bluuebunny/crossref_metadata_2025_split huggingface dataset:
Not Carbon s–p Hybridization, but Coordination Number Determines C−H and C−C Bond Length
Authors: Vermeeren Pascal , van Zeist Willem‐Jan , Hamlin Trevor A. , Fonseca Guerra Célia , Bickelhaupt F. Matthias 
Published: January 2021

AbstractA fundamental and ubiquitous phenomenon in chemistry is the contraction of both C−H and C−C bonds as the carbon atoms involved vary, in s–p hybridization, along sp3 to sp2 to sp. Our quantum chemical bonding analyses based on Kohn–Sham molecular orbital theory show that the generally accepted rationale behind this trend is incorrect. Inspection of the molecular orbitals and their corresponding orbital overlaps reveals that the above‐mentioned shortening in C−H and C−C bonds is not determined by an increasing amount of s‐character at the carbon atom in these bonds. Instead, we establish that this structural trend is caused by a diminishing steric (Pauli) repulsion between substituents around the pertinent carbon atom, as the coordination number decreases along sp3 to sp2 to sp.
Influence of Pore Structure and Metal‐Node Geometry on the Polymerization of Ethylene over Cr‐Based Metal–Organic Frameworks
Authors: Jongkind Maarten K. , Rivera‐Torrente Miguel , Nikolopoulos Nikolaos , Weckhuysen Bert M. 
Published: January 2021

AbstractMetal–organic frameworks (MOFs) have received increasing interest as solid single‐site catalysts, owing to their tunable pore architecture and metal node geometry. The ability to exploit these modulators makes them prominent candidates for producing polyethylene (PE) materials with narrow dispersity index (Ð) values. Here a study is presented in which the ethylene polymerization properties, with Et2AlCl as activator, of three renowned Cr‐based MOFs, MIL‐101(Cr)‐NDC (NDC=2,6‐dicarboxynapthalene), MIL‐53(Cr) and HKUST‐1(Cr), are systematically investigated. Ethylene polymerization reactions revealed varying catalytic activities, with MIL‐101(Cr)‐NDC and MIL‐53(Cr) being significantly more active than HKUST‐1(Cr). Analysis of the PE products revealed large Ð values, demonstrating that polymerization occurs over a multitude of active Cr centers rather than a singular type of Cr site. Spectroscopic experiments, in the form of powder X‐ray diffraction (pXRD), UV/Vis‐NIR diffuse reflectance spectroscopy (DRS) and CO probe molecule Fourier transform infrared (FTIR) spectroscopy corroborated these findings, indicating that indeed for each MOF unique active sites are generated, however without alteration of the original oxidation state. Furthermore, the pXRD experiments indicated that one major prerequisite for catalytic activity was the degree of MOF activation by the Et2AlCl co‐catalyst, with the more active materials portraying a larger degree of activation.
Fluorinated Rings: Conformation and Application
Authors: Mondal Rajarshi , Agbaria Mohamed , Nairoukh Zackaria 
Published: January 2021

AbstractThe introduction of fluorine atoms into molecules and materials across many fields of academic and industrial research is now commonplace, owing to their unique properties. A particularly interesting feature is the impact of fluorine substitution on the relative orientation of a C−F bond when incorporated into organic molecules. In this Review, we will be discussing the conformational behavior of fluorinated aliphatic carbo‐ and heterocyclic systems. The conformational preference of each system is associated with various interactions introduced by fluorine substitution such as charge‐dipole, dipole‐dipole, and hyperconjugative interactions. The contribution of each interaction on the stabilization of the fluorinated alicyclic system, which manifests itself in low conformations, will be discussed in detail. The novelty of this feature will be demonstrated by presenting the most recent applications.
Endothelial NADPH oxidase 4 protects against angiotensin II‐induced cardiac fibrosis and inflammation
Authors: Wang Minshu , Murdoch Colin E. , Brewer Alison C. , Ivetic Aleksandar , Evans Paul , Shah Ajay M. , Zhang Min 
Published: January 2021

