bluuebunny/crossref_metadata_2025 huggingface dataset:
Photobiomodulation by diffusing optical fiber on spinal cord: A feasibility study in piglet model
Authors: Liang Zhuowen , Lei Tao , Wang Shuang , Zuo Xiaoshuang , Li Kun , Song Jiwei , Sun Jiakai , Zhang Jiawei , Zheng Qiao , Kang Xiaowei , Ma Yangguang , Hu Xueyu , Ding Tan , Wang Zhe
Published: October 2019

Previous studies on spinal cord injury (SCI) have confirmed that percutaneous photobiomodulation (PBM) therapy can ameliorate immunoinflammatory responses at sites of injury, accelerate nerve regeneration, suppress glial scar formation and promote the subsequent recovery of locomotor function. The current study was performed to evaluate a large‐animal model employing implanted optical fibers to accurately irradiate targeted spinal segments. The method's feasibility and irradiation parameters that do not cause phototoxic reaction were determined, and the methodology of irradiating the spinal cord with near‐infrared light was investigated in detail. A diffusing optical fiber was implanted above the T9 spinal cord of Bama miniature pigs and used to transfer near‐infrared light (810 nm) onto the spinal cord surface. After daily irradiation with 200, 300, 500 or 1000 mW for 14 days, both sides of the irradiated area of the spinal cord were assessed for temperature changes. The condition of the spinal cord and the position of optical fiber were investigated by magnetic resonance imaging (MRI), and different parameters indicating temperature increases or phototoxicity were measured on the normal spinal cord surface due to light irradiation (ie, heat shock responses, inflammatory reactions and neuronal apoptosis), and the animals' lower‐limb neurological function and gait were assessed during the irradiation process. The implanted device was stable inside the freely moving animals, and light energy could be directly projected onto the spinal cord surface. The screening of different irradiation parameters preliminary showed that direct irradiation onto the spinal cord surface at 200 and 300 mW did not significantly increase the temperature, stress responses, inflammatory reactions and neural apoptosis, whereas irradiation at 500 mW slightly increased these parameters, and irradiation at 1000 mW induced a significant temperature increase, heat shock, inflammation and apoptosis responses. HE staining of spinal cord tissue sections did not reveal any significant structural changes of the tissues compared to the control group, and the neurological function and gait of all irradiated animals were normal. In this study, we established an in‐vivo optical fiber implantation method, which might be safe and stable and could be used to directly project light energy onto the spinal cord surface. This study might provide a new perspective for clinical applications of PBM in acute SCI.
Exploring the White and male culture: Investigating individual perspectives of equity and privilege in engineering education
Authors: Eastman Michael G. , Miles Monica L. , Yerrick Randy
Published: October 2019

Background

Engineering education in the United States has been accused of favoring White men at the exclusion of those traditionally underrepresented in engineering. However, contrary to the culturally responsive literature addressing approaches to “colorblindness,” engineering faculty believe they should treat all students equally.

Purpose

This study explored conceptions of equity and privilege present within the culture of engineering education, particularly the White male population.

Method

This longitudinal qualitative study investigated the experiences of one longtime engineering professor, an insider to the culture of engineering confronted with conceptions of his own privilege. We analyzed interview, focus group, and field note data to evaluate shifts in our participant's perspective while he was enrolled in a doctoral program that challenged his views of race, privilege, and equity.

Results

Our participant was initially opposed to conceptions of his own privilege. Through repeated challenges to his beliefs about privilege coupled with reflections on his experiences and positioning in society, his beliefs shifted toward recognizing inequities based on class and race.

Conclusions

In a discipline with an overrepresentation of White men, there can be resistance to addressing topics of equity and privilege. However, it is possible for engineering educators, despite their race and gender, to change their beliefs related to the culture of engineering education and to address inequities within engineering departments and classrooms.
Test–Retest Reliability of the Brain Metabolites GABA and Glx With JPRESS, PRESS, and MEGA‐PRESS MRS Sequences in vivo at 3T
Authors: Baeshen Arwa , Wyss Patrik O. , Henning Anke , O'Gorman Ruth L. , Piccirelli Marco , Kollias Spyridon , Michels Lars
Published: October 2019

Background

The optimization of magnetic resonance spectroscopy (MRS) sequences allows improved diagnosis and prognosis of neurological and psychological disorders. Thus, to assess the test–retest and intersequence reliability of such MRS sequences in quantifying metabolite concentrations is of clinical relevance.

Purpose

To evaluate the test–retest and intersequence reliability of three MRS sequences to estimate GABA and Glx = Glutamine+Glutamate concentrations in the human brain.

Study Type

Prospective.

Subjects

Eighteen healthy participants were scanned twice (range: 1 day to 1 week between the two sessions) with identical protocols.

Field Strength/Sequence

3T using a 32‐channel SENSE head coil in the PCC region; PRESS, JPRESS, and MEGA‐PRESS sequences.

Assessment

Metabolite concentrations were estimated using LCModel (for PRESS and MEGA‐PRESS) and ProFit2 (for JPRESS).

Statistical Tests

The test–retest reliability was evaluated by Wilcoxon signed‐rank tests, Pearson's r correlation coefficients, intraclass‐correlation coefficients (ICC), coefficients of variation (CV), and by Bland–Altman (BA) plots. The intersequence reliability was assessed with Wilcoxon signed‐rank tests, Pearson's r correlation coefficients, and BA plots.

Results

For GABA, only the MEGA‐PRESS sequence showed a moderate test–retest correlation (r = 0.54, ICC = 0.5, CV = 8.8%) and the BA plots indicated good agreement (P > 0.05) for all sequences. JPRESS provided less precise results and PRESS was insensitive to GABA. For Glx, the r and ICC values for PRESS (r = 0.87, ICC = 0.9, CV = 2.9%) and MEGA‐PRESS (r = 0.70, ICC = 0.7, CV = 5.3%) reflect higher correlations, compared with JPRESS (r = 0.39, ICC = 0.4, CV = 20.1%).

