bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational modelling identifies key determinants of subregion-specific dopamine dynamics in the striatum
Authors: Ejdrup Aske L , Dreyer Jakob K , Lycas Matthew D , Jørgensen Søren H , Robbins Trevor W , Dalley Jeffrey W , Herborg Freja , Gether Ulrik
Published: February 2025

Striatal dopamine (DA) release regulates reward-related learning and behavioural activation and is believed to consist of a short-lived
phasic
and continuous
tonic
component. Here, we build a three-dimensional model of extracellular DA dynamics in dorsal (DS) and ventral striatum (VS) that include tens of thousands of DA release sites. The model predicts rapid dynamics in DS with little-to-no basal DA, and much slower dynamics in the VS enabling build-up of a
tonic
DA level. These regional differences do not primarily reflect different release phenomena but rather arise from differential dopamine transporter (DAT) activity. Interestingly, our simulations posit prevalent nanoclustering of DAT as a possible regulator of this activity. Receptor binding simulations show that D1 receptor occupancy follows extracellular DA concentration with millisecond delay, while D2 receptors integrate DA signal over seconds. Summarized, our model distills recent experimental observations into a computational framework that challenge prevailing paradigms of striatal DA signalling.
Old age variably impacts chimpanzee engagement and efficiency in stone tool use
Authors: Howard-Spink Elliot , Matsuzawa Tetsuro , Carvalho Susana , Hobaiter Catherine , Almeida-Warren Katarina , Gruber Thibaud , Biro Dora
Published: February 2025

We know vanishingly little about how long-lived apes experience senescence in the wild, particularly with respect to their foraging behaviors, which are essential for survival. Some wild apes use tools during foraging and, given the additional cognitive and physical challenges presented by tool use, we predict that such behaviors are at a heightened risk of senescence. However, until the present, longitudinal analysis of the effects of progressive aging on wild ape tool-use behaviors has not been possible due to a lack of available data. In response to this research gap, we sampled data from a longitudinal video archive that contained footage of wild chimpanzees engaging in one of their most complex forms of tool use - the cracking of hard-shelled nuts with hammers and anvil stones, termed
nut cracking
- at an ‘outdoor laboratory’ at Bossou, Guinea. By sampling data over a 17-year period, we describe how progressive old age influences the extent to which wild chimpanzees engage with – and efficiently perform – nut cracking. With increasingly old age, chimpanzees began attending experimental nut cracking sites less frequently than younger individuals. Several elderly chimpanzees exhibited reductions in efficiency across multiple components of nut cracking, including taking more time to select stone tools prior to use, and taking longer to crack open nuts and consume the associated pieces of kernel. Two chimpanzees also began using less streamlined behavioral sequences to crack nuts, including a greater number of actions (such as more numerous strikes of the hammer stone). Most notably, we report interindividual variability in the extent to which tool-use behaviors senesced during aging – ranging from small to profound reductions in tool engagement and efficiency – as well as differences in the specific aspects of nut cracking behaviors which senesced for each individual. We discuss the possible causes of these changes with reference to research into senescence in captive primates, and provide future directions for research of primate aging in both captive and wild settings.
Spatial Distribution, Isolation, and Characterization of Morphological Variants of the Fusarium Wilt Pathogen in Brinjal Across Andhra Pradesh and Tamil Nadu, India
Authors: Reddy Mule Harindra , Sundaramoorthy S.
Published: February 2025

Fusarium wilt, caused by various Fusarium species, is a devastating disease of brinjal (Solanum melongena) leading to substantial yield losses in major production regions. This study aimed to assess the prevalence of Fusarium wilt in Tamil Nadu and Andhra Pradesh during 2024. A comprehensive survey across brinjal-growing regions, including Chittoor, Kurnool, Guntur, Salem, Dindigul, Krishnagiri, and Cuddalore, revealed varying disease incidence. Hosur (Tamil Nadu) exhibited the highest percent disease incidence (PDI) at 56.45%, followed by Madanapalli (Andhra Pradesh) at 54.67%. Pathogen isolation and identification using the tissue segment method confirmed Fusarium sp. as the primary causal agent. Morphological characterization revealed significant variations among isolates in colony shape, conidial diameters, and growth patterns, indicating a heterogeneous Fusarium population across the investigated locations. To lessen the effect of Fusarium wilt on brinjal output, these results highlight the vital necessity for ongoing monitoring, precise pathogen identification, and the creation of integrated management techniques such resistant variety breeding.
Impact of Climate Change on Yield of Major Cereals in India and Nepal: A Micro Regional Analysis
Authors: Ghimire Milan , Badal P.S
Published: February 2025

Rupandehi and Varanasi districts are located in the tropical region of Nepal and India. As a result, both districts experience warm temperature typical of this climate. The aim of the research is to study the effect of different climatic variables on selected cereals. The study examines the trend of three main climatic variable (e.g. maximum temperature, minimum temperature and rainfall) for the two districts of two different country India and Nepal, by using the time series data for the period 1980-2016 A.D and accesses the relationship between the variables and the yield of two major cereals rice and wheat crops. Multiple linear regression analysis model used in this study. The result from the finding reveals that impact of climatic variables on yield of rice and wheat is more in Rupandehi district 48% in rice and 16% in wheat. Where as in Varanasi district decrease in rice yield by 6.5% and wheat by 21%. For this result adverse effect of maximum temperature and rainfall are responsible in kharif season. The study also evaluates the local knowledge and resource-based adaptation techniques followed by the farmers against climate change.
Effect of Different Wrapping Materials on Shelf-life of Papaya (Carica papaya L.) cv. Red Lady
Authors: Kumar Bharat , Deshmukh Umesh B. , Sharma S.P. , Singh Jitendra , Nishad Dikeshwar , Gupta Nikhil , Singh Shivnandan
Published: February 2025

