bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, structural, spectroscopic, and thermal studies of some transition‐metal complexes of a ligand containing the amino mercapto triazole moiety
Authors: Emam Sanaa M. , Tolan Dina A. , El‐Nahas Ahmed M.
Published: February 2020

A new series of transition‐metal complexes of Schiff base ligand containing the amino mercapto triazole moiety (HL) was prepared. The Schiff base and its metal complexes were elucidated by different spectroscopic techniques (infrared [IR], 1H nuclear magnetic resonance, UV–Visible, mass, and electron spin resonance [ESR]), and magnetic moment and thermal studies. Quantum chemical calculations have been carried out to study the structure of the ligand and some of its complexes. The IR spectra showed that the ligand is chelated with the metal ion in a neutral, tridentate, and bidentate manner using NOS and NO donors in complexes 1–6, 10–12, and 7 and 8, respectively, whereas it behaves in a monobasic tridentate fashion using NOS donor sites in copper(II) nitrate complex (9). The magnetic moment and electronic spectra data revealed octahedral and square pyramidal geometries for complexes 2, 11, 12, and 5–8 and 10, respectively. However, the other complexes were found to have tetrahedral (4), trigonal bipyramidal (1 and 3), and square planar (9) structures. Thermal studies revealed that the chelates with different crystallized solvents undergo different types of interactions and the decomposition pathway ended with the formation of metal oxygen (MO) and metal sulfur (MS) as final products. The ESR spectrum of copper(II) complex 10 is axial in nature with hyperfine splitting with 2B1g as a ground state. By contrast, complexes 7 and 8 undergo distortion around the Cu(II) center, affording rhombic ESR spectra. The HL ligand and some of its complexes were screened against two bacterial species. Data showed that complex 12 demonstrated a better antibacterial activity than HL ligand and other chelates.
Adaptive neuronal induction motor control with an 84‐pulse voltage source converter
Authors: Beltran‐Carbajal Francisco , Tapia‐Olvera Ruben , Valderrabano‐Gonzalez Antonio , Lopez‐Garcia Irvin
Published: February 2020

This paper deals with the problem of harmonic distortion in velocity control drives for large horsepower three‐phase induction motors. A new solution alternative to considerably reduce harmonic distortion in controlled large‐capacity induction motors is introduced. An adaptive neural velocity reference trajectory tracking control scheme based on an 84‐pulse voltage source converter for large horsepower three‐phase induction motors is proposed. Desired flux modulus control is simultaneously performed. Adaptive controller parameters are adjustable online using B‐spline artificial neural networks. Variable load torque of the handled mechanical dynamic system is assumed to be uncertain. Real‐time estimations or measurements of dynamic load torque are unnecessary. Bézier curves are used for desired smooth motion planning to take a large induction motor from its starting towards an operating velocity. Moreover, motion planning is exploited for evasion of harmful mechanical oscillations as well as large peak values of voltages and currents. Closed‐loop efficient velocity profile tracking is confirmed on a 500‐hp induction motor. Comparisons with 6‐pulse and 12‐pulse conventional voltage source converters are also included to highlight the superior energy efficiency of the proposed 84‐pulse ac motor drive. A very low total harmonic distortion of the multiple‐pulse reconstructed three‐phase control voltage signals is also proved. Analytical and numerical results prove the effectiveness and efficiency of the introduced 84‐pulse adaptive neuronal dynamic tracking control strategy.
Tolerance intervals for autoregressive models, with an application to hospital waiting lists
Authors: Cheng Kedai , Young Derek S.
Published: February 2020

Long waiting lists are a symbol of inefficiencies of hospital services. The dynamics of waiting lists are complex, especially when trying to understand how the lists grow due to the demand of a particular treatment relative to a hospital's capacity. Understanding the uncertainty of forecasting growth/decline of waiting lists could help hospital managers with capacity planning. We address this uncertainty through the use of statistical tolerance intervals, which are intervals that contain a specified proportion of the sampled population at a given confidence level. Tolerance intervals are available for numerous settings, however, the approaches for autoregressive models are far more limited. This article fills that gap and establishes tolerance intervals for general AR(p) models, which may also have a mean or trend component present. A rigorous development of tolerance intervals in this setting is presented. Extensive simulation studies identify that good coverage properties are achieved when the AR process is stationary and the parameters of the AR model are well within the stationarity constraints. Otherwise, a bootstrap‐based correction can be applied to improve the coverage probabilities. Finally, the method is applied to the monthly number of patients on hospital waiting lists in England.
PROTOCOL: Effectiveness of interpersonal psychotherapy in comparison to other psychological and pharmacological interventions for reducing depressive symptoms in women diagnosed with postpartum depression in low and middle‐income countries: A systematic review
Authors: Kang Harmeet Kaur , John Denny , Bisht Bandana , Kaur Manmeet , Alexis Obrey , Worsley Aaron
Published: February 2020

Postpartum Depression (PPD) is highly prevalent among women in low and middle income countries (LMICs). World Heath Organization has recognised interpersonal Psychotherapy (IPT) as the first line treatment for the postpartum depression. The primary aim of this review is to evaluate the effectiveness of IPT alone or in combination with pharmacotherapy or other psychosocial therapies for treating depressive symptoms in women with postpartum depression. The generated evidence from this review will help to inform policies in relation to the treatment of postpartum depression in LMICs.
Sandwich‐Type Polyoxometalate Mediates Cobalt Diselenide for Hydrogen Evolution in Acidic Electrolyte
Authors: Ahmad Waqar , Gao Qiang , Zhang Xiao‐Long , Tan Wen , Zhang Long , Gao Min‐Rui , Yu Shu‐Hong
Published: February 2020