Data Conclusion

MEGA‐PRESS and JPRESS are suitable for the reliable detection of GABA, the first being more precise. The three sequences included in the study can measure Glx concentrations.

Level of Evidence: 2

Technical Efficacy: Stage 1

J. Magn. Reson. Imaging 2020;51:1181–1191.
The mechanism of freeze‐thawing induced accumulation of γ‐aminobutyric acid in germinated soybean
Authors: Yang Runqiang , Hui Qianru , Feng Xiaoyun , Feng Li , Gu Zhenxin , Wang Pei
Published: October 2019

BACKGROUND

γ‐Aminobutyric acid (GABA) is a non‐protein amino acid with several functions in the human body. Although freeze‐thawing could effectively accumulate GABA in soybean sprouts, the mechanism has not been revealed. The mechanism by which freeze‐thawing enhances GABA accumulation in germinated soybean was revealed by evaluating GABA content, the activity of related synthesis enzymes, and the microstructure of the tissues and cells of sprouts. The germinated soybeans were treated at different temperatures (from −196 °C to 25 °C) for 12 h and then thawed at 25 °C for 6 h.

RESULTS

The results showed that GABA content in frozen soybean sprouts did not change significantly before thawing. After thawing, the GABA content of sprouts increased by 83.9% and 82.9% when treated by liquid nitrogen flash freeze at − 80 °C for 12 h compared with the control (4 °C treatment for 12 h). The results indicated that GABA formation mainly occurred during thawing. However, glutamate decarboxylase (GAD), diamine oxidase (DAO), and aminoaldehyde dehydrogenase (AMADH) activity decreased during thawing. Based on the malonaldehyde (MDA) content and microstructure of sprouts, it was suggested that freezing at lower temperatures (< −20 °C) maintained the integrity of the cell structure, while the tissues and cell membranes were broken during thawing.

CONCLUSION

These results could provide evidence for the hypothesis that GABA formation resulted from full contact between enzymes and substrates during thawing, rather than the contribution of higher enzyme activity. © 2019 Society of Chemical Industry
Mycotoxins feed contamination in a dairy farm – potential implications for milk contamination and workers' exposure in a One Health approach
Authors: Viegas Susana , Assunção Ricardo , Twarużek Magdalena , Kosicki Robert , Grajewski Jan , Viegas Carla
Published: October 2019

Background

Dairy farming feed can be contaminated with mycotoxins, affecting animals' health and milk quality. Dairy farming is also prone to occupational exposure to mycotoxins, and feed is recognized as a source of contamination in the workplace. An exploratory study was developed in a dairy farm located in Portugal intending to assess the mycotoxins present in the feed.

Results

All the samples analyzed presented contamination by at least two mycotoxins and up to a maximum of 13 mycotoxins in the same sample. Zearalenone (ZEA) was detected in all the samples (n = 10) followed by deoxynivalenol (DON), which was reported in eight samples, and ochratoxin A (OTA), reported in five samples.

Conclusion

The results point to the possible contamination of milk by several mycotoxins and raise the possibility of occupational exposure to mycotoxins due to feed contamination. An adequate One Health approach for dairy production should address these issues through effective preventive actions such as avoiding the use of feed contaminated with mycotoxins. This represents an important challenge due to climate change. It requires proper attention and accurate management measures. © 2019 Society of Chemical Industry
Humic acid functionalized hyperbranched polytriazine based dispersive solid‐phase extraction for acaricides determination in tea matrix
Authors: Mi Yiduo , Cui Xiaoyan , Jia Chendi , Liu Xinya , Zhang Sanbing , Zhou Wenfeng , Gao Haixiang , Lu Runhua
Published: October 2019

Hyperbranched polytriazine functionalized with humic acid was prepared and developed as new sorbents for dispersive solid‐phase extraction of three acaricides (clofentezine, fenpyroximate, and pyridaben) in tea samples combined with high‐performance liquid chromatography detection. The sorbents were characterized by scanning electron microscopy, energy dispersive spectroscopy, Zeta‐potential, and Fourier transform infrared spectroscopy. The extraction parameters (extraction time, ionic strength, desorption conditions) were optimized. The adsorption mechanism was evaluated utilizing Fourier transform infrared spectra. Under optimum conditions, satisfactory analytical performances were achieved, which included high precision (1.33–9.62%), low limits of detection (0.19–3.54 µg/L), and wide linear range (2.5–500 µg/L) for the analysis of the acaricides. Moreover, the proposed method proved highly effective for the determination of acaricides in tea samples, with the relative recoveries in the range of 65.20–108.13% and relative standard deviations < 9.87%. The method has great application potential for the detection of acaricides in tea samples.
Association of cyclophilin A level and pulse pressure in predicting recurrence of cerebral infarction
Authors: Chang Chen‐Shu , Kuo Chen‐Ling , Huang Ching‐Shan , Cheng Yu‐Shan , Lin Song‐Shei , Liu Chin‐San
Published: October 2019

