bluuebunny/crossref_metadata_2025_split huggingface dataset:
Helical Structures of Nylon‐Like Oligomers Consisting of 1,2‐Diamine and 1,2‐Dicarboxylic Acid Building Blocks Containing a Five‐Membered Ring Constraint
Authors: Choi Sunglim , Guzei Ilia A. , Kim Younghun , Kang Philjae , Choi Soo Hyuk 
Published: July 2021

AbstractA series of nylon‐like oligomers was synthesized, which consisted of alternating cyclic 1,2‐diamine and 1,2‐dicarboxylic acid building blocks with a five‐membered ring constraint. The nylon 2 4 oligomers are symmetric and display helical structures similar to the β‐peptide 12‐helix with intramolecular 12‐membered ring hydrogen bonds. The cyclopentane moiety allows each building block to promote 12‐helical folding. In addition, a tartaric acid derivative with the acetonide moiety increases the solubility of oligomers in common organic solvents and promotes helical folding.
Performance evaluation on the node mobility with respect to human driver behavior prediction in vehicular ad hoc network using adaptive deer hunting Optimized Link State Routing Protocol
Authors: Swamynathan Cloudin , Palanichamy Mohan Kumar , Jerald Arokia Renjit 
Published: July 2021

SummaryIn vehicular ad hoc network (VANET) broadcasting is considered as the critical area of research. The vehicles are connecting in an ad hoc manner to create a network of a wider range. In an intelligent transport system (ITS), with vehicle to vehicle (V2V) communication in the VANET is used to support the network backbone and which the accident prevention technique has been deployed for ensuring the road safety. The major reason for the road accident is the abnormal driving behavior of human drivers. The movement pattern of the vehicle is the main factor of the network topology so that the impact of human driving pattern influences the performance and behavior of the network. Driving behavior can be classified as reckless, normal, drunken, and fatigue driving. During driving, the behavior of human drivers was predicted in this paper, thereby providing the performance analysis on the mobility of the network. For the improvement of a driver behavior, the hybridized mega‐trend diffusion (MTD) with optimized deep belief network–sunflower optimization (DBN‐SFO) is used. Here, the network performance of the adaptive deer hunting Optimized Link State Routing Protocol (ADHOLSR) is analyzed in NS2 simulation platform.
Potential of nafimidone derivatives against co‐morbidities of epilepsy: In vitro, in vivo, and in silico investigations
Authors: Sari Suat , Barut Burak , Marcinkowska Monika , Sabuncuoğlu Suna , Avci Ahmet , Koçak Aslan Ebru , Özel Arzu , Siwek Agata 
Published: July 2021

AbstractNafimidone is known for its clinical antiepileptic effects and alcohol derivatives of nafimidone were reported be potent anticonvulsants. These compounds are structurally similar to miconazole, which is known to inhibit cholinesterases, protect neurons, and ameliorate cognitive decline. Herein, we aimed to reveal the potential of three nafimidone alcohol esters (5 g, 5i, and 5 k), which were previously reported for their anticonvulsant effects, against co‐morbidities of epilepsy such as inflammatory and neuropathic pain, cognitive and behavioral deficits, and neuron death, and understand their roles in related pathways such as γ‐butyric acid type A (GABAA) receptor and cholinesterases using in vitro, in vivo and in silico methods. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) test was used for cytotoxicity evaluation, hippocampal slice culture assay for neuroprotection, formalin test for acute and inflammatory pain, sciatic ligation for neuropathic pain, Morris water maze and open field locomotor tasks for cognitive and behavioral deficits, radioligand binding for GABAA receptor affinity, spectrophotometric methods for cholinesterase inhibition in vitro, and molecular docking in silico. The compounds were non‐toxic to fibroblast cells. 5 k was neuroprotective against kainic acid‐induced neuron death. 5i reduced pain response of mice in both the acute and the inflammatory phases. 5i improved survival upon status epilepticus. The compounds showed no affinity to GABAA receptor but inhibited acetylcholinesterase, 5 k also inhibited butyrylcholinesterase. The compounds were predicted to interact mainly with the peripheric anionic site of cholinesterase enzymes. The title compounds showed neuroprotective, analgesic, and cholinesterase inhibitory effects, thus they bear promise against certain co‐morbidities of epilepsy with neurological insults.
Linking ecology, morphology, and metabolism: Niche differentiation in sympatric populations of closely related species of the genusLittorina(Neritrema)
Authors: Maltseva Arina L. , Varfolomeeva Marina A. , Ayanka Roman V. , Gafarova Elizaveta R. , Repkin Egor A. , Pavlova Polina A. , Shavarda Alexei L. , Mikhailova Natalia A. , Granovitch Andrei I. 
Published: July 2021

