bluuebunny/crossref_metadata_2025 huggingface dataset:
SHP-2 and PD-L1 Inhibition Combined with Radiotherapy Enhances Systemic Antitumor Effects in an Anti–PD-1–Resistant Model of Non–Small Cell Lung Cancer
Authors: Chen Dawei , Barsoumian Hampartsoum B. , Yang Liangpeng , Younes Ahmed I. , Verma Vivek , Hu Yun , Menon Hari , Wasley Mark , Masropour Fatemeh , Mosaffa Sara , Ozgen Tugce , Klein Katherine , Cortez Maria Angelica , Welsh James W.
Published: April 2020

Immune checkpoint inhibitors, such as anti–PD-1/PD-L1, have emerged as promising therapies for advanced non–small cell lung cancer (NSCLC). However, approximately 80% of patients do not respond to immunotherapy given alone because of intrinsic or acquired resistance. Radiotherapy (XRT) can overcome PD-1 resistance and improve treatment outcomes, but its efficacy remains suboptimal. The tyrosine phosphatase SHP-2, expressed in some cancers and in immune cells, has been shown to negatively affect antitumor immunity. Our hypothesis was that SHP-2 inhibition in combination with anti–PD-L1 would enhance immune-mediated responses to XRT and synergistically boost antitumor effects in an anti–PD-1–resistant mouse model. We treated 129Sv/Ev mice with anti–PD-1–resistant 344SQ NSCLC adenocarcinoma with oral SHP099 (a SHP-2 inhibitor) combined with XRT and intraperitoneal anti–PD-L1. Primary tumors were treated with XRT (three fractions of 12 Gy each), whereas abscopal (out-of-field) tumors were observed but not treated. XRT in combination with SHP099 and anti–PD-L1 promoted local and abscopal responses, reduced lung metastases, and improved mouse survival. XRT also increased SHP-2+ M1 tumor-associated macrophages in abscopal tumors (P = 0.019). The addition of SHP099 also associated with a higher M1/M2 ratio, greater numbers of CD8+ T cells, and fewer regulatory T cells. This triple-combination therapy had strong antitumor effects in a mouse model of anti–PD-1–resistant NSCLC and may be a novel therapeutic approach for anti–PD-1–resistant NSCLC in patients.
Marked Arterial Functional Changes in Patients With Arterial Vascular Events Across the Early Adult Lifespan
Authors: Motau Tshegofatso H. , Norton Gavin R. , Sadiq Eitzaz , Manyatsi Nomvuyo , Kolkenbeck-Ruh Andrea , Robinson Chanel , Tade Grace , Mabena Philanathi , Monareng Taalib , Naran Ravi , Peters Ferande , Peterson Vernice , Abdool-Carrim Talib , Veller Martin , Majane Olebogeng H.I. , Sareli Pinhas , Cassimjee Ismail , Modi Girish , Woodiwiss Angela J.
Published: April 2020

Objective:

The age at which arteriosclerosis begins to contribute to events is uncertain. We determined, across the adult lifespan, the extent to which arteriosclerosis-related changes in arterial function occur in those with precipitous arterial events (stroke and critical limb ischemia).

Approaches and Results:

In 1082 black South Africans (356 with either critical limb ischemia [n=238] or stroke [n=118; 35.4% premature], and 726 age, sex, and ethnicity-matched randomly selected controls), arterial function was evaluated from applanation tonometry and velocity and diameter measurements in the outflow tract. Compared with age- and sex-matched controls, over 10-year increments in age from 20 to 60years, multivariate-adjusted (including steady-state pressures) aortic pulse wave velocity, characteristic impedance (Zc), forward wave pressures (Pf), and early systolic pulse pressure amplification were consistently altered in those with arterial events. Increases in Zc were accounted for by aortic stiffness (no differences in aortic diameter) and Pf by changes in Zc and not aortic flow or wave re-reflection. Multivariate-adjusted pulse wave velocity (7.48±0.30 versus 5.82±0.15 m/s,
P
<0.0001), Zc (
P
<0.0005), and Pf (
P
<0.0001) were higher and early systolic pulse pressure amplification lower (
P
<0.0001) in those with precipitous events than in controls. In comparison to age- and sex-matched controls, independent of risk factors, pulse wave velocity, and Zc (
P
<0.005 and <0.05) were more closely associated with premature events than events in older persons and Pf and early systolic pulse pressure amplification were at least as closely associated with premature events as events in older persons.

Conclusions:

Arteriosclerosis-related changes in arterial function are consistently associated with arterial events beyond risk factors from as early as 20 years of age.
Macrophages Promote Aortic Valve Cell Calcification and Alter STAT3 Splicing
Authors: Raddatz Michael A. , Huffstater Tessa , Bersi Matthew R. , Reinfeld Bradley I. , Madden Matthew Z. , Booton Sabrina E. , Rathmell W. Kimryn , Rathmell Jeffrey C. , Lindman Brian R. , Madhur Meena S. , Merryman W. David
Published: April 2020

Objective:

Macrophages have been described in calcific aortic valve disease, but it is unclear if they promote or counteract calcification. We aimed to determine how macrophages are involved in calcification using the
Notch1
+/−
model of calcific aortic valve disease.