Cyclophilin A (CypA), secreted from vascular smooth muscle cells and inflammatory cells in response to oxidative stress, promotes vascular atherosclerosis and development of carotid stenosis. Increased concentration of plasma CypA in acute cerebral infarction was demonstrated clinically. The primary aim of this study was to investigate the prognostic impact between CypA level and outcome in patients with acute ischemic stroke. Admission serum CypA concentrations were detected in 66 acute cerebral infarction patients and in 52 healthy individuals. Inflammatory biomarkers, including high‐sensitivity C‐reactive protein, adhesion molecules, interleukins, and matrix‐metalloproteases, were also assessed. We also examined the relationship between plasma biomarkers, blood pressure (BP), pulse pressure, the carotid artery velocity, the prognostic assessment with modified Rankin scale, and stroke recurrence. Plasma CypA concentration was higher on the first day of hospitalization in the high BP stroke group than in normal BP stroke group, which was statistically significant, which was observed even in the third month and sixth month follow‐up outpatient periods. For stroke recurrence prediction, there was an important association between the higher (>60) pulse pressure on the seventh day of hospitalization and CypA level on the third month and sixth month follow‐up outpatient periods. Our study revealed higher circulating serum levels of CypA in the hypertensive stroke group than in the non‐hypertensive stroke group. We expect that elevated plasma CypA level and raised pulse pressure during hospitalization to become valuable biomarkers in predicting stroke recurrence in the sixth month assessment of acute cerebral infarction.
Surveillance endoscopy after tracheostomy placement in children: Findings and interventions
Authors: Liu C. Carrie , Soares Jennifer J. , Elder Leslie , Hill Leslee , Abts Matthew , Bonilla‐Velez Juliana , Dahl John P. , Johnson Kaalan E. , Ong Thida , Striegl Amanda M. , Whitlock Kathryn , Parikh Sanjay R.
Published: October 2019

Objectives/Hypothesis

The Seattle Children's Hospital implemented the Trach Safe Initiative to improve airway safety in tracheostomy‐dependent children (TDC). A key tenet of this initiative is surveillance endoscopy. The objectives of this study were to describe the prevalence of abnormal airway changes in TDC, identify risk factors for these changes, and describe the frequency of airway interventions.

Study Design

Retrospective case series.

Methods

This is a review of children 0 to 21 years old who underwent tracheostomy and surveillance endoscopy from February 1, 2014 to January 1, 2019. Descriptive statistics were used to report the prevalence of abnormal airway changes and interventions following tracheostomy. Pearson χ2 tests and logistic regression were used to identify risk factors for the development of abnormal changes.

Results

There were 127 children identified. The median time from tracheostomy to initial surveillance endoscopy was 1.6 months (interquartile range = 1.3–2.4 months). At initial endoscopy, 86.6% of patients had at least one abnormal airway finding. The most common findings were subglottic edema/stenosis (57.3%), glottic edema (37.3%), and suprastomal granulation tissue (31.8%). Prematurity and a history of failed extubations were significantly associated with abnormal findings on endoscopy (odds ratio [OR] = 7.2, P = .01 and OR = 4.1, P = .03, respectively). Of those with abnormal findings, 32.7% underwent an intervention to improve airway patency and safety. The most common interventions performed were suprastomal granuloma excision (44.4%), steroid injection (22.2%), and balloon dilation of the glottis or subglottis (19.4%).

Conclusions

The prevalence of early abnormal airway changes in TDC is high, particularly in young children with a history of prematurity and failed extubation.

Level of Evidence

4

Laryngoscope, 130:1327–1332, 2020
The Making of Infinity Cube, a Bioluminescence Art Exhibit
Authors: Latz Michael I.
Published: October 2019

Inspired by a midnight stroll on a beach in Mexico, it culminated in an innovative installation at the Birch Aquarium at Scripps Institution of Oceanography. This is the story of a bioluminescence art exhibit called Infinity Cube, which was on display from April 2017 through September 2018.
Putting an end to the Pseudomonas aeruginosa IQS controversy
Authors: Cornelis Pierre
Published: October 2019

Despite published evidence that IQS (2‐(2‐hydroxylphenyl)‐thiazole‐4‐carbaldehyde) is in fact aeruginaldehyde, a by‐product of the siderophore pyochelin biosynthesis or degradation and that the ambABCDE genes are not responsible for IQS synthesis, several authors, including in top review journals, perpetuate the wrong information. I hope that this short comment will clarify the situation once and for all.
Development of upper air simulator for the calibration of solar radiation effects on radiosonde temperature sensors
Authors: Lee Sang‐Wook , Yang Inseok , Choi Byung IL , Kim Sunghun , Woo Sang‐Bong , Kang Woong , Oh Youn Kyun , Park Seongchong , Yoo Jae‐Keun , Kim Jong Chul , Lee Young Hee , Kim Yong‐Gyoo
Published: October 2019

For the accurate measurement of temperature in the upper air by using radiosondes, one prerequisite is the compensation of solar radiation effects that cause sensor heating. The development at the Korea Research Institute of Standards and Science (KRISS) of an upper air simulator (UAS) that can simulate radiation effects is reported. The UAS can independently control four environmental parameters: irradiance, temperature, pressure and air speed. An entire radiosonde can be installed in the test chamber and the measurement data transmitted remotely via an antenna. Solar irradiance is mimicked by using a solar simulator that irradiates the radiosonde sensor. The temperature of the test chamber is controlled from −70 to 20°C by placing it inside a climatic chamber. The pressure and ventilation speed in the test chamber are modulated using combinations of sonic nozzles, a mass flow controller and a vacuum pump. A ventilation speed of 5 m·s−1, which mimics the speed of ascent of the radiosondes when lifted using a balloon, is achieved at pressures as low as 7 hPa. The capability of controlling the environmental parameters independently and the stability of each parameter are presented. As a proof of concept, the radiation‐induced bias on the temperature sensor of a commercial radiosonde Vaisala RS41 is measured. The effect of each parameter is investigated by varying it while keeping the other parameters fixed. Radiosonde calibration using the UAS at the KRISS will help improve the traceability of upper air measurements to the International System of Units.
On the time‐fractional Keller‐Segel model for chemotaxis
Authors: Cuevas Claudio , Silva Clessius , Soto Herme
Published: October 2019

We consider the time‐fractional Keller‐Segel system of order α∈(0,1). Interesting properties of solutions are highlighted, like regularity and large time behavior in Lebesgue spaces, which depend on the fractional exponent α.
Probabilistic surrogate models for uncertainty analysis: Dimension reduction‐based polynomial chaos expansion
Authors: Son Jeongeun , Du Yuncheng
Published: October 2019