Ease of tunability of the redox properties of polyoxometalates (POMs) has made this class of inorganic molecular oxides most attractive for electrocatalytic applications. However, the design of inexpensive transition‐metal oxides for the hydrogen evolution reaction (HER) is a big challenge owing to their insufficient catalytic efficiency and durability at high proton concentrations. Firm linkage of an electroactive POM on the surface of cobalt diselenide nanobelts (CoSe2−NBs) is expected to overcome the issue of stability due to their strong coordination chemistry. Subsequent synergy due to the redox active nature of stabilized POMs facilitates proton‐coupled electron transfer (PCET), which could improve HER activity at higher proton concentrations. Herein, a nanocomposite of a sandwich‐type POM and CoSe2−NBs shows, as predicted, enhanced HER activity in acid with an overpotential of 187 mV at 10 mA cm−2, as well as marked long‐term electrochemical stability. This work offers a route to introduce POMs into a catalyst system to facilitate PCET for boosted electrocatalysis.
Unravelling the Mystery of Solid Solutions: A Case Study of 89Y Solid‐State NMR Spectroscopy
Authors: Xu Jun , Jiang Shijia , Du Yaping
Published: February 2020

Incorporating heteroatoms in functional materials is an invaluable approach to modulate their properties, assuming a solid solution is formed. However, thorough understanding of key structural information on the resulting solid solution, such as the local environment of cations and vacancies, remains a challenge. Solid‐state NMR (SSNMR) spectroscopy is a powerful structural characterization tool, very sensitive to the local environment. Due to the difficulty in signal acquisition and spectral interpretation, SSNMR spectroscopy is relatively less known to chemists and materials scientists. Herein, we present an introductory review to demonstrate how to use 89Y SS NMR spectroscopy to unravel the mystery of solid solutions. In general, 89Y chemical shift varies with different cation/vacancy arrangements in Y coordination spheres, providing ultrafine structural information in the atomic scale. As a case study and an extreme condition, the approach demonstrated in this review can be extended to other systems.
Tetrahedral Silicon‐Centered Dibenzoylmethanatoboron Difluorides: Synthesis, Crystal Structure, and Photophysical Behavior in Solution and the Solid State
Authors: Kononevich Yuriy N. , Temnikov Maxim N. , Korlyukov Alexander A. , Volodin Alexander D. , Dorovatovskii Pavel V. , Sazhnikov Viacheslav A. , Safonov Andrey A. , Ionov Dmitriy S. , Ivanov Anatoly A. , Surin Nikolay M. , Svidchenko Evgeniya A. , Muzafarov Aziz M.
Published: February 2020

Four tetrahedral silicon‐centered derivatives of dibenzoylmethanatoboron difluoride (DBMBF2) were synthesized and characterized. Their structural and optical features both in solution and the solid state were investigated by using X‐ray crystallography, steady‐state and time‐dependent spectroscopy, and DFT‐based calculations. In dilute solutions, the molar absorption coefficient increases from 40500 to 175200 M−1 cm−1 as the number of DBMBF2 fragments in a molecule increases from one to four, while, in contrast, the nonradiative rate constant of fluorescence decay decreases from 0.49 to 0.34. In the solid state, absorption and emission spectra depend on the degree of crystallinity and microcrystal size. The tris‐DBMBF2 derivative forms fully overlapping dimeric structures that exhibit excimer‐like fluorescence, which is accurately predicted by the quantum‐chemical calculations. The mono‐DBMBF2 derivative exhibits fully reverse mechanofluorochromic behavior.
Identification of exvivo catabolites of peptides with doping potential in equine plasma by HILIC‐HRMS
Authors: Guan Fuyu , Fay Savannah , Li Xiaoqing , You Youwen , Robinson Mary A.
Published: February 2020

Bioactive peptides pose a great threat to sports integrity. The detection of these peptides is essential for enforcing their prohibition in sports. Identifying the catabolites of these peptides that are formed ex vivo in plasma may improve their detection. In the present study, the stability of 27 bioactive peptides with protection at both termini in equine plasma was examined under different incubation conditions, using HILIC coupled to HRMS. Of the 27 peptides, 13 were stable after incubation at 37°C for 72 hr, but the remaining 14 were less stable. Ex vivo catabolites of these 14 peptides were detected using their theoretical masses generated in silico, their appearance was monitored over the time course of incubation, and their identity was verified by their product ion spectra. Catabolites identified for chemotactic peptide, DALDA, dmtDALDA, deltorphins I and II, Hyp6‐dermorphin, Lys7‐dermorphin, and dermorphin analog are novel. A d‐amino acid residue at position 2 or 1 of a peptide or next to its C‐terminus protected the relevant terminal from degradation by exopeptidases, but such a residue at position 3 did not. A pGlu residue or N‐methylation at the N‐terminus of a peptide did not protect its N‐terminal. Ethylamide at the C‐terminus of a peptide provided the C‐terminal protection from attacks by carboxypeptidases. The C‐terminal Lys amide in DALDA, dmtDALDA, and Lys7‐dermorphin was susceptible to cleavage by plasma enzymes, which is the first report, to the authors’ knowledge. The results from the present study provide insights into the stability of peptides in plasma.
Quality of life is not affected by thyroid surgery in nontoxic benign goitre in long‐term surveillance—A prospective observational study
Authors: Tabriz Navid , Uslar Verena N. , Tabriz Inga , Weyhe Dirk
Published: February 2020

Objective

Quality of life (QoL) has so far seldom been taken into account by default in decision‐making for surgical indication in thyroid surgery. Therefore, we compared pre‐ and postoperative QoL of patients using the EuroQoL‐5D (EQ‐5D) questionnaire. The influence of certain socio‐economic factors on QoL as a second end‐point was considered.