Approach and Results:

Macrophages in wild-type and
Notch1
+/−
murine aortic valves were characterized by flow cytometry. Macrophages in
Notch1
+/−
aortic valves had increased expression of MHCII (major histocompatibility complex II). We then used bone marrow transplants to test if differences in
Notch1
+/−
macrophages drive disease.
Notch1
+/−
mice had increased valve thickness, macrophage infiltration, and proinflammatory macrophage maturation regardless of transplanted bone marrow genotype. In vitro approaches confirm that
Notch1
+/−
aortic valve cells promote macrophage invasion as quantified by migration index and proinflammatory phenotypes as quantified by Ly6C and CCR2 positivity independent of macrophage genotype. Finally, we found that macrophage interaction with aortic valve cells promotes osteogenic, but not dystrophic, calcification and decreases abundance of the STAT3β isoform.

Conclusions:

This study reveals that
Notch1
+/−
aortic valve disease involves increased macrophage recruitment and maturation driven by altered aortic valve cell secretion, and that increased macrophage recruitment promotes osteogenic calcification and alters STAT3 splicing. Further investigation of STAT3 and macrophage-driven inflammation as therapeutic targets in calcific aortic valve disease is warranted.
Coronary Endothelial Dysfunction Is Associated With Increased Risk of Incident Atrial Fibrillation
Authors: Corban Michel T. , Godo Shigeo , Burczak Daniel R. , Noseworthy Peter A. , Toya Takumi , Lewis Bradley R. , Lerman Lilach O. , Gulati Rajiv , Lerman Amir
Published: April 2020

Background

Coronary artery disease risk factors are associated with atrial fibrillation (
AF
) and coronary endothelial dysfunction (
CED
). We hypothesized that
CED
is associated with increased risk of incident
AF
among patients with chest pain and nonobstructive coronary artery disease.

Methods and Results

Three hundred patients with chest pain, nonobstructive coronary artery disease, and no history of
AF
underwent intracoronary acetylcholine infusion for evaluation of baseline epicardial (decrease in mid–left anterior descending coronary artery diameter in response to acetylcholine) and microvascular (<50% increase in coronary blood flow in response to acetylcholine)
CED
. Primary outcome was incident
AF
over a mean follow‐up period of 10.5±5.5 years. Mean age was 53.3±10.8 years, and 70% were women. Baseline clinical and echocardiographic characteristics were similar between patients with
CED
(n=256) and those with normal endothelial function (n=44). Overall, 35 of 300 (12%) patients developed
AF
, among whom 34 of 35 (97%) had
CED
at baseline. Compared with normal endothelial function, the presence of
CED
was associated with 11% increased absolute risk and 5.8‐fold increased relative risk of incident
AF
. Moreover,
CED
(
odds ratio
, 3.87; 95%
CI
, 1.27–47.0) and increased (>34 mL/m
2
) left atrial volume index (odds ratio, 3.87; 95%
CI
, 1.60–9.11) were independent predictors of incident
AF
.

Conclusions

Patients with normal coronary endothelial function, as compared with those with
CED
and similar
AF
risk factors, have significantly lower incidence of
AF
on long‐term follow‐up. The potential mechanistic link between vascular dysfunction and
AF
development warrants further investigation.
Outcomes and Care Quality Metrics for Women of Reproductive Age Living With Rheumatic Heart Disease in Uganda
Authors: Chang Andrew Y. , Nabbaale Juliet , Okello Emmy , Ssinabulya Isaac , Barry Michele , Beaton Andrea Z. , Webel Allison R. , Longenecker Chris T.
Published: April 2020

Background

Rheumatic heart disease disproportionately affects women of reproductive age, as it increases the risk of cardiovascular complications and death during pregnancy and childbirth. In sub‐Saharan Africa, clinical outcomes and adherence to guideline‐based therapies are not well characterized for this population.

Methods and Results

In a retrospective cohort study of the Uganda rheumatic heart disease registry between June 2009 and May 2018, we used multivariable regression and Cox proportional hazards models to compare comorbidities, mortality, anticoagulation use, and treatment cascade metrics among women versus men aged 15 to 44 with clinical rheumatic heart disease. We included 575 women and 252 men with a median age of 27 years. Twenty percent had New York Heart Association Class
III
‐
IV
heart failure. Among patients who had an indication for anticoagulation, women were less likely than men to receive a prescription of warfarin (66% versus 81%; adjusted odds ratio, 0.37; 95%
CI
, 0.14–0.96). Retention in care (defined as a clinic visit within the preceding year) was poor among both sexes in this age group (27% for men, 24% for women), but penicillin adherence rates were high among those retained (89% for men, 92% for women). Mortality was higher in men than women (26% versus 19% over a median follow‐up of 2.7 years; adjusted hazard ratio, 1.66; 95%
CI,
1.18–2.33).