The current study conducted during the year 2023 at Fruit Science Lab in Pt. K.L.S. College of Horticulture and Research Station, Rajnandgaon, (C.G.). The experiment of completely randomized design and replicated thrice with a total of 07 treatments where (T1) newspaper, (T2) tissue straw, (T3) paddy straw, (T4) foam net, (T5) polythene, (T6) CFB (corrugated fiber board box) and (T7) control. T5 polythene exhibited better performance in relation to most of the parameters like Physiological loss in weight (%) (2.73, 5.98, 8.84 and 10.41), Percentage of ripening (%) (25.74, 33.51, 47.73 and 57.37), Ascorbic acid (%) (34.16, 53.51, 67.55 and 56.12), TSS (0B) (7.53, 12.54, 16.6 and 13.43), fruit length (cm) (22.23, 21.73, 21.30 and 20.29), total sugar (%) (5.85, 9.95, 11.42 and 10.24), reducing sugar (%) (4.40, 6.83, 9.68 and 7.65), acidity (%) (0.18, 0.12, 0.11 and 0.06) at 3, 6, 9 and 12 days respectively. Based on outcomes of present studies, it can be concluded that the papaya fruits wrapped in polythene exhibited superiority with respect to shelf life and quality of papaya. Hence the treatment T5 (polythene) may be recommended for wrapping materials for improvement of quality parameters of papaya cv. red lady.
A Spatial Statistical Approach to Geomorphotectonics of the Karbi-Shillong Plateau Outlier
Authors: Roy Amitabha
Published: February 2025

This study explores the geomorphotectonics of the Karbi-Shillong Plateau outlier in northeast India through a
spatial statistical approach. Spatial statistics, encompassing pattern analysis and model predictions based on
geographic relationships, reveal significant insights into geological structures and their dynamics. The KarbiShillong Plateau, distinct from the main Indian peninsula, exemplifies geological outliers characterized by
unique tectonic settings influenced by compressive forces and numerous faults. Positioned away from the
central Peninsular Block, its geological composition includes Proterozoic and Mesozoic-Tertiary rocks,
emphasizing its complex evolution. This research challenges the notion of the plateau as merely an extension of
the Indian peninsula, instead highlighting its identity as a significant and separate geological entity within the Great Himalayan system. Ultimately, the study advocates for a nuanced understanding of such outliers, underlining their critical role in regional geoscience and tectonic research.
A multifunctional calmodulin‐dependent protein kinase
Authors: McGuinness Teresa L. , Lai Yvonne , Greengard Paul , Woodgett James R. , Cohen Philip
Published: July 2002

Calmodulin‐dependent glycogen synthase kinase isolated from skeletal muscle and synapsin I kinase II isolated from brain have several properties that are very similar. These properties include: substrate and site‐specificities, immunological cross‐reactivity, and phosphopeptide maps following limited proteolysis. Both enzymes phosphorylate a wide variety of substrate proteins. The two kinases may represent different isozymes of a multifunctional calmodulin‐dependent protein kinase that mediates many of the actions of Ca2+ in various tissues. Therefore, we propose the name ‘calmodulin‐dependent multi‐protein kinase’ for this broad specificity enzyme.
An activator of protein kinase C (phorbol‐12‐myristate‐13‐acetate) augments 2‐chloroadenosine‐elicited accumulation of cyclic AMP in guinea pig cerebral cortical particulate preparations
Authors: Hollingsworth Elizabeth B. , Sears Edward B. , Daly John W.
Published: July 2002

Norepinephrine and histamine markedly augment accumulations of cyclic AMP elicited by 2‐chloroadenosine in a guinea pig cerebral cortical vesicular preparation. In addition, these biogenic amines stimulate phosphatidylinositol turnover. Phosphatidylinositol turnover is associated with mobilization of internal calcium and with stimulation of protein kinase C. Phorbol‐12‐myristate‐13‐acetate (PMA), a known activator of protein kinase C, has no effect on cyclic AMP levels alone, but in a concentration‐dependent manner enhances accumulations of cyclic AMP elicited by 2‐chloroadenosine. PMA, like norepinephrine, also enhances accumulations of cyclic AMP elicited by histamine. PMA has no effect on the synergistic accumulations of cyclic AMP elicited by combinations of amines and 2‐chloroadenosine. PMA also augments accumulations of cyclic AMP elicited by forskolin. The results suggest that activation of, phosphatidylinositol turnover by biogenic amines may lead via stimulation of protein kinase C to enhanced responsiveness of cyclic AMP‐generating systems.
Identification of a major endogenous substrate for phospholipid/Ca2+‐dependent kinase in pancreatic acini as Gc (vitamin D‐binding protein)
Authors: Wooten Marie W. , Nel Andre E. , Goldschmidt-Clermont Pascal J. , Galbraith Robert M. , Wrenn Robert W.
Published: July 2002

A major 56 kDa substrate for phospholipid/Ca2+‐dependent kinase (C‐kinase) in pancreatic acinar cells is physicochemically and immunologically indistinguishable from the vitamin D‐binding protein, Gc or group‐specific component. Cellular Gc was also phosphorylated in intact cells following treatment with carbachol as a physiological stimulus. These findings indicate the potential usefulness of Gc as a defined substrate for further studies of the biological role of C‐kinase activity in pancreatic acini and possibly in other cells.
Electrophysiological responses to bradykinin and microinjected inositol polyphosphates in neuroblastoma cells
Authors: Tertoolen Leon G.J. , Tilly Ben C. , Irvine Robin F. , Moolenaar Wouter H.
Published: July 2002

