bluuebunny/crossref_metadata_2025 huggingface dataset:
Interface‐Driven Partial Dislocation Formation in 2D Heterostructures
Authors: Kim Jung Hwa , Kim Se‐Yang , Cho Yeonchoo , Park Hyo Ju , Shin Hyeon‐Jin , Kwon Soon‐Yong , Lee Zonghoon
Published: February 2019

Van der Waals (vdW) epitaxy allows the fabrication of various heterostructures with dramatically released lattice matching conditions. This study demonstrates interface‐driven stacking boundaries in WS2 using epitaxially grown tungsten disulfide (WS2) on wrinkled graphene. Graphene wrinkles function as highly reactive nucleation sites on WS2 epilayers; however, they impede lateral growth and induce additional stress in the epilayer due to anisotropic friction. Moreover, partial dislocation‐driven in‐plane strain facilitates out‐of‐plane buckling with a height of 1 nm to release in‐plane strain. Remarkably, in‐plane strain relaxation at partial dislocations restores the bandgap to that of monolayer WS2 due to reduced interlayer interaction. These findings clarify significant substrate morphology effects even in vdW epitaxy and are potentially useful for various applications involving modifying optical and electronic properties by manipulating extended 1D defects via substrate morphology control.
Polyimide/Graphene Nanocomposite Foam‐Based Wind‐Driven Triboelectric Nanogenerator for Self‐Powered Pressure Sensor
Authors: Zhao Xue , Chen Bo , Wei Guodong , Wu Jyh Ming , Han Wei , Yang Ya
Published: February 2019

Nowadays, aiming to fight against environmental pollution and energy crisis, a great amount of effort has been performed on self‐powered devices. Herein, assembling a wind‐driven triboelectric nanogenerator (TENG) and a pressure sensitive elastic polyimide (PI)/reduced graphene oxide (rGO) foam together, a self‐powered pressure sensor system has been designed and investigated. Employing Ag nanoparticles and nylon film as electrode and vibration membrane, the TENG can generate desirable output. Meanwhile, the PI/rGO foam acts as the pressure sensitive unit. Integrating a bulk of PI/rGO foam (14 mm × 14 mm × 30 mm), the TENG could generate output voltage and current up to 130 V and 7.5 µA with an effective working area of 100 mm × 15 mm. Additionally, the as‐fabricated device presents various stress sensing scopes and sensitivities, when different heights of foams are integrated on the TENG. The self‐powered pressure sensor achieves a great combination between new clean energy resources and traditional pressure sensor.
Quinazoline‐Based Thermally Activated Delayed Fluorecence for High‐Performance OLEDs with External Quantum Efficiencies Exceeding 20%
Authors: Li Bowen , Wang Zhiheng , Su Shi‐Jian , Guo Fengyun , Cao Yong , Zhang Yong
Published: February 2019

The development of new and easily available acceptor moieties for further expansion of the thermally activated delayed fluorecence (TADF) family becomes imperative. In this study, new donor–acceptor TADF materials are designed and synthesized via introducing quinazoline unit as a simple and efficient acceptor for the first time. This is also a typical example of efficient spin–orbit charge transfer coupled between the acceptor triplet (3LEA) and charge transfer singlet (1CT). The small 3LE–1CT gap of 0.09–0.22 eV plays a key role in these four emitters leading to the obvious TADF properties. Moreover, these materials exhibit green to yellow‐green emission and high photoluminescence quantum yield of 67.5–81.0% in the 1,3‐bis(N‐carbazoly)benzene (CBP) host. Organic light‐emitting diodes using the doped emitters exhibit high external quantum efficiency of 16.0–20.5%.
Trifunctional Electrocatalysis on Dual‐Doped Graphene Nanorings–Integrated Boxes for Efficient Water Splitting and Zn–Air Batteries
Authors: Hu Qi , Li Guomin , Li Guodong , Liu Xiufang , Zhu Bin , Chai Xiaoyan , Zhang Qianling , Liu Jianhong , He Chuanxin
Published: February 2019

Despite the exciting achievements made in synthesis of monofunctional electrocatalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), or hydrogen evolution reaction (HER), it is challenging to develop trifunctional electrocatalysts for both ORR/OER/HER. Herein, N, O‐codoped graphene nanorings‐integrated boxes (denoted NOGB) are crafted via high‐temperature pyrolysis and following acid etching of hybrid precursors containing polymers and Prussian blue analogue cubes. The electrochemical results signified that the resulting NOGB‐800 (800 refers to pyrolysis temperature) is highly active for trifunctional electrocatalysis of ORR/OER/HER. This can be reasonably attributed to the advanced nanostructures (i.e., the hierarchically porous nanostructures on the hollow nanorings) and unique chemical compositions (i.e., N, O‐codoped graphene). More attractively, the rechargeable Zn–air battery based on NOGB‐800 displays maximum power density of 111.9 mW cm−2 with small charge–discharge potential of 0.72 V and excellent stability of 30 h, comparable with the Pt/C+Ir/C counterpart. The NOGB‐800 could also be utilized as bifunctional electrocatalysts for overall water splitting to yield current density of 10 mA cm−2 at a voltage of 1.65 V, surpassing most reported electrocatalysts. Therefore, the NOGB‐800 is a promising candidate instead of precious metal–based electrocatalysts for the efficient Zn–air battery and water splitting.
Hydrated Intercalation for High‐Performance Aqueous Zinc Ion Batteries
Authors: Shin Jaeho , Choi Dong Shin , Lee Hyeon Jeong , Jung Yousung , Choi Jang Wook
Published: February 2019