AbstractDivergence of ecological niches in phylogenetically closely related species indicates the importance of ecology in speciation, especially for sympatric species are considered. Such ecological diversification provides an advantage of alleviating interspecies competition and promotes more efficient exploitation of environmental resources, thus being a basis for ecological speciation. We analyzed a group of closely related species from the subgenusNeritrema(genusLittorina, Caenogastropoda) from the gravel‐bouldery shores. In two distant sites at the Barents and Norwegian Sea, we examined the patterns of snail distribution during low tide (quantitative sampling stratified by intertidal level, presence of macrophytes, macrophyte species, and position on them), shell shape and its variability (geometric morphometrics), and metabolic characteristics (metabolomic profiling). The studied species diversified microbiotopes, which imply an important role of ecological specification in the recent evolution of this group. The only exception to this trend was the species pairL. arcana/L. saxatilis, which is specifically discussed. The ecological divergence was accompanied by differences in shell shape and metabolomic characteristics. Significant differences were found betweenL. obtusataversusL. fabalisandL. saxatilis/L. arcanaversusL. compressaboth in shell morphology and in metabolomes.L. saxatilisdemonstrated a clear variability depending on intertidal level which corresponds to a shift in conditions within the occupied microhabitat. Interestingly, the differences betweenL. arcana(inhabiting the upper intertidal level) andL. compressa(inhabiting the lower one) were analogous to those between the upper and lower fractions ofL. saxatilis. No significant level‐dependent changes were found between the upper and lower fractions ofL. obtusata, most probably due to habitat amelioration by fucoid macroalgae. All these results are discussed in the contexts of the role of ecology in speciation, ecological niche dynamics and conservatism, and evolutionary history of theNeritremaspecies.
Northward geographic diversification of a kleptoparasitic spider Argyrodes lanyuensis (Araneae, Theridiidae) from the Philippine Archipelago to Orchid Island
Authors: Responte Mae , Chiu Yi‐Fan , Peng Po , Brown Rafe M. , Dai Chia‐Yen , Su Yong‐Chao 
Published: July 2021

AbstractOceanic islands are unique geographic systems that promote local adaptations and allopatric speciation in many of their highly endemic taxa. This is a common case in the Philippine Archipelago, where numerous unrelated taxa on islands have been inferred to have diversified in isolation. However, few cases have been reported in invertebrates especially among parasitic organisms. Here, we tested for biogeographical structure in novel populations of the “generalist" kleptoparasitic spider, Argyrodes lanyuensis Yoshida, Tso & Severinghaus, 1998 in the Philippines. Results showed that, in addition to Orchid/Lanyu Island, this species has a wide geographic distribution in the Philippine Archipelago. The estimated divergence time of this lineage using the mitochondrial cytochrome oxidase 1 (mt‐CO1) suggests that this species diverged ca 3.12 MYA, during the Pliocene. Two reciprocal monophyletic clades were elucidated in A. lanyuensis, but with limited differentiation across Pleistocene Aggregate Island Complex (PAIC) boundaries and modern‐day islands. However, in our analyses of morphological variation, we identified two phenotypically differentiated units in males (Orchid Island, Taiwan + Luzon, Philippine PAIC populations vs. Palawan + West Visayan + Mindanao PAIC populations). We infer that this species diverged in the southern portion of the Philippine Archipelago and only recently colonized Orchid Island. Our study provides new information on the extensive distribution of A. lanyuensis outside Orchid Island, Taiwan, but we documented a very limited geographically associated genetic variation. Our study points to behavioral phenomena such as foraging behavior as essential contributor to the evolutionary process of species diversification, in contrast to the traditionally invoked geographic drivers of divergence.
Microgeographic evolution of metabolic physiology in a salamander metapopulation
Authors: Giery Sean T. , Drake Dana L. , Urban Mark C. 
Published: July 2021