Design

Prospective cohort study.

Patients

About 153 patients with euthyroid symptomatic benign goitre after hemi‐ and total thyroidectomy (follow‐up 83.6%) have been included.

Measurements

The EQ‐5D questionnaire was used prior to and 1 year after surgery. In addition, a questionnaire for assessment of socio‐economic status was collected.

Results

For n = 90 (n = 67 female, n = 23 male), total thyroidectomy (TT) and, for n = 63 (n = 45 female, n = 18 male), hemithyroidectomy (HT) were performed. None permanent dysfunction of the vocal cord was recorded. Transient symptomatic hypocalcaemia was detected in 9% of the thyroidectomy group (8/90 patients). At follow‐up, 86% of patients showed either no change or improved QoL. About 14% of patients complained of deteriorated QoL, regardless of the extent of surgery. Socio‐economic factors did not influence postoperative QoL.

Conclusions

Results indicate that in pre‐operative consultation of patients with benign goitre, the improvement of QoL should be taken into account for decision‐making in cases of ambiguous surgical indication. Contrary to current discussions that too much thyroid surgery is performed in Germany, we can recommend presenting surgery as an equivalent option to watchful waiting as QoL is at least preserved or improved. The extension of the resection should, however, be decided individually.
Differential gene expression changes in the dorsal root versus trigeminal ganglia following peripheral nerve injury in rats
Authors: Korczeniewska Olga A. , Katzmann Rider Giannina , Gajra Sheetal , Narra Vivek , Ramavajla Vaishnavi , Chang Yun‐Juan , Tao Yuanxiang , Soteropoulos Patricia , Husain Seema , Khan Junad , Eliav Eli , Benoliel Rafael
Published: February 2020

Background

The dorsal root (DRG) and trigeminal (TG) ganglia contain cell bodies of sensory neurons of spinal and trigeminal systems, respectively. They are homologs of each other; however, differences in how the two systems respond to injury exist. Trigeminal nerve injuries rarely result in chronic neuropathic pain (NP). To date, no genes involved in the differential response to nerve injury between the two systems have been identified. We examined transcriptional changes involved in the development of trigeminal and spinal NP.

Methods

Trigeminal and spinal mononueropathies were induced by chronic constriction injury to the infraorbital or sciatic nerve. Expression levels of 84 genes in the TG and DRG at 4, 8 and 21 days post‐injury were measured using real‐time PCR.

Results

We found time‐dependent and ganglion‐specific transcriptional regulation that may contribute to the development of corresponding neuropathies. Among genes significantly regulated in both ganglia Cnr2, Grm5, Htr1a, Il10, Oprd1, Pdyn, Prok2 and Tacr1 were up‐regulated in the TG but down‐regulated in the DRG at 4 days post‐injury; at 21 days post‐injury, Adora1, Cd200, Comt, Maob, Mapk3, P2rx4, Ptger1, Tnf and Slc6a2 were significantly up‐regulated in the TG but down‐regulated in the DRG.

Conclusions

Our findings suggest that spinal and trigeminal neuropathies due to trauma are differentially regulated. Subtle but important differences between the two ganglia may affect NP development.

Significance

We present distinct transcriptional alterations in the TG and DRG that may contribute to differences observed in the corresponding mononeuropathies. Since the trigeminal system seems more resistant to developing NP following trauma our findings lay ground for future research to detect genes and pathways that may act in a protective or facilitatory manner. These may be novel and important therapeutic targets.
Phase Modulation and Chemical Activation of MoSe2 by Phosphorus for Electrocatalytic Hydrogen Evolution Reaction
Authors: Chen Lunfeng , Zhu Yuanmin , Li Jun , Feng Hanghang , Li Tingya , Zhang Xueyan , Wang Suhang , Gu Meng , Zhang Peixin , Zhao Chenyang
Published: February 2020

Molybdenum diselenide (MoSe2), as a member of transitional metal chalcogenides (TMDs), is regarded as a promising electrocatalyst for hydrogen evolution reaction (HER). However, its intrinsic performance is still hampered by insufficient exposure of active sites and inferior electric conductivity. The phase‐engineered synthesis of stable metallic 1T‐MoSe2 with abundant active sites is thus highly desirable for further boosting HER performance. Herein, a phosphorus (P)‐doped MoSe2 with controlled 2H/1T heterophases is synthesized through a facile way. Combining calculations and experiments, it is demonstrated that the doping of P (≈0.83 wt%) not only induces a phase change from 2H to 1T, but activates the Se atoms in the basal plane, thereby significantly enhancing its intrinsic HER performance. An overpotential of 174 mV is achieved at the benchmark of 10 mA cm−2 with a Tafel slope of 51 mV dec−1. More importantly, after the long‐term run at 180 mV for 10 h, the P‐1T/2H‐MoSe2 still displays a high current density of 10.43 mA cm−2 and keeps its original 2H/1T heterostructures, showing superior electrochemical stability and structural robustness. This work provides a facile method for improving the intrinsic HER activity of MoSe2 through nonmetal doping, which helps to understand the activity origin of MoSe2.
Solar Reactor Demonstration of Efficient and Selective Syngas Production via Chemical‐Looping Dry Reforming of Methane over Ceria
Authors: Warren Kent J. , Carrillo Richard J. , Greek Benjamin , Hill Caroline M. , Scheffe Jonathan R.
Published: February 2020