Conclusions

Compared with men, women of reproductive age with rheumatic heart disease in Uganda have lower rates of appropriate anticoagulant prescription but also lower mortality rates. Retention in care is poor among both men and women in this age range, representing a key target for improvement.
Mobile Stroke Unit Computed Tomography Angiography Substantially Shortens Door-to-Puncture Time
Authors: Czap Alexandra L. , Singh Noopur , Bowry Ritvij , Jagolino-Cole Amanda , Parker Stephanie A. , Phan Kenny , Wang Mengxi , Sheth Sunil A. , Rajan Suja S. , Yamal Jose-Miguel , Grotta James C.
Published: April 2020

Background and Purpose—

Endovascular thrombectomy (ET) door-to-puncture time (DTPT) is a modifiable metric. One of the most important, yet time-consuming steps, is documentation of large vessel occlusion by computed tomography angiography (CTA). We hypothesized that obtaining CTA on board a Mobile Stroke Unit and direct alert of the ET team shortens DTPT by over 30 minutes.

Methods—

We compared DTPT between patients having CTA onboard the Mobile Stroke Unit then subsequent ET from September 2018 to November 2019 and patients in Mobile Stroke Unit from August 2014 to August 2018, when onboard CTA was not yet being used. We also correlated DTPT with change in National Institutes of Health Stroke Scale between baseline and 24 hours.

Results—

Median DTPT was 53.5 (95% CI, 35–67) minutes shorter with onboard CTA and direct ET team notification: 41 minutes (interquartile range, 30.0–63.5) versus 94.5 minutes (interquartile range, 69.8–117.3;
P
<0.001). Median on-scene time was 31.5 minutes (interquartile range, 28.8–35.5) versus 27.0 minutes (interquartile range, 23.0–31.0) (
P
<0.001). Shorter DTPT correlated with greater improvement of National Institutes of Health Stroke Scale (correlation=−0.2,
P
=0.07).

Conclusions—

Prehospital Mobile Stroke Unit management including on-board CTA and ET team alert substantially shortens DTPT.

Registration—

URL:
https://clinicaltrials.gov
; Unique identifier: NCT02190500.
Applicability of the UNIDROIT Principles as the Law Governing the Merits of Arbitration in the Gulf Cooperation Council Countries
Authors: Dawwas Amin , Kameel Tareq
Published: April 2020

According to the principle of party autonomy, the disputant parties may choose the law applicable to the merits of international commercial arbitration. In the absence of the parties’ choice, the arbitral tribunal shall determine this law. This article discusses the applicability of ‘rules of law’, namely the UNIDROIT Principles of International Commercial Contracts (UNIDROIT Principles) to the merits of the dispute. It shows whether the UNIDROIT Principles can be selected by the disputant parties or the arbitral tribunal to govern the subject of the dispute under the Arbitration Laws of the Gulf Cooperation Council (GCC) Countries as well as the Constitution and the Arbitral Rules of Procedure of the GCC Commercial Arbitration Center (GCCCAC).
Stabreimende Wortpaare in Wolframs “Willehalm”, “Titurel” und in seiner Lyrik
Authors: Jeep John M.
Published: April 2020

This study presents a first-time complete accounting and analysis of the alliterating word-pairs in Wolfram’s “Willehalm,” “Titurel,” and his poetry, representing the completion of a project to survey Wolframs’ complete oeuvre. Each pair is described philologically within the work in which it appears, relevant earlier or parallel occurrences are noted, and on occasion the further life of the pair is discussed. A complete listing integrates the 98 pairs from “Parzival.” This rounds out studies of the major Middle High German classical works of courtly literature, cataloguing Wolfram’s use of the rhetorical device following similar studies of Hartmann von Aue and Gottfried von Strassburg.
Two New Species of Begonia (Begoniaceae, Section Petermannia) from Mount Sidole, Central Sulawesi, Indonesia

Authors: DAYANTI EKA P. , PITOPANG RAMADANIL , ARDI WISNU H. , THOMAS DANIEL C.
Published: April 2020

Begonia sidolensis and Begonia rolandfadlii from Gunung Sidole (Parigi Moutong Regency, Central Sulawesi, Indonesia) are proposed as new species. Detailed descriptions and photo plates of both species are provided. Both species are provisionally assessed as belonging to the Vulnerable IUCN category.
Aspidistra xichouensis (Asparagaceae), a new species from the karst region in southeastern Yunnan, China

Authors: CAI LEI , PAN BO , LIN CHUN-RUI , DAO ZHI-LING , HU GUANG-WAN
Published: April 2020

Aspidistra xichouensis, a new species of Asparagaceae from Xichou County, Yunnan Province, China, is described and illustrated. The new species is similar to A. minutiflora, A. graminifolia and A. cylindrica in the shape of leaf blade and the size and structure of flowers, but can be easily distinguished mainly by the conspicuous petiole, upright peduncle, and erect flowers with 4(–5) perianth lobes. The results of comparisons with the related species are also provided.
Colorimetric Study of the Interaction Between Gold Nanoparticles and a Series of Amino Acids
Authors: Zhu Xiaoli , Yang Qianlu , Huang Junyi , Suzuki Iwao , Li Genxi
Published: April 2020

Study of the interaction between gold nanoparticles and a series of amino acids is reported in this paper. Amino acids with thiol, amine, or hydroxyl groups in their side chains are proven to make gold nanoparticles self-assemble under certain conditions. There is a progression of the
effect on self-assembly of gold nanoparticles from hydroxyl < amine < thiol. Meanwhile, concentration of amino acids and the pH value of the solution have been found to be important for amino acids to exert the interesting effect on self-assembly of the nanoparticles.
Synthesis of Ordered Macroporous Pt/Ru Nanocomposites for the Electrooxidation of Methanol
Authors: Zhang Dai , Ding Ya , Gao Wei , Chen Hong-Yuan , Xia Xing-Hua
Published: April 2020