AbstractAimsEndothelial activation and inflammatory cell infiltration have important roles in the development of cardiac fibrosis induced by renin–angiotensin system activation. NADPH oxidases (Nox proteins) are expressed in endothelial cells (ECs) and alter their function. Previous studies indicated that Nox2 in ECs contributes to angiotensin II (AngII)‐induced cardiac fibrosis. However, the effects of EC Nox4 on cardiac fibrosis are unknown.Methods and resultsTransgenic (TG) mice overexpressing endothelial‐restricted Nox4 were studied alongside wild‐type (WT) littermates as controls. At baseline, Nox4 TG mice had significantly enlarged hearts compared with WT, with elongated cardiomyocytes (increased by 18.5%, P < 0.01) and eccentric hypertrophy but well‐preserved cardiac function by echocardiography and in vivo pressure–volume analysis. Animals were subjected to a chronic AngII infusion (AngII, 1.1 mg/kg/day) for 14 days. Whereas WT/AngII developed a 2.1‐fold increase in interstitial cardiac fibrosis as compared with WT/saline controls (P < 0.01), TG/AngII mice developed significant less fibrosis (1.4‐fold increase, P > 0.05), but there were no differences in cardiac hypertrophy or contractile function between the two groups. TG hearts displayed significantly decreased inflammatory cell infiltration with reduced levels of vascular cell adhesion molecule 1 in both the vasculature and myocardium compared with WT after AngII treatment. TG microvascular ECs stimulated with AngII in vitro supported significantly less leukocyte adhesion than WT ECs.ConclusionsA chronic increase in endothelial Nox4 stimulates physiological cardiac hypertrophy and protects against AngII‐induced cardiac fibrosis by inhibiting EC activation and the recruitment of inflammatory cells.
Unveiling the Zirconium and Hafnium Speciation in Fluoride‐Nitric Acid Solutions by Paper Spray Ionization Mass Spectrometry Combined with DFT Calculations
Authors: Bertoli Alexandre C. , Miguita Ana Gabriella C. , Mingote Raquel M. , Augusti Rodinei , Duarte Hélio A. 
Published: January 2021

AbstractPaper spray ionization mass spectrometry (PSI‐MS) was used to detect a variety of species of hafnium and zirconium present in an aqueous acid solution containing NO3− and F− anions. This solution mimetics the acid waters used in separation/extraction processes. Hence, the information provided by PSI‐MS is combined with the results achieved from DFT calculations to confirm the nature and stability of each species. In the adopted experimental conditions, Zr(IV) appears coordinated with F−, NO3− and H2O to generate mainly the dimer [Zr2F3OH(NO3)2(H2O)5]2+, among other complexes, with remarkable thermodynamic stability (−48.7 kcal mol−1). On the other hand, Hf(IV) emerges predominantly coordinated with NO3− and F− anions. The hafnium monomers [HfF4NO3]− and [HfF3(NO3)2]− have thermodynamic stability related to the electron pairing of the valence layer. In the gas phase, the fluoroanions of Zr(IV) demonstrated a high electronic affinity and free energy via DFT (−156.7 kcal mol−1) correlating thermodynamic stability to the experimental (−47 kcal mol−1), for the formation reaction of [ZrF5]−. Besides, the presence of fluoride and nitrate in the reaction mixture induces the formation of dimers connected in μ2‐F bridges, with coordination 7 and 8 of the central atom. Finally, the results described herein are promising studies of chemical speciation of cationic metals in an aqueous environment, a challenging subject whose importance will grow in the coming years.
Synthesis and Liquid Crystalline Self‐Assembly of Concave Diindoles with a Hydropentalene Core
Authors: Bühlmeyer Andrea , Ehni Philipp , Ullmann Dustin , Frey Wolfgang , Baro Angelika , Laschat Sabine 
Published: January 2021

AbstractFischer indole reaction of Weiss diketone with 4‐bromophenylhydrazine provided the 2,8‐dibromo‐hexahydropentaleno[2,1‐b:5,4‐b’]diindole key intermediate, which was converted to the target compounds by N‐protection/Suzuki cross‐coupling. Variation of protecting groups, mesogenic units, and their alkoxy substitution gave calamitic diindole mesogens. Both N‐protection and alkoxy chain influenced the mesomorphic properties of phenyl diindoles. Among the differently N‐protected derivatives only ethylcarbamate‐protected ones formed enantiotropic mesophases. Mesophase range and type were controlled by the chain lengths: chains≤C12 gave nematic (N) phases, diindoles with side chains≥C14 formed additional lower temperature smectic (SmA) phases. Irrespective of the chain lengths 4′‐alkyloxybiphenyl diindoles formed N and SmA phases upon first heating but tended to decomposition below their clearing points. X‐ray crystal structure analysis of bis(4′‐decyloxy)biphenyl diindole reveals that in the solid‐state the folding angle of the hydropentalene core caused an almost perpendicular orientation of the two indole/biphenyl parts with respect to each other.
The In Vitro Proinflammatory Properties of Water Accommodated Sediment Extracts from a Creosote-Contaminated US Environmental Protection Agency Superfund Site
Authors: Silva Rayna A. , Di Giulio Richard T. , Rice Charles D. 
Published: January 2021