Aqueous zinc ion batteries (AZIBs) are steadily gaining attention based on their attractive merits regarding cost and safety. However, there are many obstacles to overcome, especially in terms of finding suitable cathode materials and elucidating their reaction mechanisms. Here, a mixed‐valence vanadium oxide, V6O13, that functions as a stable cathode material in mildly acidic aqueous electrolytes is reported. Paired with a zinc metal anode, this material exhibits performance metrics of 360 mAh g−1 at 0.2 A g−1, 92% capacity retention after 2000 cycles, and 145 mAh g−1 at a current density of 24.0 A g−1. A combination of experiments and density functional theory calculations suggests that hydrated intercalation, where water molecules are cointercalated with Zn ions upon discharge, accounts for the aforementioned electrochemical performance. This intercalation mechanism facilitates Zn ion diffusion throughout the host lattice and electrode–electrolyte interface via electrostatic shielding and concurrent structural stabilization. Through a correlation of experimental data and theoretical calculations, the promise of utilizing hydrated intercalation as a means to achieve high‐performance AZIBs is demonstrated.
Palladium‐Catalyzed C−H Arylation of Aliphatic and Aromatic Ketones using Dipeptide Transient Directing Groups
Authors: Cheng Yaohang , Zheng Jie , Tian Chao , He Yuhang , Zhang Cong , Tan Qi , An Guanghui , Li Guangming
Published: February 2019

Ketones are ubiquitous structural motifs in chemical materials and medicinally active pharmaceutical ingredients. Transition metal‐catalyzed C−H bond functionalization is one of the most efficient tactics for diversification of ketones. Palladium‐catalyzed C−H arylation of aliphatic and aromatic ketones has been achieved utilizing an inexpensive dipeptide as a transient directing group. The tridentate coordination used in this reaction enhances the reactivity of the substrates and allows reduction of the loading of the directing group compounds to 20%. This approach allows rapid arylation of complex natural products, medicinal‐chemistry‐related scaffolds, and even remote C(sp2)−H bonds.
Standard methods for creating digital skeletal models using structure‐from‐motion photogrammetry
Authors: Morgan Brianne , Ford Andrew L.J. , Smith Martin J.
Published: February 2019

Objectives

This article assesses best practices for producing 3D digital cranial models through structure‐from‐motion (SfM) photogrammetry, and whether the metric accuracy and overall presentation of photogrammetric models are comparable to physical crania. It is intended to present a user‐friendly standard method of creating accurate digital skeletal models using Agisoft PhotoScan.

Materials and methods

Approximately 200 photographs were taken of three different crania, and were separated into series consisting of 50, 75, 100, 150, and approximately 200 photos. Forty‐five cranial models were created using different photo series and a variety of PhotoScan settings. These models were assessed based on defined qualitative criteria, and model measurement estimates were compared with physical skeletal measurements using Bland–Altman plots.

Results

The majority of all models (37/45) produced measurement estimates with mean differences of 2 mm or less regardless of PhotoScan settings, and therefore demonstrated high levels of agreement with the physical measurements. Models created with 150 photographs and on “high” PhotoScan settings scored the highest in terms of qualitative appearance in the shortest amount of time.

Discussion

In PhotoScan, it is recommended to create cranial models using 150 photographs and “high” settings; this produces digital cranial models that are comparable to physical crania in both appearance and proportion. SfM photogrammetry is a convenient, noninvasive, and rapid 3D modeling tool that can be used in almost any setting to produce digital models, and following the guidelines established here will ensure that these models are metrically accurate.
Functionalization of multi‐walled carbon nanotubes by the baclofen drug to immobilize palladium nanoparticles and catalyze Sonogashira coupling reactions
Authors: Nazari Pooneh , Hekmati Malak
Published: February 2019

The baclofen‐MWCNTs‐Pd nanocatalyst was synthesized through covalent grafting of baclofen molecules onto surface‐modified carbon nanotubes and immobilizing Pd nanoparticles by the baclofen ligands. The chemical structure of the produced nanocatalyst was studied by Raman spectroscopy, Fourier transform‐infrared spectroscopy, energy‐dispersive spectroscopy (EDS), elemental mapping and inductively coupled plasma analysis. Also, its surface morphology was determined using the scanning and transmission electron microscopy techniques. Furthermore, the obtained baclofen‐MWCNTs‐Pd nanocatalyst is demonstrated to exhibit very high activity as a heterogeneous phosphine‐free catalyst in Sonogashira cross‐coupling of aryl halides by giving good to excellent yields of different products. In addition, the nanocatalyst can be reused four times without any significant leaching or loss of activity.
Stability of polyethylenimine solution‐in‐liquid paraffin emulsion for preparing polyamine microspheres with potential adsorption for ionic dyes
Authors: Huang Dengfa , Wang Feng , Zhu Jingwen , Pei Xiaomei
Published: February 2019