Technologies that facilitate the conversion of CH4 and/or CO2 with concentrated sunlight provide a viable strategy for storing solar energy in the form of liquid fuels and reducing anthropogenic greenhouse gas emissions. Herein, a scalable prototype receiver‐reactor is developed to experimentally demonstrate the chemical‐looping, dry reforming of methane over ceria with simulated concentrated solar radiation. Optimal operating conditions are identified by investigating wide ranges of parameters like temperature, gas flowrate, inlet CH4 concentration, initial oxygen nonstoichiometry, and particle size. Ultimately, a selectivity to H2 and CO of greater than 0.93 is observed at reactant conversions of 0.69 and 0.88 for CH4 and CO2, respectively. As a result, the calorific value of the products relative to the reactants is upgraded, and a solar‐to‐fuel conversion efficiency of 10.06% is attained, higher than the previously reported record of 7%. Near‐perfect selectivity to syngas is achieved by operating with low reactant residence times, and if reactions were initiated over oxygen‐deficient ceria. Reactant conversion is enhanced through a reduction in particle size, which enables more rapid kinetics via an increase in surface oxygen availability. Stable performance is demonstrated over 10 consecutive redox cycles under conditions that maximized efficiency for the system presented herein.
Metal–Organic Framework–Impregnated Calixarene‐Based Cluster‐Derived Hierarchically Porous Bimetallic Phosphide Nanocomposites for Efficient Water Splitting
Authors: Xu Yuwei , Xu Leqiong , Li Qipeng , Su Kongzhao , Hu Yue , Miao Tingting , Qian Jinjie
Published: February 2020

Herein, a new type of multiwalled carbon nanotube anchored on hierarchically porous metal–organic framework (MOF)‐derived bimetallic phosphide composites (M16‐ZIF‐67‐CNT‐P) is reported, which is calcined from the 16‐nuclear calixarene‐based clusters together with typical ZIF‐67 polyhedra through a stepwise pyrolysis strategy. The as‐obtained M16‐ZIF‐67‐CNT‐P sample possesses large specific surface area, quick ion diffusion, high electrical conductivity, and abundant exposed active sites, which exhibits the highest electrocatalytic capability in comparison with the control counterparts. Meanwhile, this type of nanocomposite possesses a superb anodic oxygen evolution reaction (OER) performance requiring 260 mV for 10 mA cm−2. Overall, MOF‐impregnated clusters–derived M16‐ZIF‐67‐CNT‐P exhibits an efficient water splitting performance. This method can be further extended into other systems of high‐nuclear clusters with MOF materials for energy conversion and storage applications.
Provable secure lightweight attribute‐based keyword search for cloud‐based Internet of Things networks
Authors: Ali Mohammad , Sadeghi Mohammad‐Reza
Published: February 2020

As more data from Internet of Things (IoT) devices is outsourced to cloud service providers, the need for secure and efficient fine‐grained access control and data retrieving mechanisms will be increasingly pressing. Attribute‐based keyword search (ABKS) is a promising tool to provide the required infrastructures. However, most of the existing ABKS schemes suffer from expensive computational overhead on the user side. This feature makes such schemes unsuitable for IoT applications as IoT devices usually have limited computational resources. To address this problem, we design a lightweight ABKS scheme called LW‐ABKS. In our scheme, by performing a constant number of efficient computational operations, a data owner can generate a searchable ciphertext. Indeed, in generating a searchable ciphertext, the number of operations performed by data owners modeling IoT devices does not depend on the number of attributes in the access control policy. Moreover, in LW‐ABKS, an authorized data user can retrieve the outsourced data files by performing very lightweight computational operations. We also provide security definitions for the new primitive and prove its security in the standard model and under the hardness assumption of the discrete logarithm and the decisional bilinear Diffie‐Hellman problems.
New use of psychotropic medication after hospitalization among people with dementia
Authors: Möllers Tobias , Perna Laura , Stocker Hannah , Ihle Peter , Schubert Ingrid , Schöttker Ben , Frölich Lutz , Brenner Hermann
Published: February 2020

Objectives

Psychotropic medication is commonly used among people with dementia (PWD), but it shows modest efficacy and it has been associated with severe adverse events. Hospitalizations are an opportunity for medication management as well as treatment recommendations for outpatient physicians. The aim of this study was to asses factors associated with new use of psychotropic medication after hospitalization among PWD.

Methods

We conducted a retrospective dynamic cohort study from 2004 to 2015 using claims data from a German health insurance company. PWD were identified by an algorithm that included ICD‐10 diagnosis and diagnostic measures. The medication classes included were antidepressants, antipsychotics, anxiolytics or hypnotics/sedatives, and Alzheimer's medication. The assessment period was up to 30 days after discharge from the hospital across four hospitalizations.