This paper presents an approach for efficient uncertainty analysis (UA) using an intrusive generalized polynomial chaos (gPC) expansion. The key step of the gPC‐based uncertainty quantification (UQ) is the stochastic Galerkin (SG) projection, which can convert a stochastic model into a set of coupled deterministic models. The SG projection generally yields a high‐dimensional integration problem with respect to the number of random variables used to describe the parametric uncertainties in a model. However, when the number of uncertainties is large and when the governing equation of the system is highly nonlinear, the SG approach‐based gPC can be challenging to derive explicit expressions for the gPC coefficients because of the low convergence in the SG projection. To tackle this challenge, we propose to use a bivariate dimension reduction method (BiDRM) in this work to approximate a high‐dimensional integral in SG projection with a few one‐ and two‐dimensional integrations. The efficiency of the proposed method is demonstrated with three different examples, including chemical reactions and cell signaling. As compared to other UA methods, such as the Monte Carlo simulations and nonintrusive stochastic collocation (SC), the proposed method shows its superior performance in terms of computational efficiency and UA accuracy.
A 3D Lagrangian gradient smoothing method framework with an adaptable gradient smoothing domain‐constructing algorithm for simulating large deformation free surface flows
Authors: Mao Zirui , Liu G. R.
Published: October 2019

A novel smoothing particle hydrodynamics (SPH)‐like Lagrangian meshfree method, named as Lagrangian gradient smoothing method (L‐GSM), has been proposed to avoid the “tensile instability” issue in SPH simulation by replacing the SPH particle‐summation gradient approximation technique with a local grid‐based GSM gradient smoothing operator. The L‐GSM model has been proven effective and efficient when applied to a wide range of large deformation problems for fluids and flowing solids in two‐dimensional case. In this study, a three‐dimensional (3D) L‐GSM numerical framework is proposed for simulating large deformation problems with the existence of free surfaces through developing a widely adaptable 3D gradient smoothing domain (GSD) constructing algorithm. It includes three key novel ingredients: (i) the localized GSD based on an efficient distance‐oriented particle‐searching algorithm enabling both easy implementation and efficient computation; (ii) a novel algorithm for constructing 3D GSD to guarantee the effectiveness of the 3D GSM gradient operator adaptable to any extreme cases; (iii) a robust normalized 3D GSM gradient operator formulation that can restore the accuracy of gradient approximation even on boundary interface. The effectiveness of the proposed 3D GSD‐constructing algorithm is first verified under various distribution conditions of particles. The accuracy of the proposed adaptable 3D GSM gradient algorithm is then examined through conducting a series of numerical experiments with different spacing ratios. Finally, the 3D L‐GSM numerical framework is applied to solve a practical problem of free surface flows with large deformation: collapse of a soil column. The results reveal that the present adaptable 3D L‐GSM numerical framework can effectively handle the large deformation problems, like flowing solids, with a constantly changing arbitrary free surface profile.
Synergetic effect of thermal conductivity and flame retardancy of cyanate ester composites containing DOPO and BN with great dielectric properties
Authors: Yao Lulu , Wang Jun , Chen Xi , Lu Meijuan
Published: October 2019

DOPO and boron nitride (BN) fillers with different particle sizes and several loadings were employed to improve the properties of cyanate ester (CE) resin. The effects of BN content and particle size on the thermal conductivity of the BN‐DOPO/CE ternary composites were discussed. The influence of enhancing the thermal conductivity of the ternary composites on their flame retardancy was studied. The consequences showed that increasing the thermal conductivity of BN‐DOPO/CE composites had an active impact on their flame retardancy. Approving flame retardancy of the ternary composites was certified by the high limiting oxygen index (LOI), UL‐94 rating of V‐0, and low heat release rate (HRR) and total heat release (THR). For instance, in contrast with pure CE matrix, peak of HRR (pk‐HRR), average of HRR (av‐HRR), THR, and average of effective heat of combustion (av‐EHC) of CEP/BN0.5 μm/10 composite were decreased by 51.7%, 33.8%, 18.7%, and 18.9%, respectively. Thermal gravimetry analysis (TGA) showed that the addition of BN fillers improves the thermal stability of the composites. Moreover, the ternary composites possess good dielectric properties. Their dielectric constants (ε) are less than 3, and dielectric loss tangent (tgδ) values are lower than neat CE resin.
A Citrulline‐Based Translational Population System Toxicology Model for Gastrointestinal‐Related Adverse Events Associated With Anticancer Treatments
Authors: Yoneyama Tomoki , Abdul‐Hadi Kojo , Brown Adam , Guan Emily , Wagoner Matt , Zhu Andy Z.X.
Published: October 2019

Gastrointestinal (GI)‐related adverse events (AEs) are commonly observed in the clinic during cancer treatments. Citrulline is a potentially translatable biomarker of GI AEs. In this study, irinotecan‐induced citrulline changes were studied for a range of doses and schedules in rats. A translational system toxicology model for GI AEs using citrulline was then developed based on new experimental data and parameters from a literature intestinal cell dynamic model. With the addition of feedback‐development and tolerance‐development mechanisms, the model well captured the plasma citrulline profiles after irinotecan treatment in rats. Subsequently, the model was translated to humans and predicted the observed GI AE dynamics in humans including dose‐scheduling effect using the cytotoxic and feedback parameters estimated in rats with slight calibrations. This translational toxicology model could be used for other antineoplastic drugs to simulate various clinical dosing scenarios before human studies and mitigate potential GI AEs.
Design of AlGaN/AlN Dot‐in‐a‐Wire Heterostructures for Electron‐Pumped UV Emitters
Authors: Dimkou Ioanna , Harikumar Anjali , Ajay Akhil , Donatini Fabrice , Bellet-Amalric Edith , Grenier Adeline , den Hertog Martien I. , Purcell Stephen T. , Monroy Eva
Published: October 2019