Highly catalytic PtRu catalysts with different molar ratios of Pt to Ru have been synthesized by using the inverted colloidal crystals template technique. Three-dimensional ordered Pt/Ru alloys with pore size of 320 nm could be conveniently obtained by electrochemical codeposition of
metal precursors inside the voids of the template. The structural and chemical properties of the macroporous catalysts were studied by using SEM, XPS and XRD methods. The decomposition and oxidation of methanol on the macroporous catalyst surfaces with different Pt and Ru molar ratios (Pt100Ru0,
Pt90Ru10, Pt80Ru20, Pt70Ru30 and Pt56Ru44) were systemically discussed. Potentiostatic experiments showed that the special structure characteristics (e.g., interconnected pore framework and the flexible
curvature) lead to enhanced methanol oxidation efficiency on the macroporous materials as compared to the directly deposited catalyst. These results demonstrate that the three-dimensional ordered porous bimetallic catalysts are promising alternatives for developing high performance DMFC anodic
catalysts, especially for the fabrication of microfuel cells.
Performance and Application of Far Infrared Rays Emitted from Rare Earth Mineral Composite Materials
Authors: Liang Jinsheng , Zhu Dongbin , Meng Junping , Wang Lijuan , Li Fenping , Liu Zhiguo , Ding Yan , Liu Lihua , Liang Guangchuan
Published: April 2020

Rare earth mineral composite materials were prepared using tourmaline and cerous nitrate as raw materials. Through characterization by scanning electron microscopy, X-ray diffraction, X-ray photo-electron spectroscopy, dynamic contact angle meter and tensiometer, and Fourier transform
infrared spectroscopy, it was found that the composite materials had a better far infrared emitting performance than tourmaline, which depended on many factors such as material composition, microstructure, and surface free energy. Based on the results of the flue gas analyzer and the water
boiling test, it was found that the rare earth mineral composite materials could accelerate the combustion of liquefied petroleum gas and diesel oil. The results showed that the addition of Ce led to the improvement of far infrared emitting performance of tourmaline due to the decrease of
cell volume caused by the oxidation of more Fe2+ ions and the increase of surface free energy. The application of rare earth mineral composite materials to diesel oil led to a decrease in surface tension and flash point, and the fuel saving ratio could reach 4.5%. When applied to
liquefied petroleum gas, the composite materials led to the enhanced combustion, improved fuel consumption by 6.8%, and decreased concentration of CO and O2 in exhaust gases by 59.7% and 16.2%, respectively; but the temperature inside the flue increased by 10.3%.
Improved Luminescence Properties of Europium Complexes Encapsulated into Mesoporous SBA-15
Authors: Li Suwen , Song Hongwei , Li Wenlian , Lu Shaozhe , Ren Xinguang
Published: April 2020

Two kinds of Eu3+ complexes—Eu(TTA)3(TPPO)2 (TTA: thenoyltrifluoroacetone, TPPO: triphenylphosphineoxide) and Eu(BA)3(TPPO)2 (BA: 1-benzoylacetone)—were fully encapsulated, uniformly distributed into the channels of
unmodified and modified SBA-15, and structurally characterized. The luminescent properties of the encapsulated complexes were systematically studied in contrast to the pure complexes. The results indicate that the excitation bands assigned to the π–π* electron
transition of the ligands for Eu3+ complexes encapsulated in SBA-15 were split into different components, and the 5D0-7F0 transitions became partly allowed. The emission lines for the 5D0-7F2
transitions became broader and the relative intensity for different crystal field components varied greatly in comparison to the pure complex. Most importantly, the photostability and thermostability of the emissions improved considerably.
Synthesis and Cathodoluminescence of β-Ga2O3 Nanowires with Holes
Authors: Zhang Xitian , Liu Zhuang , Hark Suikong
Published: April 2020

Gallium oxide nanowires were synthesized on Si (001) substrate by chemical vapor deposition, using a Ga/Ga2O3 mixture as a precursor and Au as a catalyst. The structure of the as-synthesized products was examined by X-ray powder diffraction and high-resolution
transmission electron microscopy, and found to be monoclinic β-Ga2O3. The morphologies of the β-Ga2O3 nanowires were characterized by scanning electron microscopy. The majority of the nanowires contain holes along their length,
but a few were also found without holes. The holes are believed to be formed by the reaction of adsorbed Ga droplets on reactive terminating surfaces of the nanowires. For nanowires where these reactive surfaces are not exposed, the reaction of Ga is retarded. Cathodoluminescence (CL) of the
nanowires was measured. Three emission bands centered at 376, 454, and 666 nm, respectively, were observed.
Two-Photon Absorption and Degenerate Four-Wave Mixing Studies of Sulfide Semiconductor Nanoparticles in Polymeric Solutions
Authors: Jia Wenling , Guo Fengqi , Douglas Elliot P. , Sun Wenfang
Published: April 2020