Addition of bradykinin to mouse N1E‐115 neuroblastoma cells evokes a rapid but transient rise in cytoplasmic free Ca2+ concentration ([Ca2+]i). The [Ca2+]i rise is accompanied by a transient membrane hyperpolarization, due to a several‐fold increase in K+ conductance, followed by a prolonged depolarizing phase. Pre‐treatment of the cells with a Ca2+‐ionophore abolishes the hormone‐induced hyperpolarization but leaves the depolarizing phase intact. The transient hyperpolarization can be mimicked by iontophoretic injection of IP3(1,4,5) or Ca2+, but not by injection of IP3(1,3,4), IP4(1,3,4,5) or Mg2+ into the cells. Instead, IP3(1,3,4) evokes a small but significant membrane depolarization in about 50% of the cells tested. Microinjected IP4(1,3,4,5) has no detectable effect, nor has treatment of the cells with phorbol esters. These results suggest that, while IP3(1,4,5) triggers the release of stored Ca2+ to hyperpolarize the membrane, IP3(1,3,4) may initiate a membrane depolarization.
Disruption of the Lys‐290‐Glu‐342 salt bridge in human α1‐antitrypsin does not prevent its synthesis and secretion
Authors: Foreman R.C.
Published: July 2002

The object of this work was to test the hypothesis that failure to secrete the Z variant of human α1‐antitrypsin is related to the loss of a particular structural feature, the Lys‐290 to Glu‐342 salt bridge. Oligonucleotide‐directed mutagenesis was used to disrupt the salt bridge by substituting a glutamic acid for lysine at residue 290. RNA transcripts prepared from this mutant DNA and from the normal cDNA were both able to direct the synthesis of protein in a cell‐free system and after injection into Xenopus oocytes. Furthermore, the constructed mutant α‐antitrypsin was secreted as readily as the normal inhibitor.
Circular dichroism and fluorescence of polyethylene glycol‐subtilisin in organic solvents
Authors: Pasta P. , Riva S. , Carrea G.
Published: July 2002

Subtilisin Carlsberg has been made soluble in organic solvents such as dioxane and acetonitrile by covalent linking to polyethylene glycol. Far‐ultraviolet circular dichroism and intrinsic protein fluorescence have shown that subtilisin dissolved in dioxane, in which the enzyme is active and highly stable, maintains the native secondary structure as well as the native microenvironment for tyrosyl residues. In acetonitrile subtilisin undergoes conformational changes that cause enzyme inactivation and precipitation.
Synergism in cytosolic Ca2+ mobilization between bradykinin and agonists for pertussis toxin‐sensitive G‐protein‐coupled receptors in NG 108‐15 cells
Authors: Okajima Fumikazu , Kondo Yoichi
Published: July 2002

Bradykinin (BK) induced a transient and pertussis toxin (PT)‐insensitive increase in cytosolic Ca2+ ([Ca2+]i) in NG 108‐15 neuroblastoma × glioma hybrid cells, whereas leucine‐enkephalin (EK), somatostatin, norepinephrine or carbachol showed a weak but PT‐sensitive action. When any one of the latter agonists was applied to the cells treated with low doses of BK, however, the level of [Ca2+]i rise caused by the agonist was remarkably increased in a PT‐sensitive manner. The decreasing of extracellular Ca2+ only slightly influenced the actions or these agonists. Thus, synergism between a BK receptor and PT‐sensitive G‐protein‐coupled receptors results in marked intracellular Ca2+ mobilization by the latter agonists.
Modification of the amino acid specificity of tyrosyl‐tRNA synthetase by protein engineering
Authors: de Prat Gay Gonzalo , Duckworth Harry W. , Fersht Alan R.
Published: July 2002

The amino acid specificity of Bacillus stearothermophilus tyrosyl‐tRNA synthetase was studied by site‐directed mutagenesis of residues close to the active site. X‐ray crystallographic studies of the enzyme have suggested that Asp‐176 is a major determinant of amino acid specificity, as its carboxylate is observed to make a hydrogen bond with the hydroxyl group of the substrate tyrosine. Previous efforts to test the importance of Asp‐176 by site‐directed mutagenesis led to inactive enzymes. We have now investigated the catalytic properties of enzymes altered, not at Asp‐176 itself, but instead at two amino acids, Asn‐123 and Trp‐126, that appear in the crystallographic structure to form hydrogen bonds with Asp‐176. Mutation of Trp‐126 does not affect the kinetics of activation with respect to ATP but leads to modest increases in the K
m for tyrosine. Conversely, position Asn‐123 mutants are strongly affected: 160‐fold lower k
cat and 5‐fold higher K
m for the Ala‐123; and 17‐fold decrease and 270‐fold increase, respectively, of the same parameters for the Asp‐123 mutation. The specificity against phenylalanine was determined from the ratios of k
cat/K
m for the amino acids in the pyrophosphate exchange reaction. The ratio of 1.2 × 105 for the wild‐type enzyme decreases 4‐fold on mutation of Asn‐123 but increases 7‐fold on the mutation of Trp‐126→Phe and 2‐fold on Trp‐126→Leu. The wild‐type enzyme has not reached the maximum limit of discrimination between tyrosine and phenylalanine.
Primary structure of three cationic peptides from porcine neutrophils
Authors: Mirgorodskaya Olga A. , Shevchenko Andrew A. , Abdalla Kamal Omer M.A. , Chernushevich Igor V. , Egorov Tsezi A. , Musoliamov Alexander X. , Kokryakov Vladimir N. , Shamova Olga V.
Published: July 2002

The primary structure of three major cationic peptides from porcine neutrophils has been determined. The sequencing was made by the combined use of electrospray ionization mass spectrometry and Edman degradation. The determined sequences unambiguously show that these peptides can not be considered as defensins.
SNAP‐25 is present in a SNARE complex in adrenal chromaffin cells
Authors: Roth Dagmar , Burgoyne Robert D.
Published: July 2002