This article describes the fabrication of nitrogen‐polar AlxGa1−xN/AlN (x = 0, 0.1) quantum dot (QD) superlattices (SLs) integrated along GaN nanowires (NWs) for application in electron‐pumped UV sources. The NWs are grown using plasma‐assisted molecular beam epitaxy on n‐type Si(111) wafers using a low‐temperature AlN nucleation layer. Growth conditions are tuned to obtain a high density of noncoalesced NWs. To improve the uniformity of the height along the substrate, the growth begins with a long (≈900 nm) NW base, with a diameter of 30–50 nm. The AlxGa1−xN/AlN active region is 400 nm long (88 periods of QDs), long enough to collect the electron–hole pairs generated by an electron beam with an acceleration voltage ≤5 kV. The spectral response is tuned in the 340–258 nm range by varying the dot/barrier thickness ratio and the Al content in the dots. Internal quantum efficiencies as high as 63% are demonstrated.
Controllable Delay and Polarization Routing of Single Photons
Authors: Maisch Julian , Vural Hüseyin , Jetter Michael , Michler Peter , Gerhardt Ilja , Portalupi Simone Luca
Published: October 2019

Full control of single photons is important in quantum information and quantum networking. In particular, controlling the photon–atom interaction can be an appealing means to realize more complex quantum experiments. As a matter of example, the storage of photons into atomic media represents one key approach to memory‐assisted quantum communication and computing. Here it is shown that the propagation of single photons from a semiconductor quantum dot can be deliberately controlled by an atomic vapor under the application of an external magnetic field. The present results enable the use of an atomic vapor as a precise and reliable wavelength selective delay and allows for routing the single photons according to their polarization and the external magnetic field. With an overall delay of 25 ns, it is possible to fine‐tune the arrival time of the photons by more than 600 ps which matches the scale of the quantum dot's lifetime. The experimental data are fully reproduced by a theoretical model.
3D‐Enhanced, High‐Performing, Super‐hydrophobic and Electromagnetic‐Interference Shielding Fabrics Based on Silver Paint and Their Use in Antibacterial Applications
Authors: Ghosh Sabyasachi , Das Poushali , Ganguly Sayan , Remanan Sanjay , Das Tushar Kanti , Bhattacharyya Swarup Krishna , Baral Joydeep , Das Amit Kumar , Laha Tapas , Das Narayan Ch.
Published: October 2019

A unique brush coating technique was adopted to prepare high microwave absorbing super‐hydrophobic bactericidal fabrics. 3D micro‐CT, field emission scanning electron microscopy (FE‐SEM) and high resolution transmission electron microscopy (HR‐TEM) analyses were employed to establish the composite morphology. X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the embedded silver nanoparticles in the cotton fabrics. The developed thin wearable coated fabrics hold the lowest resistivity of 8 ohm‐cm−2 (lighten up series of LEDs) and electromagnetic interference (EMI) shielding effectiveness (SE) of 30.07 dB at 0.3 mm coating thickness within the X‐band frequency range. These thin coated fabrics can be the used in the flexible electronic devices along with extreme bactericidal feature against E. coli.
Byproduct‐Free Synthesis, Characterization, and Reactivity of 1, 2‐Diaminosiloxane Monolayers on Silicon/Silicon Dioxide
Authors: Khadka Kiran , Carpenter George Kenyon , Ferguson Gregory S.
Published: October 2019

The facile self‐assembly of monolayers films derived from N‐(2‐aminoethyl)‐2, 2, 4‐trimethyl‐1‐aza‐2‐silacyclopentane on silicon/silicon dioxide substrates from the solution phase is reported. This adsorbate reacts with silanols at the surface to produce a covalent siloxane linkage to the substrate via ring‐opening and produces no byproduct(s). The resulting diamine surface reacts with maleic anhydride or succinic anhydride to produce the corresponding carboxylic‐acid terminated surfaces. The kinetics of these reactions and their products were characterized by contact‐angle goniometry, optical ellipsometry, and X‐ray photoelectron spectroscopy.
Ultrathin Graphitic Carbon Nitride Nanosheets as Efficient Catalysts for Degradation of Pollutants under Visible Light
Authors: Zhao Qian , Yang Cheng , Liu Ruifeng
Published: October 2019

In this paper, ultrathin g‐C3N4 nanosheets (U‐CNs‐4) were prepared via short time sonication‐assisted exfoliation and solvothermal treatment method in ethylene glycol solvent. It was found that the obtained ultrathin g‐C3N4 nanosheets with a thickness of ranges from 4 to 5 nm, exhibited a higher specific surface area of 35.7 m2/g and larger electronic band structure (by 0.16 eV), enhanced photocurrent response and improved electron transport ability due to the quantum confinement effect. The photocatalytic activities have been proved by photocatalytic degradation Rhodamine B (RhB) and ciprofloxacin (CIP) under visible‐light irradiation. Results show that the U‐CNs‐4 exhibited obviously enhanced photocatalytic activity in comparison with other samples. The degradation efficiency of RhB was 4.4 times higher than that of the bulk g‐C3N4 (B‐CN). The enhanced photocatalytic activity was due to the more active sites, the enhanced oxidation ability and improved electron transport ability, which improving separation efficiency of photogenerated electron‐hole pairs. Finally, the possible for the enhancing photocatalytic mechanism was revealed based on the active species trapping and electron spin resonance (ESR) experiments.
Folic‐Acid‐Functionalized Magnetic Nanoparticles as Green and Magnetic Recyclable Catalyst for the Synthesis of 4‐Aryl‐NH‐1,2,3‐triazoles in a Green Media
Authors: Bagheri Sepideh , Nejad Masoumeh Jadidi , Pazoki Farzane , Miraki Maryam Kazemi , Heydari Akbar
Published: October 2019