Abstract
The southern branch of the Elizabeth River near Portsmouth, Virginia, USA, is one of the most creosote-polluted subestuaries in North America and the former location of the Atlantic Wood US Environmental Protection Agency Superfund site. We previously demonstrated that adult Atlantic Wood killifish collected in situ had severe hepatic lesions, including hepatoblastoma and hepatocellular carcinoma, as well as suppressed circulating antibody responses compared to a historical reference site. Moreover, several innate immune functions were higher in Atlantic Wood fish, including elevated expression of hepatic cyclooxygenase-2 (COX-2), suggesting a proinflammatory environment. To further examine the potential of Atlantic Wood contaminants to modulate innate immune function(s), the present study used RAW264.7 mouse macrophages as an in vitro model to develop new approach methodologies for rapid screening. Lipopolysaccharide (LPS)–stimulated nitric oxide secretion by macrophages is a rapid, sensitive, and predictive in vitro system for screening potentially immunotoxic contaminants as single compounds or as complex mixtures. Compared to the reference site, filter-sterilized Atlantic Wood sediment extracts (water accommodated fractions) induced nitric oxide and IL-6 secretion as well as inducible nitric oxide synthase and COX-2 proteins at levels comparable to or higher than those induced by LPS treatments alone. Extracts also increased phagocytic activity by macrophages. Using a limulus lysate assay, we show that bacterial endotoxin levels in Atlantic Wood extracts are higher than in reference extracts and that polymyxin-B chelation ameliorates proinflammatory effects. These findings illuminate the reality of sediment constituents other than toxic compounds previously associated with developmental abnormalities and carcinogenesis in killifish from the Atlantic Wood site. Perhaps these data also suggest the presence of contaminant-adapted consortia of sediment microbes at many heavily polluted sites worldwide compared to less contaminated sites. Environ Toxicol Chem 2021;40:1576–1585. © 2021 SETAC
Therapeutic perspective of thymoquinone: A mechanistic treatise
Authors: Butt Masood Sadiq , Imran Muhammad , Imran Ali , Arshad Muhammad Sajid , Saeed Farhan , Gondal Tanweer Aslam , Shariati Mohammad Ali , Gilani Syed Amir , Tufail Tabussam , Ahmad Ishtiaque , Rind Nadir Ali , Mahomoodally Mohamad Fawzi , Islam Saiful , Mehmood Zaffar 
Published: January 2021

AbstractThe higher utilization of fruits and vegetables is well known to cure human maladies due to the presence of bioactive components. Among these compounds, thymoquinone, a monoterpene and significant constituent in the essential oil of Nigella sativa L., has attained attention by the researchers due to their pharmacologies perspectives such as prevention from cancer, antidiabetic and antiobesity, prevention from oxidative stress and cardioprotective disorder. Thymoquinone has been found to work as anticancer agent against different human and animal cancer stages including propagation, migration, and invasion. Thymoquinone as phytochemical also downregulated the Rac1 expression, mediated the miR‐34a upregulation, and increased the levels of miR‐34a through p53, as well as also regulated the pro‐ and antiapoptotic genes and decreased the phosphorylation of NF‐κB and IKKα/β. In addition, thymoquinone also lowered the metastasis and ERK1/2 and PI3K activities. The present review article has been piled by adapting narrative review method and highlights the diverse aspects of thymoquinone such as hepatoprotective, anti‐inflammatory, and antiaging through various pathways, and further utilization of this compound in diet has been proven effective against different types of cancers.
A numerical comparison among different water‐based hybrid nanofluids on their influences on natural convection heat transfer in a triangular solar collector for different tilt angles
Authors: Prince Hasib A. , Rozin Enamul H. , Chowdhury Emdadul H. , Redwan Didarul A. , Mamun Mohammad A. H. 
Published: January 2021