A microsphere synthesized by emulsion crosslinking of polyethylenimine (PEI) was applied in the removal of ionic dyes from water. Firstly, the stability of the PEI solution‐in‐liquid paraffin emulsion was improved by using the mixture of Span‐80/Tween‐80 as the emulsifier. The optimization by 25‐1 fractional factorial design demonstrated the most stable emulsion was prepared at 0.07 g/mL of the emulsifier dosage, 6:4 (v:v) of the oil/water ratio, 20 % (wt %) of the PEI concentration, 6:1 (w:w) of the Span‐80/Tween‐80 ratio with a homogenization speed of 6000 r/min for 3 min at 25 oC. Then, the polyamine microsphere (PA‐M) was obtained by crosslinking the PEI emulsion with glutaraldehyde. The PA‐M microsphere can adsorb xylenol orange (XO) from aqueous solution with a capacity of 1169.2±12.5 mg/g. The amount of XO adsorption remained constant in the pH range of 2.0‐11.0. Adsorption kinetics analysis demonstrated that Pseudo first‐order model fit the experimental data better, indicating the overall adsorption process was controlled by ‘surface reaction’. The XO adsorption on the microsphere was due to an electrostatic interaction according to the results of ΔG evaluation. The value of separation factor suggested the XO adsorption was favorable. The used PA‐M microsphere can be regenerated and reused in adsorption/desorption operation at least 20 times.
Surface Functionalization of Magnetite Nanoparticles with Sulfonic Acid and Heteropoly Acid: Efficient Magnetically Recoverable Solid Acid Catalysts
Authors: Hosseini Mahdiyeh‐Sadat , Masteri‐Farahani Majid
Published: February 2019

New magnetically recoverable solid acid catalysts for acid‐catalyzed reactions were designed via the surface chemical functionalization of silica‐coated magnetite nanoparticles (SCMNPs) with sulfonic acid groups. First, the SCMNPs were covalently functionalized with 3‐aminopropyl groups to achieve Amp‐SCMNPs. Then, reaction of the Amp‐SCMNPs with 1,4‐butane sultone followed by acidification with phosphotungstic acid (HPW) or diluted sulfuric acid produced magnetically recoverable solid acid catalysts, HPW‐ampsul‐SCMNPs and H‐ampsul‐SCMNPs, respectively. Both catalysts were characterized by various physicochemical analyses such as Fourier transform infrared (FT‐IR) and inductively coupled plasma‐optical emission (ICP‐OES) spectroscopies, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), and energy‐dispersive X‐ray (EDX) analyses. Finally, the catalytic activities of the prepared catalysts were examined in the esterification of acetic acid with butanol and acetalization of benzaldehyde with ethylene glycol. Excellent catalytic efficiencies were obtained in both cases. The catalysts were consecutively recovered and reused five times without significant loss of their activities.
Combination of photoinduced fluorescence and GC–MS for elucidating the photodegradation mechanisms of diflubenzuron and fenuron pesticides
Authors: Diaw Pape A. , Mbaye Olivier M.A. , Thiaré Diene D. , Oturan Nihal , Gaye‐Seye Mame Diabou , Coly Atanasse , Le Jeune Bernard , Giamarchi Philippe , Oturan Mehmet A. , Aaron Jean‐Jacques
Published: February 2019

Diflubenzuron (DFB) and fenuron (FEN) are benzoylurea and phenylurea pesticides, widely used in Senegal, that do not exhibit any natural fluorescence, but can be determined by means of photoinduced fluorescence (PIF) methods. Photodegradation of DFB and FEN yielded a number of fluorescent and non‐fluorescent photoproducts. For both pesticides, at least 10 photoproducts were detected and identified by gas chromatography–mass spectrometry (GC/MS). To identify the formed fluorescent DFB and FEN photoproducts, their fluorescence spectra were compared with those of standard compounds, including phenol and p‐hydroxyaniline.
Carbon dots synthesized by them‐trihydroxybenzene as the carbon source and its application on the detection of pH value
Authors: Peng Xiaoxiao , Li Chenchen , Zhang Yubing , Chen Shu , Long Yunfei
Published: February 2019

New carbon dots (CDs) were prepared by a microwave method usingm‐trihydroxybenzene and dilute sulphuric acid as raw materials. The as‐prepared CDs exhibited excellent water solubility and photoluminesence properties. The optimum excitation and emission wavelengths of the new CDs were at 365 nm and 465 nm, respectively. The fluorescence of the new CDs experienced remarkable changes in the presence of Britton–Robinson (BR) buffer solution with different pH values under 4°C after reacting for 70 min. In addition, a linear relationship between the logarithm of the relative fluorescence intensity ratio [lg(IF/IFo)] of CDs and the pH values of the sensing system ranging 1.81–5.72 was obtained, with a correlation coefficient of 0.9933. Thus, a sensitive and simple method to detect the pH value of solution was developed. Furthermore, the analytical application of detecting the concentration of acetic acid in vinegar was investigated. The detection values were found similar to the reference values, fully demonstrating a good linear relationship between the logarithm of the relative fluorescence intensity ratio of the CDs and the pH value of the system. Hence, the method could be used to detect the concentration of acetic acid in vinegar.
Occupational gaps 5 years after stroke
Authors: Svensson Joel S. , Westerlind Emma , Persson Hanna C. , Sunnerhagen Katharina S.
Published: February 2019

Objectives

To investigate the incidence and number of occupational gaps 5 years after stroke and find possible predictors and explanatory factors for increased number of experienced gaps.

Material and Methods

The participants were diagnosed with first‐time stroke in Gothenburg during 2009–2010. Medical records from their hospital stay were used to obtain baseline data. The Occupational Gaps Questionnaire and the Swedish stroke registers follow‐up questionnaire were sent out. Data from the Occupational Gaps Questionnaire were used as a dependent variable and baseline data and questions from the stroke registry were used as independent variables in logistic regression.

Results

Five years poststroke, 49.5% experienced a higher number of occupational gaps compared to a healthy reference population. Predictors for an increased number of gaps were higher age at stroke onset and a higher degree of functional dependency. Explanatory factors for an increased number of gaps in the study population were higher age at follow‐up and feelings of depression.