Results

The main predictors for new use of psychotropic medication were similar across medication classes. Neuropsychiatric symptoms (NPS) and the need of care were associated with higher odds of new use of antidepressants, antipsychotics, and anxiolytics or hypnotics/sedatives. A hospital stay due to dementia was an independent predictor for new use across medication classes as well. Delirium increased the odds for new use of antipsychotics and anxiolytics or hypnotics/sedatives.

Conclusions

Factors associated with new use of psychotropic medication included delirium, NPS, and the need of care in PWD. The findings highlight the need for preventive interventions and non‐medical treatment options in regards to delirium and NPS as well as for a more intensive use of screening tools for inappropriate medication use among PWD.

Key points

The percentage of new users was 1.8%, 7.1%, 2.1%, and 2.5% across hospitalizations for antidepressants, antipsychotics, anxiolytics or hypnotics/sedatives, and Alzheimer's medication, respectively.

83.0%, 61.9%, 56.9%, and 88.1% of new users received antidepressants, antipsychotics, anxiolytics or hypnotics/sedatives, and Alzheimer's medication for more than 6 weeks.

Delirium and neuropsychiatric symptoms were associated with significantly increased odds of new psychotropic medication use.

Hospital stays due to dementia and the need of care were predictors for new use of psychotropic medication.
Tehran stock exchange prediction using sentiment analysis of online textual opinions
Authors: Hatefi Ghahfarrokhi Arezoo , Shamsfard Mehrnoush
Published: February 2020

We investigate the impact of social media data in predicting the Tehran Stock Exchange variables for the first time. We consider the closing price and daily return of three different stocks for this investigation. We collected our social media data from Sahamyab.com/stocktwits for about 3 months. To extract information from online comments, we propose a hybrid sentiment analysis approach that combines lexicon‐based and learning‐based methods. Since lexicons that are available for the Persian language are not practical for sentiment analysis in the stock market domain, we built a particular sentiment lexicon for this domain. After designing and calculating daily sentiment indices using the sentiment of the comments, we examine their impact on the baseline models that only use historical market data and propose new predictor models using multi‐regression analysis. In addition to the sentiments, we also examine the comments volume and the users' reliabilities. We conclude that the predictability of various stocks in the Tehran Stock Exchange is different depending on their attributes. Moreover, we indicate that only comments volume could be useful for predicting the closing price, and both the volume and the sentiment of the comments could be useful for predicting the daily return. We demonstrate that users' trust coefficients have different behaviours toward the three stocks.
Development a flexible light‐sheet fluorescence microscope for high‐speed 3D imaging of calcium dynamics and 3D imaging of cellular microstructure
Authors: Sparks Hugh , Dvinskikh Liuba , Firth Jahn M. , Francis Alice J. , Harding Sian E. , Paterson Carl , MacLeod Ken T. , Dunsby Chris
Published: February 2020

We report a flexible light‐sheet fluorescence microscope (LSFM) designed for studying dynamic events in cardiac tissue at high speed in 3D and the correlation of these events to cell microstructure. The system employs two illumination‐detection modes: the first uses angle‐dithering of a Gaussian light sheet combined with remote refocusing of the detection plane for video‐rate volumetric imaging; the second combines digitally‐scanned light‐sheet illumination with an axially‐swept light‐sheet waist and stage‐scanned acquisition for improved axial resolution compared to the first mode. We present a characterisation of the spatial resolution of the system in both modes. The first illumination‐detection mode achieves dual spectral‐channel imaging at 25 volumes per second with 1024 × 200 × 50 voxel volumes and is demonstrated by time‐lapse imaging of calcium dynamics in a live cardiomyocyte. The second illumination‐detection mode is demonstrated through the acquisition of a higher spatial resolution structural map of the t‐tubule network in a fixed cardiomyocyte cell.
Preference for free or forced choice in Sumatran orangutans (Pongo abelii)
Authors: Ritvo Sarah E. , MacDonald Suzanne E.
Published: February 2020

Empirical investigations of humans, pigeons, rats, and monkeys have indicated that these species will select free over forced choice, even when faced with identical outcomes. However, the same has yet to be quantitatively confirmed in nonhuman great apes. This experiment is the first systematic investigation of preference for free or forced choice in great apes using a paradigm in which extraneous variables are highly controlled. Three orangutans were given a choice of one of two virtual routes, one that provided a choice and one that did not via a touchscreen computer program. Choice of either route was rewarded with the same type and quantity of food. Initial results indicated a preference for free choice across all three participants. However, in two control conditions, orangutans' preferences varied, suggesting a weaker tendency to exercise choice than species previously tested. We suggest further investigation of preference for free and forced choice in orangutans and other great apes through alternative experimental paradigms that focus on increasing the fidelity of free and forced choice options.
Low independence number and Hamiltonicity implies pancyclicity
Authors: Dankovics Attila
Published: February 2020

A graph on vertices is called pancyclic if it contains a cycle of every length . Given a Hamiltonian graph with independence number at most , we are looking for the minimum number of vertices that guarantees that is pancyclic. The problem of finding was raised by Erdős in 1972, who showed that and conjectured that . Improving on a result of Lee and Sudakov, we show that .
Synthesis of benzo[b]xanthene‐triones and tetrahydrochromeno[2,3‐b]xanthene tetraones via three‐ or pseudo–five‐component reactions using Fe3O4@SiO2/PEtOx as a novel, magnetically recyclable, and eco‐friendly nanocatalyst
Authors: Rahnamafar Reyhaneh , Moradi Leila , Khoobi Mehdi
Published: February 2020