SNAP‐25 (synaptosomal‐associated protein 25 kDa) is a target for botulinum neurotoxins A and E, which both inhibit neurotransmitter release, and was recently identified together with syntaxin and synaptobrevin as receptors for NSF and α‐SNAP. We show that SNAP‐25 was enriched in the microsomal fraction from adrenal medulla, although the level of SNAP‐25 in adrenal medullary microsomes was about 20‐fold less than in brain microsomes. Immunocytochemistry confirmed the presence of SNAP‐25 in cultured chromaffin cells and showed plasma membrane staining. Using immunoprecipitation, we found that SNAP‐25 was present in a complex with syntaxin, synaptobrevin, synaptotagmin, NSF, α‐SNAP and other unidentified polypeptides. These data indicate that SNAP‐25 in chromaffin cells is present in a complex similar to that identified in brain.
Modelling flavin and substrate substituent effects on the activation barrier and rate of oxygen transfer by p‐hydroxybenzoate hydroxylase
Authors: Ridder Lars , Palfey Bruce A. , Vervoort Jacques , Rietjens Ivonne M.C.M.
Published: July 2002

The simulation of enzymatic reactions, using computer models, is becoming a powerful tool in the most fundamental challenge in biochemistry: to relate the catalytic activity of enzymes to their structure. In the present study, various computed parameters were correlated with the natural logarithm of experimental rate constants for the hydroxylation of various substrate derivatives catalysed by wild‐type para‐hydroxybenzoate hydroxylase (PHBH) as well as for the hydroxylation of the native substrate (p‐hydroxybenzoate) by PHBH reconstituted with a series of 8‐substituted flavins. The following relative parameters have been calculated and tested: (a) energy barriers from combined quantum mechanical/molecular mechanical (QM/MM) (AM1/CHARMM) reaction pathway calculations, (b) gas‐phase reaction enthalpies (AM1) and (c) differences between the HOMO and LUMO energies of the isolated substrate and cofactor molecules (AM1 and B3LYP/6‐31+G(d)). The gas‐phase approaches yielded good correlations, as long as similarly charged species are involved. The QM/MM approach resulted in a good correlation, even including differently charged species. This indicates that the QM/MM model accounts quite well for the solvation effects of the active site surroundings, which vary for differently charged species. The correlations obtained demonstrate quantitative structure activity relationships for an enzyme‐catalysed reaction including, for the first time, substitutions on both substrate and cofactor.
Interdomain interactions in oligomeric enzymes: creation of asymmetry in homo‐oligomers and role in metabolite channeling between active centers of hetero‐oligomers
Authors: Nagradova Natalya K
Published: July 2002

Interdomain interactions play an important role in the structural organization of many enzymes and the conformational flexibility of their molecules. In this review, the role of intrasubunit and intersubunit domain–domain interactions in the origins of pre‐existent asymmetry of homo‐oligomeric D‐glyceraldehyde‐3‐phosphate dehydrogenase and tryptophanyl‐tRNA synthetase is discussed on the basis of recent X‐ray data and other available information about the properties of these and related enzymes. In addition, a novel key function of interdomain interactions is considered: their potential contribution to intramolecular channeling of intermediates between active centers located on different subunits of a hetero‐oligomeric enzyme (α,β‐heterodimeric carbamoyl phosphate synthetase).
Tailoring Multiple Porosities of Hierarchical ZSM‐5 Zeolites by Carbon Dots for High‐Performance Catalytic Transformation
Authors: Zhao Shufang , Kim Kyung Duk , Wang Lizhuo , Ryoo Ryong , Huang Jun
Published: November 2020

A simple and high‐efficiency method is proposed to synthesize hierarchical ZSM‐5 zeolites with micropore and multistage mesopores by adopting water‐soluble carbon dots (CDots) with various size distributions, such as 1‐stage size distribution of CDots‐1 of around 23 nm, 2‐stage size distribution of CDots‐2 of 6 and 9 nm, 3‐stage size distribution of CDots‐3 of 5, 8, and 18 nm. The abundant OH and COOH groups on the surface of CDots provide high solubility in water. The characterization techniques confirmed that the dual‐porous h‐ZSM‐5 (MIcro–mEsopores) and multi‐porous h‐ZSM‐5 (MIcro–mEso–mEsopores), h‐ZSM‐5 (MIcro–mEso–mEso–mEsopores, M‐IEEE) catalysts are obtained. Notably, the hierarchical ZSM‐5(M‐IEEE) catalyst with micropore of 0.55 nm, two small mesopores of 4.8 and 7.4 nm, and one large mesopore of 17.5 nm show excellent catalytic performance with the highest 1,3,5‐triisopropylbenzene (TIPB) cracking conversion (97.3%) and high stability. Similarly, the h‐ZSM‐5(M‐IEEE) shows the high ethanol to olefins conversion (100%). The improved catalytic activity can be attributed to the more efficient diffusion of reactants and products in the crystals with the help of multistage mesopores, improved anti‐coking stability, combined with the effect of suitable acidity, and the increased accessibility of the acid sites.
Site‐Selective Pd‐Catalysed Fujiwara‐Moritani type Reaction of N,S‐Heterocyclic Systems with Olefins
Authors: Danton Fanny , Najjar Riham , Othman Mohamed , Lawson Ata Martin , Moncol Ján , Ghinet Alina , Rigo Benoît , Oulyadi Hassan , Daïch Adam
Published: November 2020

Dihydro‐1,4‐thiazine skeletons bearing olefin fragment at their α‐position were prepared through a Pd(OAc)2‐catalysed Fujiwara‐Moritani type reaction via C−H alkenylation with olefins. This approach is selective, generalizable to a wide range of olefins and requires only 1 eq. of Ag2CO3 without the need of co‐oxidant. The C−H bond activation proved to be strongly dependent on the olefin's substitution while unfused dihydro‐1,4‐thiazines seemed to be affected by the oxidation state of the sulfur atom. The utility of olefins obtained was demonstrated by their implication in the dipolar cycloaddition reaction with a non‐stabilized azomethine ylide.