The two-photon absorption coefficients (β) and the third-order nonlinear susceptibilities (χ(3)) of several semiconductor nanoparticles (CdS, CdxAg1–xS, and core–shell CdS/Ag2S) that are confined
and stabilized by random and block ionomers have been measured by nonlinear transmission and degenerate four-wave mixing techniques using 21 picosecond laser pulses at near-infrared spectral region. The imaginary part of the third-order nonlinear susceptibility that is related to the two-photon
absorption coefficient was then calculated. The absorptive nonlinearity of the nanoparticles (2∼9 nm) was found to be dependent on the particle size, composition and wavelength, i.e., larger CdS particles exhibit higher two-photon absorption coefficients and the presence of Ag improves
two-photon absorption of CdS nanoparticles. The obtained two-photon absorption coefficients of nanoparticles corrected for their volume fraction in solution are significantly greater that those of corresponding bulk semiconductors.
Self-Organized ZnSe Quantum Dots: Synthesis and Characterization
Authors: Kaushik Diksha , Singh R. R. , Sharma A. B. , Gupta D. , Sharma M. , Pandey R. K.
Published: April 2020

Self-organized ZnSe quantum dots (Q-ZnSe) were grown on indium tin oxide substrate using wet chemical technique without or in presence of copper and manganese dopants. The structural, morphological and luminescence properties of the as grown Q-dot films have been investigated, using
X-ray diffraction, transmission electron microscopy, atomic force microscopy and optical and luminescence spectroscopy. Composition of the samples were analyzed using atomic absorption spectroscopy. The quantum dots have been shown to deposit in a compact, uniform and organized array on the
indium tin oxide substrate. The size dependent blue shift in the experimentally determined absorption edge has been compared with the theoretical predictions based on the effective mass and tight binding approximations. It is shown that the experimentally determined absorption edges depart
significantly from the theoretically calculated values. The photoluminescence properties of the undoped as well as doped Q-ZnSe have also been discussed.
Conducting Polymer/Clay Nanocomposites and Their Applications
Authors: Fei Fang Fei , Jin Choi Hyoung , Joo Jinsoo
Published: April 2020

This review aims at reporting on interesting and potential aspects of conducting polymer/clay nanocomposites with regard to their preparation, characteristics and engineering applications. Various conducting polymers such as polyaniline, polypyrrole and copolyaniline are introduced
and three different preparation methods of synthesizing conducting polymer/clay nanocomposites are being emphasized. Morphological features, structure characteristics and thermal degradation behavior are explained based on SEM/TEM images, XRD pattern analyses and TGA/DSC graphs, respectively.
Attentions are also being paid on conductive/magnetic performances as well as two potential applications in anti-corrosion coating and electrorheological (ER) fluids.
Polymerically Modified Layered Silicates: An Effective Route to Nanocomposites
Authors: Zhang Jinguo , Manias E. , Wilkie Charles A.
Published: April 2020

Polymer/clay nanocomposites have been under an extensive investigation for about 15 years. Traditional methods to modify the clay are usually limited to small organic cations, preferably containing long alkyl chain(s), which are exchanged with the inorganic cations in the clay gallery.
This article provides a comprehensive review on the strategies for clay modification using polymeric surfactants or polycations: from the synthesis of such surfactants, through the preparation of the polymerically modified clays, and to the fabrication of the respective polymer nanocomposites
and their properties.
Melt Mixed Composites of Poly(ethylene-co-methacrylic acid) Ionomers and Multiwall Carbon Nanotubes: Influence of Specific Interactions
Authors: Bose Suryasarathi , Bhattacharyya Arup R. , Chawley Manish , Kodgire Pravin V. , Kulkarni Ajit R. , Misra Ashok , Pötschke Petra
Published: April 2020

Multiwall carbon nanotubes (MWNT) were melt-mixed with poly(ethylene-co-methacrylic acid) ionomers (Surlyn) using twin screw microcompounder. The specific interactions existing between the Na+ moieties in Surlyn and the π electron clouds of MWNT were supported by
FTIR and Raman spectroscopic analysis. SAXS scattering patterns were found to be progressively broadened in presence of MWNT in Surlyn/MWNT composites. Morphological investigations revealed selective clustering of MWNT in the vicinity of the ionic domains in Surlyn. Further, the domain size
of the ionic clusters was found to increase with increasing MWNT content disrupting the ionic pairs apart in the ionic domain. The melt rheological response of Surlyn was significantly affected in presence of MWNT and was profoundly dependent on the ionic clusters. The state of dispersion
of MWNT was assessed by AC electrical conductivity measurements. The associated percolation threshold was observed between 1.5–2 wt% of MWNT.
Synthesis and Properties of Melamine-Formaldehyde/Montmorillonite Nanocomposites
Authors: Wang Haitao , Meng Xiangfu , Qian Zhongzhong , Zhou Hu , Ding Yanfen , Zhang Shimin , Yang Mingshu
Published: April 2020