A useful, robust, and cheap procedure was obtained for the synthesis of 4‐aryl‐NH‐1,2,3‐triazoles via aromatic aldehydes, nitromethane and choline azide in the presence of folic acid immobilized magnetic nanoparticle with good yields. The magnetic catalyst is easily synthesized and can be recycled at least five times with no significant loss in activity. In addition, the choline azide is used as a reagent and green solvent.
Synthesis of Bis‐(2‐thiazolyl)amine Analogues and Evaluation of Their Antibacterial, Antioxidant and Cytotoxic Activities
Authors: Alaraidh Ibrahim A. , Okla Mohammad K. , Alamri Saudi A. , AL‐ghamdi Abdullah A. , Soufan Walid H. , Allam Ahmed A. , Fouda Moustafa M. G. , Gaffer Hatem E.
Published: October 2019

An effective and economical preparation of bis‐(2‐thiazolyl)amine analogues was achieved by the reaction of 3‐(5‐arylazothiazol‐2‐yl)thioureas with various halogenated carbonyl reagents (namely; chloroacetic acid, diethyl bromomalonate, chloroacetone and phenacyl bromide). The physical and spectral analyses were performed to demonstrate the correct configurations of all incorporated analogues. It is clear that most of synthesized bis‐(2‐thiazolyl)amine derivatives revealed good biological efficacy, including anticancer, antibacterial and antioxidant. The synthesized bis‐(2‐thiazolyl)amine derivatives were investigated as cytotoxic agents against four different cell lines, in which the results revealed potent efficacies of the synthesized derivatives relative to the results of antibiotic standards. In addition, the antioxidant efficacy of all analogues was determined using ABTS•+ “2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid” method.
Thermal Conversion Behavior of Medium–Low–Temperature Coal Tar Pitch During Liquid–Phase Carbonization Process
Authors: Zhu Yaming , Hu Chaoshuai , Zhao Chunlei , Xu Yunliang , Gao Lijuan , Zhao Xuefei
Published: October 2019

Medium–low temperature coal tar pitch (MLP) is a type of aromatic carbonaceous material obtained by the low temperature distillation of low rank coal, and is considered as a desirable raw material for the production of artificial carbon/graphite material. The thermal conversion behaviors of MLP during the liquid‐phase carbonization process were analyzed in detail in this study. Further, the changes of molecular structure and carbon microcrystalline structure of MLP and liquid‐phase carbonization products derived from it were quantitatively investigated by optical microscopy, fourier transform infrared spectroscopy, Raman spectroscopy, X‐ray diffraction, and curve‐fitting method. Results showed that both branched chain and the contents of C=O functional groups in the MLP played a key role in the reaction reactivity. Moreover, temperature of 450 °C was found to be a rapid changing temperature point on the enhancement of thermal conversion of MLP. The stacking height (Lc), parallel layers (N), average number of aromatic rings in each layer (n), ratio of ‘impurity’ structure (RI), ratio of amorphous carbon structure (RAC), ratio of graphite carbon structure (RGC), and ratio of defects graphite carbon structure (RDGC) exhibited a significant change with the improvement of liquid‐phase carbonization temperature.
Preparation of DABCO‐Based Acidic‐Ionic‐Liquid‐Supported ZnO Nanoparticles and Their Application for Ecofriendly Synthesis of N‐Aryl Polyhydroquinoline Derivatives
Authors: Mondal Priya , Chatterjee Sauvik , Sarkar Piyali , Bhaumik Asim , Mukhopadhyay Chhanda
Published: October 2019

Here we have reported a new significant DABCO based acidic ionic liquid ([DABCO(C2COOH)2]2+[Br−]2). With the assistance of this IL, ZnO nanoparticle (NP) supported [DABCO (C2COOH)2]2+[Br−]2 immobilised ZnO‐[DABCO(C2COOH)2]2+[Br−]2 was established, a new supported Catalyst with an ionic liquid layer (SCILL,). Since ZnO nanoparticles are amphoteric in nature and DABCO based ionic liquid is acidic in nature, it posses both acidic and basic catalytic site in a single moiety. With the assistance of this quasi heterogeneous, efficient, recyclable catalyst we were able to produce series of N‐aryl hexahydroquinolines in aqueous medium with good to excellent yield within shorter reaction time. This catalyst was characterised by Scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscope (HRTEM), Energy Dispersive Analysis X‐ray (EDAX), Dynamic Light Scattering Spectroscopy (DLS), Powder X‐Ray Diffraction (PXRD), Thermo Gravimetric Analysis (TGA) and Fourier Transform Infrared spectroscopy (FT‐IR). Here, synergetic catalytic effect of amphoteric heterogeneous zinc oxide nanoparticles and acidic homogeneous DABCO based ionic liquid were commendably compiled.
Cadmium(II)‐Loaded Fe3O4@MPTS Nanoparticles: Preparation and Application as Catalyst for C‐N Coupling Reactions
Authors: Rathod Prakash B. , Chappa Sankararao , Kumar K. S. Ajish , Pandey Ashok K. , Athawale Anjali A.
Published: October 2019

Surface of Fe3O4 nanoparticles (NPs) was coated with (3‐mercaptopropyl)trimethoxysilane (MPTS) to form Fe3O4@MPTS NPs. Thus formed Fe3O4@MPTS NPs were studied for preconcentration of the representative Cd(II), Pb(II), and As(III) ions, and loading capacities toward these ions were found to be 17(±0.7), 29(±0.3), and 13(±0.5) mg g−1, respectively. As an example of safe utilization of toxic metal ions strongly bonded on magnetically retrievable NPs for catalytic applications, the Cd(II) loaded Fe3O4@MPTS NPs were successfully utilized for conducting the C−N bond formation reaction in comparable yields with that were reported in the literature but exhibited higher turnover number and turnover frequency.
Gold‐Catalyzed Reaction of 2H‐Tetrazoles with Alkynes: Efficient Route to N‐Alkenylated Tetrazoles
Authors: Cao Ziping , Zhao Changyin , Zhu Jiekun , Yan Shikun , Tian Laijin , Sun Xuejun , Meng Xin
Published: October 2019