magnified image
A Stable Triplet‐Ground‐State Conjugated Diradical Based on a Diindenopyrazine Skeleton
Authors: Wang Zi‐Yuan , Dai Ya‐Zhong , Ding Li , Dong Bo‐Wei , Jiang Shang‐Da , Wang Jie‐Yu , Pei Jian
Published: November 2020

High‐spin conjugated radicals have great potential in magnetic materials and organic spintronics. However, to obtain high‐spin conjugated radicals is still quite challenging due to their poor stability. We report the successful synthesis and isolation of a stable triplet conjugated diradical, 10,12‐diaryldiindeno[1,2‐b:2′,1′‐e]pyrazine (m‐DIP). With the m‐xylylene analogue skeleton containing electron‐deficient sp2‐nitrogen atoms, m‐DIP displays significant aromatic character within its pyrazine ring and its spin density mainly delocalizes on the meta‐pyrazine unit, making it a triplet ground state conjugated diradical. Our work provides an effective “spin density tuning” strategy for stable high‐spin conjugated radicals.
Manganese‐Catalyzed Asymmetric Hydrogenation of Quinolines Enabled by π–π Interaction**
Authors: Liu Chenguang , Wang Mingyang , Liu Shihan , Wang Yujie , Peng Yong , Lan Yu , Liu Qiang
Published: November 2020

The non‐noble metal‐catalyzed asymmetric hydrogenation of N‐heteroaromatics, quinolines, is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the asymmetric hydrogenation of quinolines, affording high yields and enantioselectivities (up to 97 % ee). A turnover number of 3840 was reached at a low catalyst loading (S/C=4000), which is competitive with the activity of most effective noble metal catalysts for this reaction. The precise regulation of the enantioselectivity were ensured by a π–π interaction.
Palladium‐Catalyzed Site‐Selective [3+2] Annulation via Benzylic and meta C−H Bond Activation
Authors: He Qiyuan , Chatani Naoto
Published: November 2020

The palladium‐catalyzed [3+2] annulation of aromatic amides with maleimides via the activation of ortho benzylic C−H and meta C−H bonds is reported. Carboxamide and anilide type substrates that contain a 2‐methylthiophenyl group both participate in this [3+2] annulation, indicating that the presence of a 2‐methylthiophenyl directing group is a key for the success of the reaction. The first C−H bond activation at the benzylic C−H bond is followed by a second C−H bond activation at the meta C−H bond to give five‐membered cyclic products. The cleavage of these C−H bonds is irreversible.
Revealing the marked differences of phosphorescence efficiencies on C˄N˄N‐coordinated Pt(II) complexes: A theoretical study
Authors: Ren Xue‐Feng , Liu Xia , Kang Guo‐Jun , Li Ke
Published: November 2020

In this study, green phosphorescent Pt(II) complexes with N,N‐diphenyl‐6‐(1H‐pyrazol‐1‐yl)pyridin‐2‐amine (Ndpp) coordinated ligands, [Pt (Ndpp)Cl] 2a, [Pt (Ndpp)Pb, Pb = (prop‐1‐ynyl)benzene] 2b, and [Pt (Ndpp)CN] 2aCN were theoretically investigated by means of density functional theory and time‐dependent density functional theory calculations to reveal their marked distinct phosphorescence quantum yields. These complexes exhibit evident absorption bands in the 200–450 nm region but emit strong green light with marked differences of phosphorescence quantum yields. Compared with the complex 2a, the complex 2b possesses large oscillator strengths of absorption spectra, strong spin‐orbit coupling, and transition electric dipole moment, as well as small singlet‐triplet splitting energies, which conduces to enhancing its radiative decay. To illustrate the nonradiative decay process, the transition state (TS) between the triplet metal‐centered (3MC) state and the excited state (T1) was optimized. The 3MC state is found to be the minimum energy crossing point (MECP) between the T1 state and the S0 state. Compared with the complex 2a, the complex 2b possesses a much larger energy barrier to the MECP state from the T1 state, so it is strongly emissive in the green region. Besides, the introduction of CN substitutions on 2a is useful for enhancing the energy barrier to the thermal deactivation pathway of 3MLCT → TS → MECP. These results demonstrate that the modification of metal–ligand conjugation is an effective way to develop high‐performance phosphorescent materials.
The nonisothermal two‐phase model based on mixed convection in passive μDMFC
Authors: Wang Luwen , Yuan Zhenyu
Published: November 2020

During the working process of passive microdirect methanol fuel cell (μDMFC), the characteristics of inverse movement between two‐phase substances are quite distinct from macro gas–liquid inverse movement, including electrochemical reactions, electrical drag, multicomponent diffusion, evaporation, and condensation. Due to the complexity of internal operation system of μDMFC, it is difficult to monitor and analyze dynamic property currently only by experiment. Therefore, in this paper, an integrated and accurate prediction model to explore two‐phase transmission is build up, to investigate different effects by varying parameters, and to maximize cell performance. First, the accuracy of the simulation is proved by experimental tests. Then, a comprehensive, two‐phase mass transfer model of passive DMFC is established. The methanol concentration, oxygen concentration, cathode and anode flow velocity and pressure distribution, potential distribution, and anode saturation distribution are studied. Moreover, a nonisothermal model considering the natural convection in the anode is established, the velocity field in the tank, the temperature distribution of the cell, the methanol distribution, and the temperature distribution on the anode catalyst layer is optimized. The research results can provide accurate theoretical support for fuel cell internal component preparation and μDMFC portable applications.
A High‐Efficiency Hematite Photoanode with Enhanced Bonding Energy Around Fe Atoms
Authors: Lan Yangchun , Kang Shuai , Cui Dehu , Hu Zhuofeng
Published: November 2020