Conclusions

Older age at the time of stroke and functional dependency can predict an increased number of occupational gaps. Older age and feelings of depression are connected to an increased number of occupational gaps. Individuals at risk should be provided with additional interventions to reduce participation restrictions.
The impact of perceived corporate social responsibility on employee engagement: The case of Qatar
Authors: Al Amri Fatma H. , Das Amit , Ben‐Ayed Omar
Published: February 2019

This work investigates the role of perceived corporate social responsibility (CSR) in enhancing employee engagement (EE) in the State of Qatar. We collected survey data from local and expatriate employees of government, semigovernment, and private sector Qatari firms on their perceptions of CSR activities undertaken by their employers. The scope of CSR included activities targeted at employees, customers, the government, and society at large (social and nonsocial stakeholders). We also measured two facets of EE: organizational engagement and job engagement. We examined how these dimensions of EE are associated with employees' perception of the firm's CSR activities, controlling for the type of firm (government, semigovernment, or private) and the type of employee (local or expatriate). Our results reveal that CSR to society and CSR to employees affect organizational engagement whereas CSR to customers affects job engagement. CSR to the government is not significantly related to either aspect of EE.
Enhanced expression of ten‐eleven translocation 1 reverses gemcitabine resistance in cholangiocarcinoma accompanied by a reduction in P‐glycoprotein expression
Authors: Wang Chuanxu , Ye Hua , Zhang Lei , Cheng Yayu , Xu Shifeng , Zhang Ping , Zhang Zijie , Bai Jimin , Meng Fangkang , Zhong Lin , Shi Guangjun , Li Hao
Published: February 2019

Increasing evidence revealed that ten‐eleven translocation 1 (TET1) plays an important role in tumorigenesis and chemoresistance, but its functions in gemcitabine resistance in cholangiocarcinoma (CCA) remain unknown. This study aims to investigate the effect of TET1 on gemcitabine resistance in CCA and the possible effect on P‐glycoprotein (P‐gp) expression encoded by multidrug resistance (MDR) genes. We established two kinds of gemcitabine‐resistant CCA cell lines and confirmed its specific features. The expression of TET1 and P‐gp was evaluated in gemcitabine‐resistant CCA cells and their parental cells at mRNA and protein level by quantitative RT‐PCR and western blot analysis. After transfecting the gemcitabine‐resistant CCA cell lines with TET1 gene or siRNA, the cell viability test was obtained to verify the effect of TET1 on the sensitivity of CCA cells to gemcitabine. And then, the possible effect of TET1 on the expression of P‐gp was examined by western blot analysis. Xenograft tumor experiment was conducted to confirm the association between TET1 and P‐gp expression under gemcitabine chemoresistance. The associations between clinical outcomes of CCA patients with chemotherapy and TET1 expression were analyzed in 82 patients. The results showed that TET1 expression was significantly decreased, and P‐gp expression was increased in gemcitabine‐resistant CCA cells. Additionally, overexpression of TET1 augmented the sensitivity of CCA cells to gemcitabine and induced the decreased expression of P‐gp in gemcitabine‐resistant CCA cells. Furthermore, multivariate Cox regression analysis indicated that TET1 expression and TNM stage were independent risk factors (P < 0.001) for the clinical outcomes of CCA patients with chemotherapy. Additionally, Kaplan‐Meier survival and the log‐rank test showed that decreased expression of TET1 was associated with poorer prognosis of CCA patients with chemotherapy. These findings suggest that TET1 expression reverses gemcitabine resistance in CCA accompanied by a reduction in P‐gp expression. Thus, TET1 may be a promising target to overcome chemoresistance in CCA.
Daturanolide A–C, Three New Withanolides from Datura metel L. and Their Cytotoxic Activities
Authors: Wang Xiao‐Yan , He Jun , Bai Hong‐Jin , Gao Pin‐Yi , Gan He , Yang Ting , Zhang Wei‐Ku , Xu Jie‐Kun
Published: February 2019

Three new withanolides (1–3), named as daturanolide A–C, along with six known withanolides (4–9) were isolated from the flowers of Datura metel L. Their structures with absolute configurations were elucidated by a series of spectroscopic methods, electronic circular dichroism (ECD) analyses, and X‐ray crystallography. All the isolates were evaluated for cytotoxicity against five human cancer cell lines (HCT116, U87‐MG, NCI‐H460, BGC823, and HepG2), and 6 exhibited marked cytotoxicity.
Acute lumbar polyradiculoneuropathy as early sign of methotrexate intrathecal neurotoxicity: Case report and literature review
Authors: Montejo Carmen , Navarro‐Otano Judith , Mayà‐Casalprim Gerard , Campolo Michela , Casanova‐Mollá Jordi
Published: February 2019

Key Clinical Message

Acute paraplegia after treatment with intrathecal methotrexate requires a complete spinal cord neuroimaging as well as electrodiagnostic examination. The absence of lumbosacral F waves motor responses without demyelinating findings may indicate early direct root toxicity. Early electromyography (EMG) screening could be a valuable tool for detecting peripheral neurotoxicity.
Nivolumab and immune‐mediated colitis
Authors: Walker Heather , Brennan Paul , Groome Maximillian , Walsh Shaun , Carey Frank
Published: February 2019

Key Clinical Message

Nivolumab is associated with a number of immune‐regulated adverse events, including immune‐mediated colitis and may present following the discontinuation of treatment. Current guidance suggests lower doses of methylprednisolone; however, we described faster resolution of the patient's symptoms compared to previous reported cases, using higher dosing, thereby minimizing hospitalization.
Utility of transoral pharyngeal ultrasonography for puncture drainage of peritonsillar abscess
Authors: Hagiwara Yuta , Araga Takashi , Saito Yoshimitsu , Sasano Yoshiyuki , Tamura Yuki , Shimizu Takahiro , Hasegawa Yasuhiro
Published: February 2019