AbstractThe Metabolic Theory of Ecology explains ecological variation spanning taxonomic organization, space, and time based on universal physiological relationships. The theory depends on two core parameters: the normalization constant, a mass‐independent measure of metabolic rate expected to be invariant among similar species, and the scaling coefficient, a measure of metabolic change with body mass commonly assumed to follow the universal 3/4 scaling law. However, emerging evidence for adaptive microevolution of metabolic rates led us to hypothesize that metabolic rate might exhibit evolved variation among populations on microgeographic scales. To evaluate our hypothesis, we explored evidence for evolved variation in the scaling coefficient and normalization constant within a spotted salamander (Ambystoma maculatum) metapopulation in Connecticut, USA. We measured standard metabolic rate in common‐garden raised spotted salamanders from 22 different populations and tested for the effects of six ecological variables suspected in advance to select for divergent physiology. We found that metabolic rate rose with body mass with a log‐log slope of 0.97 that was statistically different from the expected 3/4 scaling law. Although we found no evidence for interpopulation variation in the scaling coefficient, we found evidence for interpopulation variation in the normalization constants among populations. Metabolic variation was best explained by differences in population density among ponds. Our results provide mixed support for Metabolic Theory of Ecology assumptions about parameter invariance and illustrate how fundamental physiological processes such as metabolic rate can evolve across microgeographic spatial scales.
Tripartite legume–rhizobia–mycorrhizae relationship is influenced by light and soil nitrogen in Neotropical canopy gaps
Authors: Ficano Nikayla , Porder Stephen , McCulloch Lindsay A. 
Published: July 2021

AbstractPlants and their soil microbial symbionts influence ecosystem productivity and nutrient cycling, but the controls on these symbioses remain poorly understood. This is particularly true for plants in the Fabaceae family (hereafter legumes), which can associate with both arbuscular mycorrhizal fungi (AMF) and nitrogen (N) ‐fixing bacteria. Here we report results of the first manipulated field experiment to explore the abiotic and biotic controls of this tripartite symbiosis in Neotropical canopy gaps (hereafter gaps). We grew three species of Neotropical N‐fixing legume seedlings under different light (gap–full light, gap–shadecloth, and understory) and soil nitrogen (20 g N·m−2·yr−1 vs. 0 g N·m−2·yr−1) conditions across a lowland tropical forest at La Selva Biological Station, Costa Rica. We harvested the seedlings after 4 months of growth in the field and measured percent AMF root colonization (%AMF), nodule and seeding biomass, and seedling aboveground:belowground biomass ratios. Our expectation was that seedlings in gaps would grow larger and, as a result of higher light, invest more carbon in both AMF and N‐fixing bacteria. Indeed, seedlings in gaps had higher total biomass, nodule biomass (a proxy for N‐fixing bacteria investment) and rates of AMF root colonization, and the three were significantly positively correlated. However, we only found a significant positive effect of light availability on %AMF when seedlings were fertilized with N. Furthermore, when we statistically controlled for treatment, species, and site effects, we found %AMF and seedling biomass had a negative relationship. This was likely driven by the fact that seedlings invested relatively less in AMF as they increased in biomass (lower %AMF per gram of seedling). Taken together, these results challenge the long‐held assumption that high light conditions universally increase carbon investment in AMF and demonstrate that this tripartite symbiosis is influenced by soil nutrient and light conditions.
Donor‐Reactivity‐Controlled Sialylation Reactions
Authors: Asressu Kesatebrhan Haile , Chang Chun‐Wei , Lam Sarah , Wang Cheng‐Chung 
Published: July 2021

AbstractAlthough tremendous efforts have been made for the efficient preparation of sialosides, controlling the stereochemical outcome of sialylation reaction still remains one of the most challenging tasks due to the unique chemical structure of sialic acid. We developed a new strategy to statistically analyze the stereoselectivity of sialylation reactions on six types of p‐tolyl thiosialosides in NIS/TfOH system using Relative Reactivity Value (RRV) as the indicator. Analysis of the reaction mechanism showed the formation of the relatively stable glycosyl bromide and glycosyl chloride intermediates from halide‐ and triflate‐containing promotors in the absence of an acceptor. We found that the α/β‐stereoselectivity, yields, and intermediate changes were associated with their donor reactivity. These findings enable to tailor the most suitable building blocks for stereo‐controlled sialylation reactions.
One‐Pot Synthesis of α‐Diazo‐γ,δ‐unsaturated Esters as Versatile Building Blocks for Functionalized Dienes, Cyclopentenes, and 5,7‐Fused Bicycles
Authors: Russo Theo V. C. , Sá Marcus M. 
Published: July 2021