Hematite nanoarrays are important photoanode materials. However, they suffer from serious problems of charge transfer and surface states; in particular, the surface states hinder the increase in photocurrent. A previous strategy to suppress the surface state is the deposition of an Fe‐free metal oxide overlayer. Herein, from the viewpoint of atomic bonding energy, it is found that the strength of bonding around Fe atoms in the hematite is the key to suppressing the surface states. By treating the surface of hematite with Se and NaBH4, the Fe2O3 transforms to a double‐layer nanostructure. In the outer layer, the Fe−O bonding is reinforced and the Fe−Se bonding is even stronger. Therefore, the surface states are inhibited and the increase in the photocurrent density becomes much faster. Besides, the treatment constructs a nanoscale p–n junction to promote the charge transfer. Improvements are achieved in onset potential (0.25 V shift) and in photocurrent density (5.8 times). This work pinpoints the key to suppressing the surface states and preparing a high‐efficiency hematite nanoarray, and deepens our understanding of hematite photoanodes.
Circularly Polarized Luminescence of a Stereogenic Curved Paraphenylene Anchoring a Chiral Binaphthyl in Solution and Solid State
Authors: Sato Kenta , Hasegawa Masashi , Nojima Yuki , Hara Nobuyuki , Nishiuchi Tomohiko , Imai Yoshitane , Mazaki Yasuhiro
Published: November 2020

Invited for the cover of this issue are Masashi Hasegawa, Yoshitane Imai, Yasuhiro Mazaki and co‐workers at Kitasato University, Kindai University and Osaka University. The image depicts a stereogenic twisted cycloparaphenylene that exhibits circularly polarized luminescence in a polymethyl methacrylate thin film. Read the full text of the article at 10.1002/chem.202004283.
DFT and IsoStar Analyses to Assess the Utility of σ‐ and π‐Hole Interactions for Crystal Engineering
Authors: Mooibroek Tiddo Jonathan
Published: November 2020

The interpretation of 36 charge neutral ‘contact pairs’ from the IsoStar database was supported by DFT calculations of model molecules 1–12, and bimolecular adducts thereof. The ‘central groups’ are σ‐hole donors (H2O and aromatic C−I), π‐hole donors (R−C(O)Me, R−NO2 and R−C6F5) and for comparison R−C6H5 (R=any group or atom). The ‘contact groups’ are hydrogen bond donors X−H (X=N, O, S, or R2C, or R3C) and lone‐pair containing fragments (R3C−F, R−C≡N and R2C=O). Nearly all the IsoStar distributions follow expectations based on the electrostatic potential of the ‘central‐’ and ‘contact group’. Interaction energies (ΔEBSSE) are dominated by electrostatics (particularly between two polarized molecules) or dispersion (especially in case of large contact area). Orbital interactions never dominate, but could be significant (∼30 %) and of the n/π→σ*/π* kind. The largest degree of directionality in the IsoStar plots was typically observed for adducts more stable than ΔEBSSE≈−4 kcal⋅mol−1, which can be seen as a benchmark‐value for the utility of an interaction in crystal engineering. This benchmark could be met with all the σ‐ and π‐hole donors studied.
Petrogenesis of ca. 113 Ma volcanic rocks in the central Lhasa subterrane, southern Tibet: Implications for the tectonic setting and continental crustal reworking
Authors: Huang Yu , Zhao Zhidan , Jiao Jiangang , Qiu Bibo , Ma Zhen , Zhu Di‐Cheng
Published: November 2020

Voluminous Early Cretaceous volcanic rocks in the central Lhasa subterrane provide an ideal opportunity for understanding the mantle–crust interaction and tectonic‐magmatic evolution of the Lhasa Terrane. Here, we report zircon U–Pb ages, geochemical and Sr–Nd–Pb–Hf isotopic data for the Early Cretaceous volcanic rocks, including high‐silica rhyolites (117.2 ± 1.1 Ma) and contemporaneous andesites (114.1 ± 0.8 Ma) in the Sailipu area, central Lhasa subterrane. All these rocks show enriched light rare earth elements (LREE), and radioactive heat‐generating elements (e.g., Th, U, K, and Pb) but depleted high‐field‐strength elements (HFSEs, e.g., Nb, Ta, P, and Ti). The different bulk‐rock Sr–Nd–Pb and zircon Hf isotopic compositions of the rhyolites and andesites suggest that these rocks have distinct magma sources and petrogenetic history rather than an identical source involving assimilation‐fractional crystallization process. The Sailipu high‐silica rhyolites exhibit the characteristics of fractional crystallization and have varying zircon εHf(t) values (−12.2 to +5.2), negative εNd(t) values (−9.5 to −1.6), high and variable initial Sr isotopic compositions ([87Sr/86Sr]i = 0.7047–0.7116) and radiogenic Pb isotopic signatures (206Pb/204Pb = 18.784–18.802, 207Pb/204Pb = 15.722–15.737, and 208Pb/204Pb = 39.382–39.492). A combined process of magma mixing (involving crustal‐derived felsic melts and mantle‐derived mafic melts) and subsequent fractional crystallization were mainly responsible for the formation of these high‐silica rhyolites. The Sailipu andesites show more enriched Sr–Nd isotopic compositions [(87Sr/86Sr)i = 0.7088–0.7154, εNd(t) = −9.9 to −6.7] relative to rhyolites, and less radiogenic Pb isotopic compositions (206Pb/204Pb = 18.632–18.669, 207Pb/204Pb = 15.686–15.689, 208Pb/204Pb = 39.140–39.201). They were likely derived from partial melting of an enriched mantle wedge previously metasomatized by melts derived from subducted sediments. We interprete these Early Cretaceous volcanic rocks as the product of slab break‐off during the southward subduction of the Bangong‐Nujiang Tethyan oceanic seafloor. The dominantly positive εHf(t) and ancient TDMC ages (0.85–1.90 Ga) of Sailipu high‐silica rhyolites further imply that, under the stress relaxation regime, the mantle‐derived melts locally reworked the ancient basement of the central Lhasa subterrane.
Effects of bedrock groundwater discharge on spatial variability of dissolved carbon, nitrogen, and phosphorous concentrations in stream water within a forest headwater catchment
Authors: Egusa Tomohiro , Kumagai Tomo'omi , Oda Tomoki , Ohte Nobuhito
Published: November 2020