Key Clinical Message

Puncture drainage is usually needed to treat peritonsillar abscess. However, inadvertent carotid artery puncture may result in devastating complications. Preoperative transoral carotid ultrasonography (TOCU) is useful to delineate the anatomical relationship between the abscess and carotid artery. We present a case of peritonsillar abscess illustrating the utility of TOPU for safe drainage.
Whole‐exome sequencing reveals novel USP9X variant in female fetus with isolated agenesis of the corpus callosum
Authors: Lenberg Jerica L. , Pretorius Dolores H. , Rupe Eric S. , Jones Marilyn C. , Ramos Gladys A. , Andreasen Tara S.
Published: February 2019

Key Clinical Message

Whole‐exome sequencing in a female fetus detected a USP9X variant. This X‐linked gene was recently associated with intellectual disability and distinct pattern of malformation in females. Isolated agenesis of the corpus callosum has not been reported in association with USP9X. Identifying this variant impacted management of the subsequent pregnancy.
A mimic of tachycardia‐bradycardia syndrome in a patient with long‐standing persistent atrial fibrillation
Authors: Sairaku Akinori , Matsumoto Takeshi , Kinoshita Hiroki , Matsumura Hiroya , Oguri Naoto , Morishima Nobuyuki
Published: February 2019

Key Clinical Message

Pause following incessant tachycardia is often encountered in clinical practice. We encountered a rare arrhythmic condition mimicking tachycardia‐bradycardia syndrome. We hereby describe the step‐by‐step diagnostic process.
Use of low dose of rFVIIa (recombinant Factor VII activated) to control late bleeding after percutaneous dilational tracheostomy
Authors: Nicosia Dario , Federico Antonino , Vigna Ivan , Iozzo Pasquale , Misseri Giovanni , Cortegiani Andrea
Published: February 2019

Key Clinical Message

In our case, the use of a low intravenous bolus dose of rFVIIa (recombinant factor VII activated; 15‐20 mcg/kg) was effective and uneventful in controlling late postprocedural PDT bleeding associated with thrombocytopenia that cannot be corrected and after all other treatments failed.
Refractory exudative pleural effusion in patients with chronic kidney disease not receiving dialysis: A case report
Authors: Seo Hye Mi , Kim Miyeon , Kim Hyunwoo
Published: February 2019

Key Clinical Message

Although exudative pleural effusion can be caused by infections, malignancies, and connective tissue diseases, we need to consider uremic pleural effusion and pleuritis in differential diagnosis of exudative lymphocyte predominant pleural effusion in patients with chronic kidney disease not receiving dialysis.
One‐Step Preparation of Cobalt‐Nanoparticle‐Embedded Carbon for Effective Water Oxidation Electrocatalysis
Authors: Wu Qian , Li Jian , Wu Tongwei , Ji Lei , Zhang Rong , Jiang Pengfei , Chen Hongyu , Zhao Runbo , Asiri Abdullah M. , Sun Xuping
Published: February 2019

The sluggish kinetics of the oxygen evolution reaction (OER) impedes the whole water splitting efficiency and it is thus highly desirable to develop cost‐effective OER electrocatalysts. In this Communication, we report the one‐step preparation of cobalt‐nanoparticle‐embedded carbon as a superior OER electrocatalyst with a low overpotential of 232 mV to drive a current density of 10 mA cm−2 in 1.0 M KOH. Notably, this catalyst also exhibits excellent long‐term electrochemical stability. The catalytic mechanism is also investigated by density functional theory calculations.
High‐Performance Microwave Absorption of MOF‐Derived Core‐Shell Co@N‐doped Carbon Anchored on Reduced Graphene Oxide
Authors: Liu Lili , Wang Lei , Li Qingqing , Yu Xuefeng , Shi Xiaofeng , Ding Jingjun , You Wenbin , Yang Liting , Zhang Yahong , Che Renchao
Published: February 2019

Nanocomposites of MOF‐derived N‐doped‐carbon‐wrapped cobalt anchored on reduced graphene oxide (Co@NC@RGO) have been successfully fabricated for use as microwave absorption materials. A unique core‐shell nanostructure with cobalt nanoparticles as core and N‐doped graphitized carbon as shell was grown on the surface of laminated reduced graphene oxide (RGO). An enhanced synergistic effect between magnetic and dielectric components can be readily achieved by changing the dispersion of Co@NC nanoparticles on RGO. The as‐synthesized microspheres are composed of numerous nanoscale core‐shell Co@NC units, which combined magnetic Co cores with intrinsically contributing magnetic loss and N‐doped graphitized carbon providing a pathway for electron transfer as well as transition between magnetic Co cores and high electrical conductivity of RGO. The resulting Co@NC@RGO composites exhibit excellent reflection loss (RL) values and effective absorption bandwidths. The optimized Co@NC@RGO‐3 minimum RL (RLmin) value could reach −46.5 dB at 9.4 GHz with a thickness of 3.5 mm. Tuning the thickness from 1.5–5 mm, the effectivity absorption frequency range could achieve up to 14.3 GHz (from 3.7 to 18 GHz). The excellent microwave absorption performance may be attributed to the magnetic loss, dielectric loss and interfacial polarization.
Gel‐ and Solid‐State‐Structure of Dialanine and Diphenylalanine Amphiphiles: Importance of C⋅⋅⋅H Interactions in Gelation
Authors: Farahani Abbas D. , Martin Adam D. , Iranmanesh Hasti , Bhadbhade Mohan M. , Beves Jonathon E. , Thordarson Pall
Published: February 2019