In this study, poly(2‐ethyl‐2‐oxazoline) (PEtOx) immobilized on Fe3O4 nanoparticles (Fe3O4@SiO2/PEtOx) has been constructed as a new, heterogeneous, efficient, and recyclable nanocatalyst. The prepared nanocatalyst was characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), powder X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDS) analysis, and vibrating‐sample magnetometer (VSM) techniques. Nanocatalyst was employed to synthesize benzo[b]xanthene‐triones and tetrahydrochromeno[2,3‐b]xanthene tetraones via one‐pot three‐ or pseudo–five‐component reaction between 2‐hydroxy‐1,4‐naphthoquinone or 2,5‐dihydroxy‐1,4‐benzoquinone, aldehyde, and dimedone or 1,3‐cyclohexanedione under reflux condition in ethanol. The catalyst could be easily separated and recycled several times without considerable loss of activity. Clean methodology, easy work‐up, mild reaction condition, short reaction time with good‐to‐excellent yields, and simple preparation of the catalyst are some advantages of the presented work.
Modulating antibiotic release from reservoirs in 3D‐printed orthopedic devices to treat periprosthetic joint infection
Authors: Allen Brian , Moore Christina , Seyler Thorsten , Gall Ken
Published: February 2020

Periprosthetic joint infection is a costly debilitating affliction following total joint arthroplasty. Despite a relatively low incidence rate, periprosthetic joint infection is an increasing problem due to a substantial increase in arthroplasty surgeries over time. The current treatment is replacing the primary implant with a temporary bone cement spacer that releases antibiotics over time. However, the spacer is mechanically weak with an ineffective antibiotic release. Alternatively, three‐dimensional (3D)‐printed reservoirs in high‐strength devices have the potential to release antibiotics long term in a controlled manner. In this study, 3D‐printed reservoirs were loaded with calcium sulfate embedded with gentamicin. In vitro antibiotic release is tuned by varying reservoir parameters, such as channel length, diameter, and quantity. In addition, a straightforward computational model effectively predicts antibiotic release curves to rapidly design devices with a preferred release profile. Overall, this study highlights a novel approach to potentially develop high‐strength joint implants with the long‐term effective release of antibiotics to treat the periprosthetic joint infection.
Synthesis of molecularly imprinted polymer adsorbents for solid‐phase extraction of strobilurin fungicides from agricultural products
Authors: Li Xinyi , Cao Xiaolin , Zhang Zheng , Zhang Ziping , Jiang Zejun , Yin Jungang
Published: February 2020

Molecularly imprinted polymers for strobilurin fungicides were prepared by precipitation polymerization employing azoxystrobin as template molecular together with methacrylic acid monomer and trimethylolpropane triacrylate cross‐linker. Morphological characterization showed molecularly imprinted polymers were uniform spherical particles with about 0.2 μm in diameter, while the morphologies of nonimprinted polymers were irregular bulk. The equilibrium binding and selective experiments proved that molecularly imprinted polymers possessed a higher affinity toward four fungicides compared to nonimprinted polymers and heterogeneous binding sites were found in the molecularly imprinted polymers. Molecularly imprinted solid‐phase extraction conditions, including sample loading solvents, selective washing, and elution solvents, were carefully optimized. The developed method showed good recoveries (70.0–114.0%) with relative standard deviations in range of 1.0–9.8% (n  =  3) for samples (cucumber and peach) spiked at three different levels (10, 50, and 100 μg/ kg). The detection limit (signal/noise = 3) ranged from 0.01 to 0.08 μg/kg. The results demonstrated good potential use of this convenient and highly efficient method for determining trace strobilurin fungicides in agricultural products.
Optimization of thin film solid phase microextraction and data deconvolution methods for accurate characterization of organic compounds in produced water
Authors: Emmons Ronald V. , Liden Tiffany , Schug Kevin A. , Gionfriddo Emanuela
Published: February 2020

The continued rise in the extraction of unconventional oil and gas across the globe poses many questions about how to manage these relatively new waste‐streams. Produced water, the primary waste by‐product, contains a diverse number of anthropogenic additives together with the numerous hydrocarbons extracted from the well. Due to potential environmental hazards, it is critical to characterize the chemical composition of this type of waste before proper disposal or remediation/reuse. In this work, a thin film solid phase microextraction approach was developed and optimized to characterize produced water. The thin film device consisted of hydrophilic‐lipophilic balance particles embedded in polydimethylsiloxane and immobilized on a carbon mesh surface. These devices were chosen to provide broad extraction coverage and high reusability. Various parameters were evaluated to ensure reproducible results while minimizing analyte loss. This optimized protocol, consisting of a 15 min extraction followed by a short (3 s) rinsing step, enabled the reproducible analysis of produced water without any sample pretreatment. Extraction efficiency was suitable for both produced water additives and hydrocarbons. The developed approach was able to tentatively identify a total of 201 compounds from produced water samples, by using one‐dimensional gas chromatography hyphenated to mass spectrometry and data deconvolution.
Soil‐atmosphere exchange of greenhouse gases from typical subalpine forests on the eastern Qinghai‐Tibetan Plateau: Effects of forest regeneration patterns
Authors: Liu Shun , Luo Da , Cheng Ruimei , Yang Hongguo , Wu Jiamei , Shi Zuomin
Published: February 2020