A gold‐catalyzed reaction of 2H‐tetrazoles with alkynes was described for the efficient synthesis of a variety of N‐alkenylated tetrazole derivatives, including N‐1 and N‐2 vinyl functionalized products which are readily isolated by column chromatography. The reaction mechanism was proposed to be a nucleophilic addition process to the alkyne motif activated by gold catalyst. The reaction features mild reaction condition, simple operation and high yields.
Comparison of Machine Learning Algorithms in Screening Potential Additives to Ni/Al2O3 Methanation Catalysts for Improving the Anti‐Coking Performance
Authors: Han Xiaoxia , Yue Lin , Zhao Chaofan , Jiang Shaohua , Liu Junjie , Li Yuting , Ren Jun
Published: October 2019

In this paper, the 16 physicochemical properties of 56 elements were processed through principal component analysis (PCA) transformation and Gaussian mixture model clustering. And then, a pool of eleven representative elements was chosen for subsequent experiments on resistance to carbon deposition. Based on the experimental results and the principal components of the selected elements, radial basis function network (RBFN), support vector machine (SVM) and Gaussian process regression (GPR) models were constructed, respectively. Compared with other models, the prediction results of GPR model are more accurate. It predicted that W element is the most effective additive, which was confirmed by further experiments. To our knowledge, this finding has not yet been formally reported in the literature. The application and implementation of this strategy provides new ideas for high dimensional, small sample and nonlinear catalyst data modeling.
Catalyst‐Free and Selective Ring Openings of N‐Tosylaziridines: Good Approaches to β‐Amino Sulfones, β‐Bis(amino)thioethers, 1,2‐Azide Amines and 1,2‐Diamines
Authors: Li Xing , Zheng Leijie , Li Nana , Chang Honghong , Gao Wenchao , Wei Wenlong , Chen Wenwen
Published: October 2019

Four kinds of catalyst‐free and highly selective C−N bond functionalizations have been achieved through ring openings of N‐tosylaziridines with sodium sulfonates, sodium sulfide, sodium azide and amines, respectively. DMF was found to be a highly efficient solvent to afford the corresponding β‐amino sulfones, β‐bis(amino)thioethers, 1,2‐azide amines and 1,2‐diamines in the absence of any catalyst with good to excellent yields and good regioselectivity.
Electroacoustic Quantification of Surface Bound Ligands in Functionalized Silica and Iron Oxide Nanoparticles
Authors: Renner Alexander M. , Schütz Markus B. , Moog Daniel , Fischer Thomas , Mathur Sanjay
Published: October 2019

The electrokinetic sonic amplitude (ESA) is one of the most versatile techniques for deriving the zeta potential of nanoparticles before, during and after surface functionalization with different ligands, thus overcoming current limitations of well‐established electrophoretic measurement principles. We present a novel method for direct quantification of accessible hydroxide groups available on the surface of silica nanoparticles by the ESA effect, supported by simultaneous electrical conductivity measurements. Moreover, the in‐operando determination of varying zeta potential during addition of carboxylic acids demonstrate a profound way to quantify surface‐bound ligands, which still poses a challenge in following the surface modification of nanoparticles. In this study, phase pure cuboidal hematite particles were chosen as a model system with an initial zeta potential between +50 and +55 mV in ethanol. Using both citric acid and 10‐undecynoic acid as surface‐modifiers, the correlation between the degree of surface functionalization and zeta potential was investigated. The decrease of zeta potential of hematite particles during the titration of 10‐undecynoic acid or citric acid could be directly correlated to a successful surface functionalization in contrast to a surface protonation, which would be expected in case of both carboxylic acids. Furthermore, the addition of 10‐undecynoic acid led to a stabilization effect on the zeta potential of cuboidal hematite particles. These results highlight the hitherto unexplored potential of ESA techniques as a quantification method in nanoparticle surface modification.
Synthesis of Pyrazolin‐5‐one Derivatives Clubbed with Thiazole and/or Thiadiazole and Evaluation of Their Antioxidant and Cytotoxic Activities
Authors: k. Okla Mohammad , Alamri Saudi A. , Alaraidh Ibrahim A. , AL‐ghamdi Abdullah A. , Soufan Walid H. , Allam Ahmed A. , Fouda Moustafa M. G. , Gaffer Hatem E.
Published: October 2019

Synthesis of some new thiazolyl 2‐pyrazolin‐5‐one analogues was succeeded through the reaction of 3‐methyl‐1‐thiocarbamoyl‐2‐pyrazolin‐5‐one with different α‐halogenated derivatives via different routes. The physical and spectral analysis techniques were performed to demonstrate the proper structures of all incorporated analogues. The synthesized derivatives were investigated as cytotoxic agents against some important cell lines, in which the results displayed persuasive activities relative to the results of antibiotic standards. In addition, the antioxidant activity of the synthesized analogues was evaluated using ABTS•+ method. The preps analogues displayed respectable results as antioxidant agents, especially derivatives 14 a‐c and 11 a‐c due to the existence of thiadiazolyl and bis‐thaizolyl arms for pyrazoline ring, respectively.
Copper‐Mediated Decarboxylative C–H Arylation of Phenol Derivatives with ortho‐Nitrobenzoic Acids Using Phenanthroline‐Based Bidentate Auxiliary
Authors: Takamatsu Kazutaka , Hayashi Yoshihiro , Kawauchi Susumu , Hirano Koji , Miura Masahiro
Published: October 2019