To investigate the role of the capping group in the solution and solid‐state self‐assembly of short peptide amphiphiles, dialanine and diphenylalanine have been linked via the N‐terminus to a benzene (phenyl) and 3‐naphthyl capping groups using three different methylene linkers; (CH2)n, n=0–4 for the benezene and 0, 1 and 2 for the naphthalene capping group. Atomic force microscopy (AFM), oscillatory rheology, circular dichroism (CD), and IR analysis have been employed to understand the properties of these peptide‐based hydrogels. Several X‐ray structures of these short peptide gelators give useful conformational information regarding packing. A comparison of these solid state structures with their gel state properties yielded greater insights into the process of self‐assembly in short peptide gelators, particularly in terms of the important role of C⋅⋅⋅H interactions appear to play in determining if a short aromatic peptide does form a gel or not.
The Counterion Effect of Imidazolium‐Type Poly(ionic liquid) Brushes on Carbon Dioxide Adsorption
Authors: Li Na , Qu Rong , Han Xiaoyu , Lin Weiran , Zhang Haining , Zhang Zhenyu J.
Published: February 2019

Imidazolium‐based poly(ionic liquid) brushes were attached to spherical silica nanoparticles bearing various functionalities by using a surface‐initiated atom transfer radical polymerization (“grafting from” technique). A temperature‐programmed desorption process was applied to evaluate and analyze the carbon dioxide adsorption performance of the synthesized polymer brushes. The confined structure of the surface‐attached polymer chains facilitates gas transport and adsorption, leading to an enhanced adsorption capacity of carbon dioxide molecules compared with pure polymer powders. Temperature‐programmed desorption profiles of the synthesized polymer brushes after carbon dioxide adsorption reveal that the substituent groups on the nitrogen atom at the 3‐position of the imidazole ring, as well as the associated anions significantly affect the adsorption capacity of functionalized poly(ionic liquid) brushes. Of the tested samples, amine‐functionalized poly(ionic liquid) brushes associated with hexafluorophosphate ions exhibit the highest carbon dioxide adsorption capacity of 2.56 mmol g−1 (112.64 mg g−1) at 25 °C under a carbon dioxide partial pressure of 0.2 bar.
Fluorescence pH Probes Based on Photoinduced Electron Transfer Quenching of Long Fluorescence Lifetime Triangulenium Dyes
Authors: Rosenberg Martin , Junker Anne Kathrine R. , Sørensen Thomas Just , Laursen Bo W.
Published: February 2019

Azaoxatriangulenium dyes with long fluorescence lifetimes offer advantages in fluorescence lifetime imaging (FLIM), time‐gated detection and polarization assays. However, the long excited state lifetimes are also expected to increase sensitivity to photoinduced electron transfer (PET) quenching, potentially increasing the on‐off ratio of PET probes. We report the synthesis and investigation of the optical properties of azaoxatriangulenium salts substituted with phenol substituents for pH sensing. Two series of pH probes with the phenol hydroxy group placed in the ortho, meta, or para positions to azadioxatriangulenium (ADOTA) and diazaoxatriangulenium (DAOTA) chromophores are investigated. All the phenol‐substituted dyes possess pH‐responsive fluorescence signals in the biologically relevant pH window (pH 6–9) due to efficient intramolecular PET from the phenolate form of the pendant arm. While the PET mechanism is partly suppressed in the phenol form of the ADOTA derivatives, it is completely suppressed in the DAOTA derivatives. The long excited state lifetimes of the triangulenium dyes ensure efficient PET quenching leading to very high on‐off ratios of the pH probes. The study clearly demonstrates effects of the position of the phenol/phenolate group relative to the chromophore on both PET quenching rates and pKa values.
Biogeography of the xerophytic genus Anabasis L. (Chenopodiaceae)
Authors: Lauterbach Maximilian , Veranso‐Libalah Marie Claire , Sukhorukov Alexander P. , Kadereit Gudrun
Published: February 2019

Aim

Using the extremophile genus Anabasis, which includes c. 28 succulent, xerophytic C4 species, and is widely distributed in arid regions of Northern Africa, Arabia, and Asia, we investigate biogeographical relationships between the Irano‐Turanian floristic region (ITfr) and its neighboring regions. We test whether the spread of arid and semi‐arid biomes in Eurasia coincides with the biogeography of this drought‐adapted genus, and whether the ITfr acted as source area of floristic elements for adjacent regions.

Location

Deserts and semi‐deserts of Northern Africa, Mediterranean, Arabia, West and Central Asia.

Methods

Four cpDNA markers (rpL16 intron, atpB‐rbcL, trnQ‐rps16, and ndhF‐rpL32 spacers) were sequenced for 58 accessions representing 21 Anabasis species. Phylogenetic relationships and divergence times were inferred using maximum likelihood and a time‐calibrated Bayesian approach. To document the extant distribution of Anabasis, material from 23 herbaria was surveyed resulting in 441 well‐documented collections used for the coding of eight floristic regions. Using this coded data, ancestral range was estimated using “BioGeoBEARS” under the DEC model.

Results

Anabasis originated during the Late Miocene and the ancestral range was probably widespread and disjunct between Western Mediterranean and the Irano‐Turanian regions. Diversification started with two divergence events at the Miocene/Pliocene boundary (5.1 and 4.5 mya) leading to Asian clade I with ITfr origin which is sister to a slightly younger Asian clade II, which originated in the Western ITfr, and a Mediterranean/North African clade with an origin in the Western Mediterranean.