In this paper, intercalated and partially exfoliated melamine-formaldehyde (MF)/montmorillonite (MMT) nanocomposites have been synthesized successfully via in-situ polymerization based on pristine montmorillonite, acidified montmorillonite and organic modified montmorillonite
respectively. The obtained nanocomposites were characterized by XRD, TEM, TGA, and Raman spectroscopy. Free formaldehyde content of those composites was also determined by acetyl acetone technique. It was found that acidified montmorillonite and organic modified montmorillonite could catalyze
the polycondensation reaction of methylolmelamines. The thermal stability and chemical resistance of those two nanocomposites were also improved dramatically compared to pure melamine-formaldehyde resin.
Synthesis and Characterization of SiO2/(PMMA/Fe3O4) Magnetic Nanocomposites
Authors: Wang Zhifei , Guo Yafei , Li Song , Sun Yueming , He Nongyue
Published: April 2020

Magnetic silica nanocomposites (magnetic nanoparticles core coated by silica shell) have the wide promising applications in the biomedical field and usually been prepared based on the famous Stöber process. However, the flocculation of Fe3O4 nanoparticles
easily occurs during the silica coating, which limits the amount of magnetic silica particles produced in the Stöber process. In this paper, PMMA/Fe3O4 nanoparticles were used in the Stöber process instead of the “nude” Fe3O4
nanoparticles. And coating Fe3O4 with PMMA polymer beforehand can prevent magnetic nanoparticles from the aggregation that usually comes from the increasing of ionic strength during the hydrolyzation of tetraethoxysilane (TEOS) by the steric hindrance. The results show
that the critical concentration of magnetic nanoparticles can increase from 12 mg/L for “nude” Fe3O4 nanoparticles to 3 g/L for PMMA/Fe3O4 nanoparticles during the Stöber process. And before the deposition of silica shell, the surface
of PMMA/Fe3O4 nanoparticles had to be further modified by hydrolyzing them in CH3OH/NH3˙H2O mixture solution, which provides the carboxyl groups on their surface to react further with the silanol groups of silicic acid.
Oxidized Wax as Compatibilizer in Linear Low-Density Polyethylene-Clay Nanocomposites: X-ray Diffraction and Dynamic Mechanical Analysis
Authors: Geethamma V. G. , Luyt Adriaan S.
Published: April 2020

Oxidized paraffin wax was used as a compatibilizer in composites of linear low-density polyethylene and layered nano silicate clays. X-ray diffraction analyses were carried out to investigate the crystalline morphology of five types of clays, oxidized wax, and their composites with
LLDPE. The composites exhibited different X-ray diffraction and dynamic mechanical behaviour in the presence of different clays. Generally, the composites retained the partially crystalline behaviour of LLDPE, and no exfoliation was observed. Increased amount of wax did not change the morphology
in most cases. The incorporation of clay resulted in an observable increase in the storage modulus of LLDPE. These values also increased with the addition of oxidized wax for most of the composites. The loss modulus increased with the amount of clay, irrespective of its nature. In most cases
these values also increased with the incorporation of wax. The composites with 10% clay and 10% oxidized wax showed the highest storage and loss moduli, irrespective of the nature of the clay. The tan δ values did not change considerably with the addition of clay or wax.
The Location and Extent of Exfoliation of Clay on the Fracture Mechanisms in Nylon 66-Based Ternary Nanocomposites
Authors: Dasari Aravind , Yu Zhong-Zhen , Mai Yiu-Wing , Yang Mingshu
Published: April 2020

The primary focus of this work is to elucidate the location and extent of exfoliation of clay on fracture (under both static and dynamic loading conditions) of melt-compounded nylon 66/clay/SEBS-g-MA ternary nanocomposites fabricated by different blending sequences. Distinct microstructures
are obtained depending on the blending protocol employed. The state of exfoliation and dispersion of clay in nylon 66 matrix and SEBS-g-MA phase are quantified and the presence of clay in rubber is shown to have a negative effect on the toughness of the nanocomposites. The level of toughness
enhancement of ternary nanocomposites depends on the blending protocol and the capability of different fillers to activate the plastic deformation mechanisms in the matrix. These mechanisms include: cavitation of SEBS-g-MA phase, stretching of voided matrix material, interfacial debonding
of SEBS-g-MA particles, debonding of intercalated clay embedded inside the SEBS-g-MA phase, and delamination of intercalated clay platelets. Based on these results, new insights and approaches for the processing of better toughened polymer ternary nanocomposites are discussed.
Influence of Mineral on the Load Deformation Behavior of Polymer in Hydroxyapatite-Polyacrylic Acid Nanocomposite Biomaterials: A Steered Molecular Dynamics Study
Authors: Bhowmik Rahul , Katti Kalpana S. , Katti Dinesh R.
Published: April 2020

Composites of hydroxyapatite and polymers are widely studied for bone replacement. To perform satisfactorily in the human body, these composites need to be biocompatible and exhibit optimum mechanical properties. The load-deformation behavior of composites is often investigated using
experimental techniques. However, the molecular mechanisms of load deformation behavior are not clearly understood. We have used Steered Molecular Dynamics to evaluate the load-deformation behavior at interfaces in polyacrylic acid-hydroxyapatite (HAP) composite models. The polymer is pulled
at constant velocity in close proximity of HAP. On comparing the results obtained for deformation behavior of polymer in vicinity of mineral and in the absence of mineral, it was found that energy required to pull the polymer in close proximity of HAP is significantly higher. Also, structural
details of the load transfer mechanisms in composite were investigated under both conditions. Our simulations indicate that there is a significant role of mineral-polymer interactions on the mechanical response of polymer.
Effect of Silica Nanoparticles on Reinforcement of Poly(phenylene ether) Based Thermoplastic Elastomer
Authors: Gupta Samik , Maiti Parnasree , Krishnamoorthy Kumar , Krishnamurthy Raja , Menon Ashok , Bhowmick Anil K.
Published: April 2020