AbstractNatural convection inside a triangular solar collector is investigated numerically for different nanofluids and hybrid nanofluids in this study. The individual effects of Al2O3–water, carbon nanotubes (CNT)–water, and Cu–water nanofluids are observed for different solid volume fractions of nanoparticles (0%–10%). Three types of hybrid nanofluids are prepared using different ratios of Al2O3, CNT, and Cu nanoparticles in water. A comparison is made varying the Rayleigh numbers within laminar range (103–106) for different tilt angles (0°, 30°, 60°, and 90°) of the solar collector. The inclined surface of the triangular solar collector is isothermally cold and the bottom wall (absorber plate) is isothermally hot, whereas the vertical wall with respect to the absorber plate is considered adiabatic. Average Nusselt numbers along the hot wall for different parameters are observed. Streamlines and isotherm contours are also plotted for different cases. Dimensionless governing Navier–Stokes and thermal energy conservation equations are solved by Galerkin weighted residual finite element method. Better convective heat transfer is found for higher Rayleigh number, solid volume fraction, and tilt angle. In the case of hybrid nanofluid, increasing the percentage of the nanoparticle that gives better heat transfer performance individually results in enhancing natural convection heat transfer inside the enclosure.
Effect of necessity‐concern framework and polypharmacy on treatment adherence in psychiatric patients. Comparing an Argentinian with a Spanish sample
Authors: De las Cuevas Carlos , Villasante‐Tezanos Alejandro G. , Motuca Mariano , de Leon Jose 
Published: January 2021

AbstractObjectiveWe aimed to replicate a prior Spanish study of medication adherence where logistic regression models provided highly significant odds ratios (ORs) for three continuous scores: necessity, concern and the necessity‐concern differential, and a dichotomous variable: skeptical attitude. Adherence ORs in the necessity‐concern framework were very strong in patients taking five or six medications.MethodsThe sample comprised consecutive adult psychiatric outpatients in Mendoza, Argentina. The necessity‐concerns framework was assessed using a subscale of the Beliefs about Medicines Questionnaire. Adherence (yes/no) to prescribed psychiatric medications was assessed by the Sidorkiewicz adherence tool.ResultsWhen compared with the Spanish sample, the Argentinian group (508 patients with 875 medications) was characterized by: (1) significantly stronger adherence ORs with the necessity‐concern framework, (2) significantly lower number of medications per patient and percentage of patients with marked psychiatric polypharmacy (≥4 medications), (3) though a higher number of medications still was significantly associated with poor adherence.ConclusionsThe Argentinian sample replicated the previous finding that patient beliefs regarding necessity and concern were associated with poor adherence to prescribed medications. Polypharmacy had an additive role decreasing adherence in both samples. In both samples, when prescribed ≥4 psychiatric medications, patients reported adherence to only two‐third of the medications.
Surface water‐groundwater exchange dynamics in buried‐valley aquifer systems
Authors: Wallace Corey D. , Soltanian Mohamad Reza 
Published: January 2021

AbstractGroundwater is a primary source of drinking water worldwide, but excess nutrients and emerging contaminants could compromise groundwater quality and limit its usage as a drinking water source. As such contaminants become increasingly prevalent in the biosphere, a fundamental understanding of their fate and transport in groundwater systems is necessary to implement successful remediation strategies. The dynamics of surface water‐groundwater (hyporheic) exchange within a glacial, buried‐valley aquifer system are examined in the context of their implications for the transport of nutrients and contaminants in riparian sediments. High conductivity facies act as preferential flow pathways which enhance nutrient and contaminant delivery, especially during storm events, but transport throughout the aquifer also depends on subsurface sedimentary architecture (e.g. interbedded high and low conductivity facies). Temperature and specific conductance measurements indicate extensive hyporheic mixing close to the river channel, but surface water influence was also observed far from the stream‐aquifer interface. Measurements of river stage and hydraulic head indicate that significant flows during storms (i.e., hot moments) alter groundwater flow patterns, even between consecutive storm events, as riverbed conductivity and, more importantly, the hydraulic connectivity between the river and aquifer change. Given the similar mass transport characteristics among buried‐valley aquifers, these findings are likely representative of glacial aquifer systems worldwide. Our results suggest that water resources management decisions based on average (base) flow conditions may inaccurately represent the system being evaluated, and could reduce the effectiveness of remediation strategies for nutrients and emerging contaminants.
Assessment on micronutrient concentration after reclaimed water irrigation: A CASE study in green areas of Madrid*
Authors: Zalacáin David , Sastre‐Merlín Antonio , Martínez‐Pérez Silvia , Bienes Ramón , García‐Díaz Andrés 
Published: January 2021