Main conclusions

Anabasis did not follow aridification and continuously expanded its distribution area, in fact its probably wide ancestral distribution area seems to have been fragmented during the very Late Miocene and the remnant lineages then expanded into neighboring arid regions. This genus supports the role of the ITfr as source area for xerophytic elements in the Mediterranean and Central Asia.
Moderate fire severity is best for the diversity of most of the pollinator guilds in Mediterranean pine forests
Authors: Lazarina Maria , Devalez Jelle , Neokosmidis Lazaros , Sgardelis Stefanos P. , Kallimanis Athanasios S. , Tscheulin Thomas , Tsalkatis Panagiotis , Kourtidou Marina , Mizerakis Vangelis , Nakas Georgios , Palaiologou Palaiologos , Kalabokidis Konstantinos , Vujic Ante , Petanidou Theodora
Published: February 2019

Fire, a frequent disturbance in the Mediterranean, affects pollinator communities. We explored the response of major pollinator guilds to fire severity, across a fire‐severity gradient at different spatial scales. We show that the abundance of all pollinator groups responded to fire severity, and that bees and beetles showed in addition a significant species‐diversity response. Bees, sawflies, and wasps responded to fire severity at relatively small spatial scales (250–300 m), whereas flies and beetles responded at larger spatial scales. The response of bees, sawflies, and wasps was unimodal, as predicted by the intermediate disturbance hypothesis, whereas flies and beetles showed a negative response. A possible explanation is that the observed patterns (spatial scale and type of response) are driven by taxa‐specific ecological and life‐history traits, such as nesting preference and body size, as well as the availability of resources in the postfire landscape. Our observational study provides an insight into the effect of fire severity on pollinators. However, future research exploring the explicit link between the pre‐ and postfire landscape structure and pollinator traits and responses is required for further establishment and understanding of cause–effect relationships.
Lung diffusion capacity in advanced heart failure: relation to central haemodynamics and outcome
Authors: Deis Tania , Balling Louise , Rossing Kasper , Wolsk Emil , Perch Michael , Gustafsson Finn
Published: February 2019

Aims

Patients with heart failure (HF) are known to have a reduced pulmonary diffusion capacity for carbon monoxide (DLCO), but little is known about how lung function relates to central haemodynamics. The aim of this study was to investigate the association between haemodynamic variables and pulmonary diffusion capacity adjusted for alveolar volume in congestive HF patients and to analyse how predicted DLCO/VA affects mortality in relation to the haemodynamic status.

Methods and results

We retrospectively studied right heart catheterization (RHC) and lung function data on 262 HF patients (mean age 51 ± 13 years) with a left ventricular ejection fraction < 45% referred non‐urgently for evaluation for heart transplantation (HTX) or left ventricular assist device (LVAD). Univariate and multivariate linear regression models were constructed to examine the associations between predicted values of DLCO/VA, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), and haemodynamic parameters [pulmonary capillary wedge pressure (PCWP), central venous pressure, cardiac index, mean pulmonary artery pressure, and mean arterial pressure] as well as other factors known to affect lung function in HF. FEV1 was reduced to <80% of predicted value in 55% of the population, and DLCO/VA was reduced in 63% of the population. DLCO/VA correlated positively with pulmonary capillary wedge pressure in both univariate and multivariate analyses for all included patients (P < 0.001 and P = 0.045, respectively) and a restricted population of patients with the shortest time between RHC and lung function testing (P = 0.005, P = 0.015). DLCO/VA predicted mortality in multivariate models [hazard ratio 1.5 (1.1–2.1)] but not the combined endpoint of death, LVAD implantation, or HTX. There was no significant correlation between haemodynamics and predicted FVC or FEV1.

Conclusions

Pulmonary diffusion capacity correlates positively with left ventricular fillings pressures, and reduced values predict increased mortality in patients with HF. This might be driven by increased lung capillary volume in patients with pulmonary congestion.
Synergistic Effects of Mo2C‐NC@CoxFey Core–Shell Nanoparticles in Electrocatalytic Overall Water Splitting Reaction
Authors: Wang Shiping , Bendt Georg , Saddeler Sascha , Schulz Stephan
Published: February 2019

Transition metals (TMs) are highly investigated as nonprecious electrocatalysts for hydrogen evolution (HER) and oxygen evolution (OER) reactions. There is a strong demand for highly efficient and inexpensive catalysts for overall water splitting. Herein, the bimetallic CoxFey alloy nanoparticles encapsulated in a N‐doped graphene shell containing molybdenum carbide (Mo2C) nanoparticles are synthesized by the pyrolysis of cobalt ferrite (CoxFe3−xO4) nanoparticles coated by melamine‐formaldehyde resin cross‐linked with molybdic acid. Molybdic acid not only serves as precursor for the formation of highly dispersed Mo2C nanoparticles in the N‐doped graphene shell but also enhances the thermal stability of the organic shell, resulting in the formation of smaller CoxFey cores. The formation of Mo2C nanoparticles in the graphene shell is promoted by the CoxFe3−xO4 core. Interestingly, the synergistic presence of Mo2C nanoparticles not only enhances the HER activity of the material but also renders a partial breakage of the graphene shell, which increases the surface concentration of OER‐active Co and therefore enhances the OER activity. The as‐prepared TM‐based materials serve as bifunctional catalysts for the overall water splitting and exhibit improved electrocatalytic performances compared to standard cells based on precious metals, with the potentials of 1.53 and 1.60 V at 10 and 20 mA cm−2 in alkaline media, respectively.
Sputtering as a viable route for In2S3 buffer layer deposition in high efficiency Cu(In,Ga)Se2 solar cells
Authors: Soni Purvesh , Raghuwanshi Mohit , Wuerz Roland , Berghoff Birger , Knoch Joachim , Raabe Dierk , Cojocaru‐Mirédin Oana
Published: February 2019