Reinforcement of a novel poly(phenylene ether) (PPE) based thermoplastic elastomer (TPE), i.e., styrene-ethylene-butylene-styrene (SEBS)/ethylene vinyl acetate (EVA) and PPE-polystyrene (PS), was studied to develop a reinforced thermoplastic elastomer or thermoplastic vulcanizate (TPV).
An effort was made to reinforce selectively the elastomeric dispersed phase of EVA by silica nanoparticles and silica sol–gel precursors, like alkoxy orthosilanes, using twin-screw extrusion and injection molding processes. Improvement of tensile strength and percent elongation at break
was observed both with silica nanoparticles and tetraethoxy orthosilane (TEOS). Addition of TEOS transformed the dispersed EVA lamellar morphology into semispherical domains as a consequence of possible crosslinking. Soxhlet extraction was done on the silica and TEOS reinforced materials.
The insoluble residues collected from both the silica and TEOS reinforced samples were analyzed in detail using both morphological and spectroscopic studies. This extensive study also provided an in-depth conceptual understanding of the PPE based TPE behavior upon reinforcement with silica
nanoparticles and silica sol–gel precursors and the effect of reinforcement on recycling behavior.
Non-Viral Lipid-Based Nanoparticles for Targeted Cancer Systemic Gene Silencing
Authors: Moreira J. N. , Santos A. , Moura V. , Pedroso de Lima M. C. , Simões S.
Published: April 2020

New molecular biology techniques have uncovered the hidden role of genes in cancer. Identification of activated oncogenes, as fundamental genetic differences relative to normal cells, has made it possible to consider such genes as targets for antitumor therapy, namely by applying gene
silencing strategies. In this regard, antisense oligonucleotides or small interfering RNAs, constitute promising therapeutic tools. The widespread clinical application of such molecules as modulators of gene expression, is still dependent on several aspects that limit their bioavailability,
including: enhanced biological stability, favourable pharmacokinetics, enhanced tumor cell uptake and, consequently, efficient targeted delivery. One of the most promising strategies to overcome the barriers faced by gene silencing molecules, upon systemic administration, involves the use
of lipid-based nanoparticles. The first part of this review aims at providing the reader with the molecular mechanism of action of the most important gene silencing molecules used in anticancer therapy. The primary obstacle for translating gene silencing technology from an effective research
tool into a feasible therapeutic strategy remains its efficient delivery to the targeted cell type in vivo. Therefore, an overview of different lipid-based strategies for nucleic acid delivery will be presented on the second part. As we learn more about the pharmacokinetics and pharmacodynamics
of the carrier and/or of the gene silencing molecules, it will be possible to further improve the delivery strategy that likely in the future will lead to the ideal non-viral particle for targeted cancer systemic gene silencing.
Synthesis, Physicochemical Characterization and MR Relaxometry of Aqueous Ferrofluids
Authors: Hodenius Michael A. J. , Niendorf Thoralf , Krombach Gabriele A. , Richtering Walter , Eckert Thomas , Lueken Heiko , Speldrich Manfred , Günther Rolf W. , Baumann Martin , Soenen Stefaan J. H. , De Cuyper Marcel , Schmitz-Rode Thomas
Published: April 2020

The synthesis and characterization of ferrofluid based MR contrast agents, which offer R2* versatility beyond that of ferucarbotran, is described. Ferrofluids were formed after stabilizing magnetite cores with dodecanoic acid (a), oleic acid (b), dodecylamine (c), citric acid (d)
or tartaric acid (e). Core sizes were deduced from TEM micrographs. Magnetic properties were determined by SQUID magnetometry. Hydrodynamic particle diameters were determined by dynamic light scattering measurements. Zeta potentials were measured by combining laser Doppler velocimetry and
phase analysis light scattering. Iron contents were evaluated colorimetrically. MR relaxometry including R1 and R2* was conducted in vitro using homogeneous ferrofluid samples. The average core diameters of ferrofluids a, b and c equaled 9.4±2.8 nm and approximately 2 nm
for ferrofluids d and e. Magnetization measurements at 300 K revealed superparamagnetic behaviour for the dried 9 nm diameter cores and paramagnetic-like behaviour for the dried cores of ferrofluids d and e. Iron contents were between 32–75 mg Fe/mL, reflecting the ferrofluids' high
particle concentrations. Hydrodynamic particle diameters equaled 100–120 nm (a, b and c). For the ferrofluids a, b, d and e coated with anions, strong negative zeta potential values between −27.5 mV and −54.0 mV were determined and a positive zeta potential value of +33.5
mV was found for ferrofluid c, covered with cationic dodecylammonium ions. MR relaxometry yielded R1-values of 1.9±0.3 (a), 4.0±0.8 (b), 5.2±1.0 (c), 0.124±0.002 (d) and 0.092±0.005 s−1 mM−1 (e), and R2*-values of 856±24
(a), 729±16 (b), 922±29 (c), 1.7±0.05 (d) and 0.49±0.05 s−1 mM−1 (e). Thus, the synthesized ferrofluids reveal a broad spectrum of R2* relaxivities. As a result, the various MR contrast agents have a great potential to be used
in studies dealing with malignant tissue targeting or molecular imaging.
Negative Temperature Coefficient of Single-Walled Carbon Nanotube-Gold Nanoparticle Hybrid Structures
Authors: Songmee N. , Daothong S. , Singjai P.
Published: April 2020