Forest regeneration plays an important role in the carbon (C) and nitrogen (N) budget after clear‐cutting. Nonetheless, the effects of regeneration pattern on soil‐atmosphere exchange of greenhouse gases (GHG; CO2, CH4 and N2O) remain poorly understood on the eastern Qinghai‐Tibetan Plateau. This study reports measured field layer GHG fluxes from Picea asperata broadleaved mixed forest (MF, mixed forests with planted P. asperata and natural regeneration of broadleaved species), natural secondary forest (NF, natural without assisted regeneration), and P. asperata plantation forest (PF, artificial planting) to investigate the influence of regeneration patterns on soil GHG fluxes. The soils of the three forest types acted as CO2 and N2O sources and CH4 sinks. The seasonal variation in GHG fluxes was related to soil temperature, rather than soil moisture. Forest types originating from different regeneration processes exhibited different gaseous C fluxes (CO2 and CH4), but did not exhibit significant effect on N2O emissions. NF and MF had higher CO2 emissions than PF. The difference was related to soil C and N density, NH4+ concentration, and soil β‐glucosidase activity, rather than the soil microbial community. NF had higher CH4 uptake than the other two forest types, which is possibly related to specific individual phospholipid fatty acids. Overall, forest types differing in regeneration patterns had a significant impact on the C balance from the perspective of soil‐atmosphere exchange of gaseous C at our site. Therefore, the GHG fluxes should be considered when taking measures of forest management and regeneration practices in this region.
Elevational differences in the net primary productivity response to climate constraints in a dryland mountain ecosystem of northwestern China
Authors: Xu Hao‐jie , Zhao Chuan‐yan , Wang Xin‐ping
Published: February 2020

Dryland mountain ecosystems regulate global terrestrial carbon cycling and show high sensitivity to climate variability. The Qilian Mountains (QLMs) typify dryland mountain ranges in northern temperate belts and offer fundamental ecosystem services including forage production and water conservation. However, dominant controls on the interannual trend and variability of net primary productivity (NPP) in this region are unknown. Thus, we examined magnitude and direction of the NPP trend and quantified NPP sensitivity to temperature and precipitation under different biomes and altitudes using ground and remote sensing data. Our results showed that 12% of the QLMs had a reversed NPP trend from increasing to decreasing from 2000 to 2016, particularly in the western and southern parts, where NPP reductions were related to precipitation deficits. About 34% of the QLMs showed accelerated or persistent increasing NPP trends, mainly from the mid‐altitude between 3,100 and 4,300 m. The growth rate of NPP was higher in deserts and grasslands than in forests and increased in deserts but decreased in forests and grasslands with increasing elevation. Precipitation showed a stronger effect on the interannual variability in NPP than temperature did. The temperature sensitivity of NPP was similar along elevation gradients in forest steppes but decreased with increasing elevation in alpine deserts. The precipitation sensitivity of NPP reached highest in shrubby meadows when compared with coniferous forests and alpine deserts. This research provides new insights into climate controls of the NPP over the QLMs and to present drought as a growing threat to shrubby meadows and alpine deserts.
Higher dimensional Calabi–Yau manifolds of Kummer type
Authors: Burek Dominik
Published: February 2020

Based on Cynk–Hulek method from [7] we construct complex Calabi–Yau varieties of arbitrary dimensions using elliptic curves with an automorphism of order 6. Also we give formulas for Hodge numbers of varieties obtained from that construction. We shall generalize the result of [11] to obtain arbitrarily dimensional Calabi–Yau manifolds which are Zariski in any characteristic .
Principles and current strategies targeting metallo‐β‐lactamase mediated antibacterial resistance
Authors: Yan Yu‐Hang , Li Gen , Li Guo‐Bo
Published: February 2020

Resistance to β‐lactam antibacterials is commonly associated with the production of the serine β‐lactamases (SBLs) and/or metallo‐β‐lactamases (MBLs). Although clinically useful inhibitors for the SBLs have been developed, no equivalent inhibitors are available for the MBLs, which can hydrolyze almost all β‐lactam antibiotics, including the so‐called “last resort” carbapenems. It is still a challenging task to develop a clinically useful inhibitor that should be broad‐spectrum targeting multiple clinically relevant MBL enzymes that differ in their active site features. This review provides a detailed description of interaction modes of substrates and small‐molecule inhibitors with various MBL enzymes and highlights the importance of metal‐ and “anchor residue”‐binding features to achieve broad‐spectrum MBL inhibition. Recently emerging active site interference strategies include metal ion deprivation, metal ion replacement, and cysteine modification as challenging, but worth experimenting directions for inhibitor development. The metalloenzyme selectivity, metal‐binding pharmacophore, and cellular permeability and accumulation should be properly considered in the further development of clinically useful inhibitors to combat MBL‐mediated antibacterial resistance.
A hybrid calibration approach to Hertz‐type contact parameters for discrete element models
Authors: Qu Tongming , Feng Yuntian , Zhao Tingting , Wang Min
Published: February 2020