AbstractThe synthesis of novel allylic α‐diazo carbonyl compounds was achieved through a one‐pot strategy involving base‐catalyzed allylation of 1,3‐dicarbonyls with readily available allylic bromides followed by the deacylative diazo transfer reaction. Besides the broad substrate scope related to this method, other relevant features include the use of simple and inexpensive reagents, non‐toxic solvents and mild reaction conditions. The synthetic utility of these α‐diazo‐γ,δ‐unsaturated esters was further demonstrated through rhodium‐catalyzed transformations, where the type of product formed is dependent on both the substrate and catalyst employed. Thus, treating α‐diazo‐γ,δ‐unsaturated esters with catalytic Rh2(pfb)4 in acetonitrile under reflux resulted in a diastereoselective β‐hydride migration to give 2Z,4E‐dienes in good yields. On the other hand, the combination of Rh2(OAc)4 as the catalyst in toluene under reflux for 10 min led the aryl‐substituted diazo compounds to a regioselective intramolecular Buchner reaction to furnish 5,7‐fused bicyclic tetraenes in high yields, while the alkyl‐substituted analogues undergo intramolecular C–H insertion to give functionalized cyclopentenes of anti‐configuration.
Titanium Carbide (Ti3C2Tx) MXene Ornamented with Palladium Nanoparticles for Electrochemical CO Oxidation
Authors: Salah Belal , Eid Kamel , Abdelgwad Ahmed M. , Ibrahim Yasmeen , Abdullah Aboubakr M. , Hassan Mohammad K. , Ozoemena Kenneth I. 
Published: July 2021

AbstractTitanium carbide (Ti3C2Tx) MXene possesses various unique physicochemical and catalytic properties. However, the electrochemical CO oxidation performance is not yet addressed experimentally. Herein, Ti3C2Tx (TX=OH, O, and F) ordered and exfoliated two‐dimensional nanosheets ornamented with semi‐spherical palladium nanoparticles (2.5 Wt. %) with an average diameter of (10±1 nm) (denoted as Pd/Ti3C2Tx) is rationally designed for the electrochemical CO oxidation. The fabrication process is based on the selective chemical etching of Ti3AlC2 and delamination under sonication to form Ti3C2Tx nanosheets that are used as a substrate and reducing agent for supporting in situ growth of Pd nanoparticles via impregnation with Pd salt. Interestingly, Pd‐free Ti3C2Tx displayed inferior CO oxidation activity, while Pd/Ti3C2Tx enhanced the CO oxidation activity substantially. This is attributed to the combination of outstanding physicochemical properties of Ti3C2Tx and the catalytic merits of Pd nanoparticles.
Design of an acidic sulfonated mesoporous carbon catalyst for the synthesis of butyl levulinate from levulinic acid
Authors: Bakhtiari Behrokh , Najafi Chermahini Alireza , Babaei Zahra 
Published: July 2021

AbstractIn this work, the ordered mesoporous carbon CMK‐8 which has some advantages, including large specific pore volume, high surface area, and also its tunable pore size, was synthesized, then functionalized with various sulfonic acid groups and utilized as a heterogeneous catalyst in the esterification reaction of levulinic acid (LA) into n‐butyl levulinate (BL). The prepared catalysts were characterized using Fourier transformed‐infrared spectroscopy, N2 adsorption–desorption, small‐angle X‐ray diffraction analysis, elemental analysis, transmission electron microscopy, field emission scanning electron microscope, thermal gravimetric analysis, energy dispersive X‐ray spectroscopy, and elemental mapping. The important parameters such as reaction temperature, reaction time, catalyst amount, and LA to n‐BuOH molar ratio were investigated by Taguchi experimental design. Maximum BL yield (75.1%) and LA conversion (95%) were obtained with CMK‐8‐SO3H catalyst under optimum reaction conditions: reaction temperature 130°C, reaction time 10 h, catalyst dosage 0.015 g, and LA to n‐BuOH molar ratio 1:10. Among the entire parameters, LA to n‐BuOH molar ratio followed by the reaction temperature, catalyst concentration, and reaction time have the most influence on BL yield. Finally, the regeneration and reusability of the CMK‐8‐SO3H catalyst were studied, and the recovered catalyst showed high stability and activity after four runs.
ω3PUFAs improve hepatic steatosis in postnatal overfed rats and HepG2 cells by inhibiting acetyl‐CoA carboxylase
Authors: Zhou Nan , Du Susu , Dai Yanyan , Yang Fan , Li Xiaonan 
Published: July 2021