Alternative buffer layers in CIGSe are deposited mainly using chemical bath deposition because of its benefits like simplicity, good film quality and surface/step coverage. All the layers in CIGSe cell stack such as back contact, absorber and window layers are deposited by vacuum–deposition methods such as coevaporation, sputtering, and sometimes thermal evaporation, except for the buffer layer. Therefore, in the present work we demonstrate the feasibility to deposit In2S3 by RF magnetron sputtering reaching cell efficiencies of 13.6%, which is the highest value available for sputtered In2S3 in literature to date. Absorber surface damage and nonuniform buffer layer thickness are the primary limitations when using sputtering, and hence need to be eliminated for reaching reasonable cell efficiencies. We studied the extent of sputter induced damage on CIGSe absorber as well as the sputtering– and annealing–induced intermixing phenomenon at the In2S3/Cu(In,Ga)Se2 interface at the subnanometer level using atom probe tomography. We have also shown that a post deposition annealing not only significantly improves the crystallinity of In2S3, but also recovers the surface damage caused by sputter‐induced intermixing resulting in an improved p‐n Junction quality (as shown by the electron beam induced current investigations), and substantially improves cell efficiency. The present work opens a new way for designing efficient and industry–compatible CIGSe cells using sputter–deposited Cd‐free buffer layers. Moreover, this work clearly demonstrates that this novel and fully vacuum–deposited CIGSe cell meets the standard requirements, in terms of chemistry, structure, and electrical performance of a working cell for the PV industry.
Effect of surface wettability of ceramic proppant on oil flow performance in hydraulic fractures
Authors: Dong Kanjicai , He Wenhao , Wang Ming
Published: February 2019

Ceramic proppants are critical products for holding induced fractures open and enhancing hydrogen productivity in low‐permeability reservoirs. Though the effects of proppant size and proppant type on the well productivity have been well studied in the past, the role of the proppant surface wettability in the oil flow performance has not been thoroughly investigated. To help the readers and the industries understand the wetting behavior of ceramic proppants, this research was designed to analyze the effect of the proppant wettability on the flow efficiencies of oil and water under different conditions (for example, various proppant size, water saturation, and waterflooding). Also, it was required to determine the optimal wettability of proppants in the available candidates for the enhancement of oil recovery in the hydraulic fracturing process. Results of the work indicate that the proppant wettability plays an essential role in the productivities of water and oil in tight sandstones. Compared with the same‐size oil‐wet proppants, the mixed‐wet proppants contribute to increasing the oil flow efficiency and reducing the produced volume of water. However, an increased value of proppant size can significantly enhance the oil recovery. Besides, using the oil‐wet proppants, the waterflooding phenomenon can lead to a lower oil recovery than that of the non‐water‐flooded specimen. Based on the findings of the microscopic structural characteristics of the proppant surface, a fluid channel mechanism was proposed to help understand the proppant wettability effect on the flow behaviors of oil and water. This research can provide guidance on the determination of proppants in the designs of hydraulic fracturing operations. These findings can help the reservoir engineers dealing with hydraulic fracturing better design the surface wettability of the proppants, especially for those reservoirs with a multi‐phase flow.
An Abundant and Renewable Potential Energy Source: Harvestable Energy under Vehicle Wheels
Authors: Li Feng‐Chen
Published: February 2019

Approaches for energy harvesting from rotating vehicle tires have been investigated for years; however, where the harvestable energy is actually generated has not been discussed so far. For the first time, the potentially harvestable energy under vehicle wheels, as a real energy source, is discovered. Estimations show that the global potentially harvestable energy from the vehicle wheels could be 3.26 × 1011 kW, equivalent to 14 500 times the installed capacity of the worldwide largest hydraulic power plant, Three Gorges Dam of China; 36.7% saving of a vehicle's fuel consumption could be achieved if this potential energy could be totally harvested. State‐of‐the‐art energy harvesting techniques can only extract a negligibly small amount of the energy under vehicle wheels, calling for revolutionary new energy harvesting techniques.
Comorbidity of reading disabilities and ADHD: Structural and functional brain characteristics
Authors: Langer Nicolas , Benjamin Christopher , Becker Bryce L. C. , Gaab Nadine
Published: February 2019

Reading disabilities (RD) and attention‐deficit/hyperactivity disorder (ADHD) are two of the most common developmental disorders. RD and ADHD frequently co‐occur, which raises questions about how the disorders interact and to what extent they can be differentiated. To date, the underlying neural mechanisms leading to RD–ADHD comorbidity (COM) are not understood. In this study, structural and functional magnetic resonance imaging (fMRI) were combined with comprehensive behavioral testing in order to characterize the behavior, brain structure, and neural correlates of executive function, phonological processing and reading fluency in 60 children with clinical diagnoses of RD, ADHD, or COM, and controls. Whole‐brain analyses of variance were performed on cortical thickness values and on the data of the three fMRI tasks to investigate overall group differences. To validate these findings, a region of interest analysis was performed in regions that have previously been shown to exhibit group differences in children with RD or ADHD using the same paradigms. The neuroimaging results demonstrated structural and functional atypicalities for COM in regions that are frequently associated with deficits in children with isolated ADHD or RD. A combination of shared and distinctive brain alterations between the clinical groups was identified, supporting the multiple deficit model for ADHD, RD, and its comorbidity.