A copper‐mediated decarboxylative C–H arylation of phenol derivatives with ortho‐nitrobenzoic acid salts via phenanthroline‐directed C–H cleavage has been developed. The N,N‐bidentate phenanthroline auxiliary uniquely promotes the reaction only in the presence of a copper salt to produce the corresponding biaryls in acceptable yields. Moreover, the directing group can be easily introduced and removed. Additionally, preliminary computational mechanistic studies with DFT have also been performed.
Electrocatalytic Water Oxidation with Surface Anchored Mononuclear Manganese (II) ‐ Polypyridine Complexes
Authors: Mahanta Abhinandan , Barman Koushik , Jasimuddin Sk
Published: October 2019

Catalytic oxidation of water by manganese complexes is of great interest because it can serve as a model for the natural oxygen evolving complex, Mn4CaO5. Complex compounds are highly active and tunable, but their limited stability and solubility restrict them for practical water oxidation applications. In the present article we have prepared surface anchored Mn(II)‐complexes, [MnII(H2O)2(X)2(dcbpy)] (where dcbpy= 4,4′‐dicarboxy‐2,2′‐bipyridine; X=acetate, sulphate, chloride ions) on gold electrode surface using self‐assembly process and applied for the electrocatalytic oxidation of water in neutral pH. The modified electrode was characterized by using different spectral, microscopic and electrochemical techniques. The Mn(II)‐acetate containing gold electrode (Mn(II)‐dcbpy‐Au) electrocatalytically oxidized water at a current density of 1.6 mA cm−2 with low overpotential ∼ 310 mV and a Tafel slope of 56 mV/decade. The modified electrode showed high electrochemical stability during controlled potential electrolysis. It was also observed that the Mn(II)‐acetate immobilized on dcbpy‐Au electrode showed higher electrocatalytic activity in oxidation of water than Mn(II)‐chloride or Mn(II)‐sulfate containing dcbpy‐Au electrode. The newly in‐situ generated Mn(II)‐complex modified electrode is inexpensive and highly efficient for the catalytic oxidation of water than the surface bound Mn‐based electrocatalysts reported previously.
Metal‐Free One‐Pot Three‐Component Synthesis of Quinazoline Derivatives via Peroxide‐Mediated Direct Oxidative Amination of C(sp3)–H Bonds
Authors: Huynh Tien V. , Doan Son H. , Trinh Khang H. , Ly Trang H. , Phan Anh L. T. , Nguyen Tung T. , Phan Anh N. Q. , Phan Nam T. S.
Published: October 2019

An efficient, one‐pot synthesis of 4‐substituted quinazoline derivatives via direct oxidative amination of C(sp3)–H bonds was demonstrated. The nature of the oxidant exhibited a considerable effect on the reaction, and tert‐butyl hydroperoxide in decane emerged as the best option. A variety of C1 sources could be used, affording 4‐substituted quinazolines in good yields. The three‐component reaction proceeded readily without any added catalyst, in which acetic acid from ammonium acetate was essential for the catalytic cycle. This protocol would offer a complementary pathway to previous methods in the synthesis of 4‐substituted quinazoline derivatives.
Copper(I)‐Catalyzed Azide‐Alkyne Cycloaddition Microwave‐Assisted: Preparation of 7‐(4‐Substituted‐1H‐1,2,3‐Triazol‐1‐yl)‐Fluoroquinolones
Authors: Hernández‐López Hiram , Leyva‐Ramos Socorro , Moncada‐Martínez Rosa Delia , López Jesús Adrián , Cardoso‐Ortiz Jaime
Published: October 2019

Nowadays, the pharmaceutical industry faces the challenge of innovating and increasing the productivity of new medicines due to the increasing multidrug resistance among bacteria, viruses and fungi. The main objective of the present study is connected quinolone and triazole molecules to enhance and broad antibacterial spectrum as well as to have multiple mechanisms of action. Preparation of 4‐substituted‐1H‐1,2,3‐triazol‐1‐yl in C‐7 of 6‐fluoro‐ and 6,8‐difluoro‐quinolone ring is showed. The synthesis involved the preparation of intermediate ethyl 7‐azide‐1‐ethyl‐fluoroquinolone‐3‐carboxylate, followed by copper(I)‐catalyzed azide‐alkyne cycloaddition to give 13 derivatives. The cycloaddition was carried out by two different methods, where it was observed that the microwave radiation was the best reaction condition, obtaining a range of yields of 47–93%, at 140 °C, 125Wmax for 10 minutes. Therefore, this methodology provided an easy pathway to synthesize a library of fluoroquinolones coupled to 1,2,3‐triazole, still unexplored.
Rhodanine‐Furan Bis‐Heterocyclic Frameworks Synthesis via Green One‐Pot Sequential Six‐Component Reactions: A Synthetic and Computational Study
Authors: Hooshmand Seyyed Emad , Ghadari Rahim , Mohammadian Reza , Shaabani Ahmad , Khavasi Hamid Reza
Published: October 2019

Combinatorial construction of a drug‐like library of novel rhodanine‐furan bis‐heterocyclic scaffolds has been demonstrated through a novel one‐pot sequential six‐component reaction in water under ultrasound irradiation with 100% atom economy. The process is a sequence of tandem Michael reactions followed by domino cycloaddition/zwitterionic adduct formation/Mumm rearrangement/[1+4] cycloaddition processes, involving diverse primary amines, carbon disulfide, maleic anhydride, dialkyl acetylenedicarboxylates and various isocyanides. No catalyst was required, but the use of aqueous two‐phase (on water) conditions was critical. Docking and molecular dynamics calculations performed on human aldose reductase suggest that the bis‐heterocyclic frameworks formed may be useful inhibitors of this enzyme.