AbstractThe use of reclaimed water to cope with water scarcity has become one of the main alternative resources in water‐deficit countries. Reclaimed water represents a significant component in integrated water resources management in the city of Madrid (Spain). Madrid City Council replaced the usual drinking water irrigation system by a reclaimed water one. This study assessed the effects of reclaimed water irrigation on micronutrient concentration (B, Cu, Fe, Mn and Zn) in the soil–plant system of two urban green areas in Madrid. Results showed that reclaimed water used in Madrid was adequate for irrigation regarding the studied micronutrients. Nevertheless, micronutrient concentration were slightly higher in reclaimed water than in drinking water. Soil organic matter (SOM) and pH had strong influence in some of the micronutrient concentrations in soils and in its bioavailability and transference to cedars (SOM ↔ B Soil, Cu Soil, Fe Soil; pH ↔ B Soil, Fe Soil, Mn Soil). There was no significant correlation between micronutrient concentration in irrigation water and in cedar leaves. Thus, foliar concentration of the studied micronutrients did not exceed toxic limits, even after 15 years of reclaimed water irrigation. Moreover, despite one park was irrigated with reclaimed water 10 years more than the other, reclaimed water irrigation plots did not show major differences in micronutrient concentration between the two parks.
Sesquiterpenoid bilobalide inhibits gastric carcinoma cell growth and induces apoptosis both in vitro and in vivo models
Authors: Liu Jinglei , Geng Zhen , Zhang Yingying , Alharbi Sulaiman Ali , Shi Yulong 
Published: January 2021

AbstractGastric carcinoma is one of the most aggressive types of cancer that ranks fifth among all cancer incidences and third in cancer mortality. As it exhibits a prolonged asymptomatic condition and high recurrence rate, it is a great challenge to treat gastric cancer. Traditional medicine that utilizes herbal phytochemicals to treat various diseases is a potent alternative for current allopathic treatment. Hence, we evaluated the potency of a phytochemical bilobalide for treating gastric cancer in in vitro and in vivo models. Bilobalide, a sesquiterpenoid, is present in the Ginkgo bilobaplant that belongs to the family of Ginkgoaceae. The cytotoxicity effect of bilobalide was evaluated in both gastric cancer (AGS) cells and normal gastric epithelial cells. Apoptosis‐inducing property of bilobalide against the AGS cell line was analyzed with different fluorescent staining techniques and terminal deoxynucleotidyl transferase dUTP nick‐end labeling assay, and cell cycle analysis was carried out by flow cytometry. The in vivo studies were assessed withN‐methyl‐N‐nitrosourea (MNU)‐induced gastric cancer in rats. Serum‐specific gastric markers were quantified and histopathological analysis of stomach tissue was performed. The expression of target‐signaling molecules was analyzed by a reverse‐transcription polymerase chain reaction. The in vitro results proved that bilobalide effectively suppressed the AGS cell growth and induced cell death by nuclear damage and apoptosis induction. The bilobalide treatment effectively arrested the cell cycle of AGS cells via inhibiting the PI3K‐signaling pathway. Our in vivo results also confirmed that the bilobalide persuasively inhibited the MNU‐induced gastric carcinoma via inhibiting the thioredoxin‐fold family proteins and inflammatory markers' expression. Overall, our results authentically prove that bilobalide possesses therapeutic potency to cure gastric carcinoma.
Scutebarbatine A induces cytotoxicity in hepatocellular carcinoma via activation of the MAPK and ER stress signaling pathways
Authors: Feng Pan‐pan , Qi You‐kun , Li Na , Fei Hong‐rong 
Published: January 2021

AbstractScutebarbatine A (SBT‐A), a diterpenoid alkaloid found in the root ofScutellaria barbataD. Don, has been reported to induce the apoptosis of A549 cells. In this study, we investigated the antitumor activity of SBT‐A in human hepatocellular carcinoma (HCC) cells and the potential underlying mechanisms. Our results showed that SBT‐A inhibited the growth of HCC cells in a dose‐dependent manner. SBT‐A treatment caused cell cycle arrest and decreased the expression of cyclin B1, cyclin D1, p‐Cdc2, and p‐Cdc25C. SBT‐A triggered cell apoptosis via a caspase‐dependent pathway, and cell viability was partially restored by pretreatment with the pan‐caspase inhibitor Z‐VAD‐FMK. In HCC cells, treatment with SBT‐A increased the phosphorylation of extracellular signal‐regulated kinase 1 and 2 (ERK1/2), c‐Jun N‐terminal kinase 1 and 2 (JNK1/2), and p38 mitogen‐activated protein kinase (p38 MAPK). Moreover, SBT‐A activated endoplasmic reticulum (ER) stress through the upregulation of protein kinase RNA‐like ER kinase (PERK), activating transcription factor 4 (ATF‐4), and CCAAT‐enhancer‐binding protein (C/EBP) homologous protein (CHOP). Our data indicate that SBT‐A inhibits the proliferation of HCC cells and triggers their apoptosis via the activation of MAPK and ER stress. SBT‐A is a potential agent for the treatment of HCC.