The quantitative evaluation of the effects of bedrock groundwater discharge on spatial variability of stream dissolved organic carbon (DOC), dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorous (DIP) concentrations has still been insufficient. We examined the relationships between stream DOC, DIN and DIP concentrations and bedrock groundwater contribution to stream water in forest headwater catchments in warm‐humid climate zones. We sampled stream water and bedrock springs at multiple points in September and December 2013 in a 5 km2 forest headwater catchment in Japan and sampled groundwater in soil layer in small hillslopes. We assumed that stream water consisted of four end members, groundwater in soil layer and three types of bedrock groundwater, and calculated the contributions of each end member to stream water from mineral‐derived solute concentrations. DOC, DIN and DIP concentrations in stream water were compared with the calculated bedrock groundwater contribution. The bedrock groundwater contribution had significant negative linear correlation with stream DOC concentration, no significant correlation with stream DIN concentration, and significant positive linear correlation with stream DIP concentration. These results highlighted the importance of bedrock groundwater discharge in establishing stream DOC and DIP concentrations. In addition, stream DOC and DIP concentrations were higher and lower, respectively, than those expected from end member mixing of groundwater in soil layer and bedrock springs. Spatial heterogeneity of DOC and DIP concentrations in groundwater and/or in‐stream DOC production and DIP uptake were the probable reasons for these discrepancies. Our results indicate that the relationships between spatial variability of stream DOC, DIN and DIP concentrations and bedrock groundwater contribution are useful for comparing the processes that affect stream DOC, DIN and DIP concentrations among catchments beyond the spatial heterogeneity of hydrological and biogeochemical processes within a catchment.
Numerical and experimental investigations on aggradation and degradation in irrigation canals accounting for infiltration*
Authors: Rohilla Kapil , Kumar Sanjay , Kumar Pardeep
Published: November 2020

A numerical model was used in the present study to predict aggradation, degradation, and subsurface moisture content in irrigation canals. The numerical model solved Saint‐Venant and sediment continuity equations to analyse overland flow and sediment transport, whereas Richard's equation was used to analyse subsurface movement of water. Saint‐Venant and sediment continuity equations were solved by using the MacCormack scheme based on the finite difference method, and the Richard's equation was solved by using a mass‐conservative fully implicit finite difference method. Extensive irrigation canal experiments involving measurement of aggradation, degradation, and subsurface moisture content were conducted to assess the performance of the numerical model. The predicted aggradation and degradation represented a good agreement with data recorded in laboratory. Soil moisture profiles were estimated for sediment‐laden water and clear water conditions in irrigation canals. But the effect of sediment‐laden water on the moisture profiles was observed as insignificant. The observed and the model‐predicted soil moisture varied marginally as the observed moisture was attributed to errors during the collection of soil samples from the experimental field.
MicroRNA‐223 triggers inflammation in porcine aorta by activating NLRP3 inflammasome under selenium deficiency
Authors: Qing Zhang , Kaixin Zhang , Yanfei Han , Yiming Zhang , Hua Xue , Ling Zhou , Guangliang Shi , Shu Li
Published: November 2020

Selenium (Se) is an essential trace element in organism. Se deficiency can cause many diseases, including vascular disease. Studies have shown that inflammation is the main inducement of vascular disease, microRNA (miRNA) can influence inflammation in various ways, and Se deficiency can affect miRNAs expression. To study the mechanism of aorta damage caused by Se deficiency, we constructed a Se deficiency porcine aorta model and found that Se deficiency can significantly inhibit miR‐223, which downregulates the expression of nucleotide‐binding oligomerization domain‐like receptor family 3 (NLRP3). Subsequently, we found that in Se deficiency group, NLRP3, and its downstream (caspase‐1, apoptosis‐related spot‐like protein [ASC], IL‐18, IL‐1β) expression was significantly increased. In vitro, we cultured pig iliac endothelium cell lines, and constructed miR‐223 knockdown and overexpression models. NLRP3 messenger RNA and protein levels were significant increased in the knockdown group, and decreased in the overexpression group. The results of this study show that Se deficiency in porcine arteries can induce inflammation through miR‐223/NLRP3.
Evaluation of enamel loss by scanning electron microscopy after debonding brackets place with four different adhesives
Authors: Rodríguez‐Chávez Jacqueline Adelina , Arenas‐Alatorre Jesús Ángel , Flores‐Ruiz Hugo M. , Flores‐Ledesma Abigailt , Aguilar‐Pérez Fernando Javier
Published: November 2020