This study aims at providing a hybrid calibration framework to estimate Hertz‐type contact parameters (particle‐scale shear modulus and Poisson ratio) for both two‐dimensional and three‐dimensional discrete element modelling (DEM). On the basis of statistically isotropic granular packings, a set of analytical formulae between macroscopic material parameters (Young modulus and Poisson ratio) and particle‐scale Hertz‐type contact parameters for granular systems are derived under small‐strain isotropic stress conditions. However, the derived analytical solutions are only estimated values for general models. By viewing each DEM modelling as an implicit mathematical function taking the particle‐level parameters as independent variables and employing the derived analytical solutions as the initial input parameters, an automatic iterative scheme is proposed to obtain the calibrated parameters with higher accuracies. Considering highly nonlinear features and discontinuities of the macro‐micro relationship in Hertz‐based discrete element models, the adaptive moment estimation algorithm is adopted in this study because of its capacity of dealing with noise gradients of cost functions. The proposed method is validated with several numerical cases including randomly distributed monodisperse and polydisperse packings. Noticeable improvements in terms of calibration efficiency and accuracy have been made.
Mechanically‐Driven Vase–Kite Conformational Switch in Cavitand Cross‐Linked Polyurethanes
Authors: Torelli Martina , Terenziani Francesca , Pedrini Alessandro , Guagnini Francesca , Domenichelli Ilaria , Massera Chiara , Dalcanale Enrico
Published: February 2020

The eligibility of tetraquinoxaline cavitands (QxCav) as molecular grippers relies on their unique conformational mobility between a closed (vase) and an open (kite) form, triggered in solution by conventional stimuli like pH, temperature and ion concentration. In the present paper, the mechanochemical conformational switching of ad hoc functionalized QxCav covalently embedded in an elastomeric polydimethylsiloxane and in a more rigid polyurethane matrix is investigated. The rigid polymer matrix is more effective in converting mechanical force into a conformational switch at the molecular level, provided that all four quinoxaline wings are covalently connected to the polymer.
A case of carcinoma ex pleomorphic adenoma occurred in the sublingual gland
Authors: Yagihara Kazuhiro , Ishii Junichi , Shibata Mari , Anzai Eri , Yagishita Hisao , Ishikawa Ayataka
Published: February 2020

Carcinoma ex pleomorphic adenoma is a malignant salivary gland mixed tumor arising from an existing pleomorphic adenoma (PA). Less than 1% of cases occur in the sublingual gland. Salivary gland duct carcinomas (SDCs) also exhibit invasive development and are rarely found as a microinvasive lesion. A 47‐year‐old man complained of swelling of the oral floor during general dental treatment and was referred to our department. Excision was performed, and we histopathologically determined an early stage of SDC ex PA confirmed in the PA. Tumor from sublingual gland should be carefully treated in consideration of malignancy.
Distributed event‐triggered tracking control with a dynamic leader for multiple Euler‐Lagrange systems under directed networks
Authors: Xu Tao , Duan Zhisheng , Sun Zhiyong , Zhang Zhao
Published: February 2020

The distributed tracking control for multiple Euler‐Lagrange systems with a dynamic leader is investigated in this article via the event‐triggered approach. Only a portion of followers have access to the leader, and the communication topology among all agents is directed that contains a directed spanning tree rooted at the leader. The case that the leader's generalized velocity is constant is first considered, and a distributed event‐based control law is developed by using a velocity estimator. When the leader's generalized velocity is time‐varying, novel distributed continuous estimators are proposed to avoid the undesirable chattering effect while guaranteeing that the estimate errors converge to zeros. With the designed distributed estimators, another distributed event‐based control protocol is provided. Controller update frequency and resource consumption in our work can be reduced by applying the aforementioned two distributed control laws, and the tracking errors can converge to zeros. In addition, it is rigorously proved that no agent exhibits Zeno behavior. Finally, the effectiveness of the proposed distributed event‐based control laws is elucidated by a number of simulation examples.
Interaction analysis under misspecification of main effects: Some common mistakes and simple solutions
Authors: Zhang Min , Yu Youfei , Wang Shikun , Salvatore Maxwell , G. Fritsche Lars , He Zihuai , Mukherjee Bhramar
Published: February 2020

The statistical practice of modeling interaction with two linear main effects and a product term is ubiquitous in the statistical and epidemiological literature. Most data modelers are aware that the misspecification of main effects can potentially cause severe type I error inflation in tests for interactions, leading to spurious detection of interactions. However, modeling practice has not changed. In this article, we focus on the specific situation where the main effects in the model are misspecified as linear terms and characterize its impact on common tests for statistical interaction. We then propose some simple alternatives that fix the issue of potential type I error inflation in testing interaction due to main effect misspecification. We show that when using the sandwich variance estimator for a linear regression model with a quantitative outcome and two independent factors, both the Wald and score tests asymptotically maintain the correct type I error rate. However, if the independence assumption does not hold or the outcome is binary, using the sandwich estimator does not fix the problem. We further demonstrate that flexibly modeling the main effect under a generalized additive model can largely reduce or often remove bias in the estimates and maintain the correct type I error rate for both quantitative and binary outcomes regardless of the independence assumption. We show, under the independence assumption and for a continuous outcome, overfitting and flexibly modeling the main effects does not lead to power loss asymptotically relative to a correctly specified main effect model. Our simulation study further demonstrates the empirical fact that using flexible models for the main effects does not result in a significant loss of power for testing interaction in general. Our results provide an improved understanding of the strengths and limitations for tests of interaction in the presence of main effect misspecification. Using data from a large biobank study “The Michigan Genomics Initiative”, we present two examples of interaction analysis in support of our results.