AbstractPostnatal overfeeding can lead to persistent increases in hepatic lipid synthesis and the risk of nonalcoholic fatty liver disease (NAFLD) in adulthood. The ω3 polyunsaturated fatty acids (ω3PUFAs) exhibit beneficial effects on NAFLD. Here, we employed a rat model and an in vitro HepG2 cell model to investigate whether fish oil (FO) affects hepatic lipid synthesis due to postnatal overfeeding. Male Sprague‐Dawley were divided into litter sizes of three (small litters, SLs) or 10 (normal litters, NLs) on postnatal day 3 and were fed standard chow or FO diet beginning on postnatal week 3 to generate NL, SL, NL‐FO, and SL‐FO groups. The results indicated that the FO diet reduced the postnatal overfeeding‐induced body weight gain and NAFLD characteristics (such as serum and liver triglyceride (TG) and hepatic steatosis). In addition, FO restored the expression of hepatic lipid metabolism‐related genes (including SCD1, FASN, CPT1, LPL, ACC, and SREBP‐1c) in SL‐FO rats. Specifically, the activity and expression pattern of ACC were consistent with SREBP‐1c. Furthermore, HepG2 cells were treated with oleic acid (OA), followed by eicosapentenoic acid (EPA), with or without SREBP‐1c siRNA. The cellular lipid droplets, TG content, and the expression of ACC (by 75%) and SREBP‐1c (by 45%) were increased by OA stimulation (p < .05), which was inhibited by EPA treatment. However, the effect of EPA treatment was abolished when SREBP‐1c was silenced. In conclusion, ω3PUFAs‐rich diet may be an effective way to reverse the developmental programming of hepatic lipid synthesis, at least partially, by inhibiting ACC through modulating SREBP‐1c.
Parameterizing standard measures of income and health inequality using choice experiments
Authors: Hardardottir Hjördis , Gerdtham Ulf‐G , Wengström Erik 
Published: July 2021

AbstractWhen measuring inequality using conventional inequality measures, ethical assumptions about distributional preferences are often implicitly made. In this paper, we ask whether the ethical assumptions underlying the concentration index for income‐related health inequality and the Gini index for income inequality are supported in a representative sample of the Swedish population using an internet‐based survey. We find that the median subject has preferences regarding income‐related health inequality that are in line with the ethical assumptions implied by the concentration index, but put higher weight on the poor than what is implied by the Gini index of income inequality. We find that women and individuals with a poorer health status put higher weight on the poor than men and healthier individuals. Ethically flexible inequality measures, such as the s‐Gini index and the extended concentration index, imply that researchers have to choose from a toolbox of infinitely many inequality indices. The results of this paper are indicative of which indices (i.e. which parameter values) reflect the views of the population regarding how inequality should be defined.
Effect of heat source on Rayleigh–Bénard convection in rotating viscoelastic liquids
Authors: Jayalatha G. , Suma N. 
Published: July 2021

AbstractThe influence of heat sources on instability in rotating viscoelastic liquids is studied. Linear stability analysis is done using normal modes. Computations are done for 10 boundary combinations and the results reveal that convection manifests via the oscillatory mode in this case. The critical values of the oscillatory and stationary instability have been studied. The results indicate individual stabilizing influences of rotation and strain retardation along with heat source in the case of free isothermal boundary conditions. It has quite unpredictable influences on the system stability in all the other boundary conditions for the chosen parameters. By suitable limiting processes, results pertaining to Oldroyd liquid B will lead to those of Maxwell, Newtonian, and Rivlin–Ericksen liquids. The problem finds applications in a working media consisting of viscoelastic liquids with nonisothermal systems.