The clinically adequate shear bond strengths (SBS) should be from 2.8 to 10 MPa. The aim of this research is to observe tooth enamel loss through a scanning electron microscope (SEM) during the debonding of braces of four adhesive systems. Then, 100 premolars were used in 4 groups of 25 specimens each, for Transbond MIP (G1), Enlight (G2), Stylus (G3), and Transbond Plus SEP (G4). The research was done under the NOM ISO/TS 11405:2015. Gemini 3M were placed under the manufacturer's recommendations. The SBS test was done at 24 hr in an Instron electromechanical universal testing machine at 1 mm/1 min. Adhesive remnant index (ARI) was measured, all of the brackets where examined in the SEM. For the shear bonding strength G1 = 10.09 ± 2.73 MPa, G2 = 9.27 ± 3.99 MPa, G3 = 7.83 ± 4.46 MPa, and G4 = 6.40 ± 2.85 MPa statistically significant differences were found when comparing the four groups (p = .002). In the Tukey post hoc test, G1 versus G4 and G2 versus G4, statistically significant differences were found. For the ARI a value of 1 in 46%, followed by a value of 2 in 38%, a value of 3 in 13% and a value of 0 in 3% of the total samples, finding statistically significant differences (p < .001). In relation to the tooth enamel loss due to SBS, statistically significant differences were found (p = .326). G1 and G4 had not statistically significant differences. Even though our results concur with the appropriate clinical values, we observed tooth enamel loss with Transbond Plus SEP and Stylus.
Element‐free Galerkin numerical mode‐matching method for static and time‐harmonic electromagnetic fields in orthogonal‐plano‐cylindrically layered media
Authors: Dun Yueqin , Zeng Shubin , Chen Jiefu
Published: November 2020

This paper combines the numerical mode‐matching (NMM) method with the element‐free Galerkin (EFG) method for the efficient modeling of electromagnetic waves in cylindrically layered media with multiple horizontal beds. In the implementation of the conventional NMM scheme, finite element method (FEM) is commonly used to discretize the radial direction. To improve the efficiency for the discretization along the radial direction, EFG method is utilized instead to construct the element‐free Galerkin NMM (EFG‐NMM) scheme. As a meshless method, EFG scheme avoids the complexity of mesh generation as well as improves the numerical accuracy compared to FEM. The EFG‐NMM scheme is developed for both static and time‐harmonic electromagnetic waves. Excellent agreement between EFG‐NMM and FEM‐NMM is verified by simulating different numerical examples.
Hydrogel‐Forming Microneedles: Current Advancements and Future Trends
Authors: Turner Joseph G. , White Leah R. , Estrela Pedro , Leese Hannah S.
Published: November 2020

In this focused progress review, the recent developments and trends of hydrogel‐forming microneedles (HFMs) and potential future directions are presented. Previously, microneedles (solid, hollow, coated, and dissolving microneedles) have primarily been used to enhance the effectiveness of transdermal drug delivery to facilitate a wide range of applications such as vaccinations and antibiotic delivery. However, the recent trend in microneedle development has resulted in microneedles formed from hydrogels which have the ability to offer transdermal drug delivery and, due to the hydrogel swelling nature, passively extract interstitial fluid from the skin, meaning they have the potential to be used for biocompatible minimally invasive monitoring devices. Thus, in this review, these recent trends are highlighted, which consolidate microneedle design considerations, hydrogel formulations, fabrication processes, applications of HFMs and the potential future opportunities for utilizing HFMs for personalized healthcare monitoring and treatment.
Mathematical modeling for novel coronavirus (COVID‐19) and control
Authors: Alqarni Marei Saeed , Alghamdi Metib , Muhammad Taseer , Alshomrani Ali Saleh , Khan Muhammad Altaf
Published: November 2020

In the present investigations, we construct a new mathematical for the transmission dynamics of corona virus (COVID‐19) using the cases reported in Kingdom of Saudi Arabia for March 02 till July 31, 2020. We investigate the parameters values of the model using the least square curve fitting and the basic reproduction number is suggested for the given data is ℛ0 ≈ 1.2937. The stability results of the model are shown when the basic reproduction number is ℛ0 < 1. The model is locally asymptotically stable when ℛ0 < 1. Further, we show some important parameters that are more sensitive to the basic reproduction number ℛ0 using the PRCC method. The sensitive parameters that act as a control parameters that can reduce and control the infection in the population are shown graphically. The suggested control parameters can reduce dramatically the infection in the Kingdom of Saudi Arabia if the proper attention is paid to the suggested controls.
Development of a superhydrophilic nanofiber membrane for oil/water emulsion separation via modification of polyacrylonitrile/polyaniline composite
Authors: Shakiba Mohamadreza , Nabavi Seyed Reza , Emadi Hamid , Faraji Mehdi
Published: November 2020

In this research, polyaniline (PANI) was used to modify polyacrylonitrile (PAN) electrospun nanofibers for separating oil/water (O/W) emulsions due to its hydrophilic amino groups and simple synthesis. The fabrication of PAN/PANI membranes was carried out by two different methods: blending of PANI with PAN in pre‐electrospinning solution and coating of PANI on the PAN electrospun nanofibers using in situ polymerization of aniline. The effect of PANI composition (10, 20, 30 and 40 wt% with respect to the weight of PAN) and electrospinning temperature (25°C, 40°C and 55°C) was investigated in PAN/PANI membrane fabrication. The prepared membranes were characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), water and under water oil contact angle (WCA and UOCA) measurement and mechanical tensile test. Regarding the results, PAN/40%PANI nanofibers prepared at 40°C was considered as the superhydrophilic nanofibers (WCA < 5°) and the most suitable membrane among the samples for separation of O/W emulsions. Separation studies revealed a flux of 1300 Lmh (pure water) under gravity and an efficient oil rejection of about 98.8% for PAN/40%PANI@40°C membrane. Hence, the PAN/40%PANI@40°C membrane was subjected to additional tests including separation of different industrial oils, emulsion separation with surfactant agent, separation under harsh acidic/basic conditions and fouling test. The results confirmed an efficient performance of the obtained superhydrophilic membrane for O/W separation, which make it a potential candidate for the purification of water from industrial organic pollutant.