northeastern Atlantic Forest in Brazil. Its phylogenetic relationships are poorly known, especially with respect to certain monotypic genera within Olyrinae, such as Reitzia, endemic to the Atlantic forest of southern/south Brazil, and Piresiella, endemic to Cuba. In order to examine the evolutionary history of Piresia, we analyzed 36 samples, including known and possible new species of the genus, as well as members of Reitzia, Piresiella and other genera of subtribes Olyrinae, Parianinae and Buergersiochloinae as the ingroup, and selected woody bamboos and Lolium (Pooideae) as the outgroups. Five regions of plastid and nuclear non‐coding DNA spacers (trnD‐trnT, trnS‐trnG, rpl32‐trnL, trnH‐psbA, ITS) were sequenced, and to estimate phylogenetic relationships, we used Bayesian inference, maximum likelihood and maximum parsimony considering the plastid regions (with and without gaps) and ITS separately. Surprisingly, Piresiella emerged as sister to the monotypic Buergersiochloa (Buergersiochloinae), endemic to New Guinea. Based on these results and morphological analysis, we discuss the implications for the biogeography of the herbaceous bamboos, formally transfer Ekmanochloa, Mniochloa and Piresiella to Buergersiochloinae, and provide an emended description of the subtribe. Three main lineages were recovered within Olyrinae, one of them comprising Piresia and Reitzia, with high support. Within this clade, the two main lineages are geographically distinct, and their evolutionary history seems to be complex and possibly related to adaptations to climatic conditions. We suggest new directions for future studies involving this clade, in order to better understand its evolutionary history and generic circumscription.
Dark holograms and gravitational waves
Authors: Bigazzi Francesco , Caddeo Alessio , Cotrone Aldo L. , Paredes Angel
Published: April 2021

Abstract

Spectra of stochastic gravitational waves (GW) generated in cosmological first-order phase transitions are computed within strongly correlated theories with a dual holographic description. The theories are mostly used as models of dark sectors. In particular, we consider the so-called Witten-Sakai-Sugimoto model, a SU(N) gauge theory coupled to different matter fields in both the fundamental and the adjoint representations. The model has a well-known top-down holographic dual description which allows us to perform reliable calculations in the strongly coupled regime. We consider the GW spectra from bubble collisions and sound waves arising from two different kinds of first-order phase transitions: a confinement/deconfinement one and a chiral symmetry breaking/restoration one. Depending on the model parameters, we find that the GW spectra may fall within the sensibility region of ground-based and space-based interferometers, as well as of Pulsar Timing Arrays. In the latter case, the signal could be compatible with the recent potential observation by NANOGrav. When the two phase transitions happen at different critical temperatures, characteristic spectra with double frequency peaks show up. Moreover, in this case we explicitly show how to correct the redshift factors appearing in the formulae for the GW power spectra to account for the fact that adiabatic expansion from the first transition to the present times cannot be assumed anymore.