Single-walled carbon nanotubes (SWNTs) were grown on gold nanoparticle (GNP) coated quartz substrates by alcohol catalytic chemical vapor deposition. The GNP coated substrates were coated with Co catalyst by a dip-coat method. The growth was then carried out at 800 °C under a pressure
of 10 Torr in an atmosphere of ethanol vapor for 30 min. Characterizations have shown larger SWNT diameters with higher negative temperature coefficients for GNP coated substrates as compared to those of quartz substrates without GNPs. It is attributed that SWNT-GNP hybrid structures have
a higher fraction of semiconductor-type pathways.
Luminescence Tuning of Amorphous Si Quantum Dots Prepared by Plasma-Enhanced Chemical Vapor Deposition
Authors: Kang S. M. , Yoon S. G. , Kim S.-W. , Yoon D. H.
Published: April 2020

Amorphous Si (a-Si) quantum dots (QDs) embedded in a silicon nitride film were prepared by a plasma-enhanced chemical vapor deposition (PECVD) technique using gaseous mixtures of silane, hydrogen and nitrogen. We observed that the Si QDs had an amorphous structure from the Raman
spectroscopy measurement. The Fourier transform infrared (FTIR) spectra showed that the relative transmittance of the SiH bands decreased, but that of the NH bands increased, with increasing nitrogen flow rate. During the deposition of SiNx, the number of dangling bonds of
silicon acting as nucleation sites increased. As the hydrogen flow rate increased the growth rate decreased, due to the reduction in the hydrogen partial pressure. The hydrogen and nitrogen gas flow rates were found to be important parameters for determining the size of the a-Si QDs.
In addition, we observed that the PL peak shifted toward a higher energy with increasing hydrogen and nitrogen gas flow rates, which was attributed to the increase in the quantum confinement effect in the a-Si QDs.
Characteristics of Hydrothermally Deposited Nanostructured (NiZn) Fe2O4 Films
Authors: Pramoda K. P. , Mun Tang Seow , Goh G. K. L. , Lok B. K. , Lu Albert
Published: April 2020

This work is devoted to the hydrothermal deposition of nanostructured (NiZn) Fe2O4 films on PCB substrates and their structural, morphological and electro-magnetic characterisation. Ferrite films were prepared by the hydrothermal treatment of iron, nickel and zinc
nitrate solutions in the presence of reduced iron powder and urea at a temperature of 150 °C for 2 hrs. The resulting films with a black appearance are homogeneous without visible pores. The film formed is polycrystalline with a spinel structure and a thickness of about 1.5 μm.
Characterisation of the films by a variety of techniques showed that their magnetic and electrical properties are comparable to those of films prepared by other methods reported in the literature.
Ruthenium Interlayer as Diffusion Barrier Under Carbon Overcoat in Magnetic Recording Media
Authors: Wang Jianhui , Zhang Sam , Wang Huili , Xu Ping , Iha Dwight , Sawasaki Steven
Published: April 2020

A Magnetic film of ternary CoCrTa alloy was deposited onto textured NiP/Al substrate. Then, an atomic (8 Å) layer of ruthenium (Ru) film was sputtered before a layer of hydrogenated amorphous carbon (a-C:H) was deposited by hot filament Plasma Enhanced Chemical Vapor Deposition
method. Dynamic remanent magnetization and thickness product (MrT) measurement showed that samples without Ru interlayer were susceptible to plasma damage during carbon deposition compared to samples with Ru interlayer. The impact was more obvious as the substrate bias was increased during
carbon deposition. Having an intermediate layer of ruthenium film in between magnetic layer and carbon overcoat made magnetic performance of the film more stable. After annealed for 30 minutes under 1 atm of N2 environment, MrT values dropped drastically in samples without Ru interlayer
but varied only a little in samples with the interlayer. Water contact angle measurement showed little difference in surface energy with or without the interlayer. XPS studies indicated that Tantalum carbide formed in samples without Ru interlayer. Formation of metal carbide was not found
in samples with Ru interlayer.
Exchange Bias Phenomenology and Models of Core/Shell Nanoparticles
Authors: Iglesias Òscar , Labarta Amílcar , Batlle Xavier
Published: April 2020

Some of the main experimental observations related to the occurrence of exchange bias in magnetic systems are reviewed, focusing the attention on the peculiar phenomenology associated to nanoparticles with core/shell structure as compared to thin film bilayers. The main open questions
posed by the experimental observations are presented and contrasted to existing theories and models for exchange bias formulated up to date. We also present results of simulations based on a simple model of a core/shell nanoparticle in which the values of microscopic parameters such as anisotropy
and exchange constants can be tuned in the core, shell and at the interfacial regions, offering new insight on the microscopic origin of the experimental phenomenology. Adetailed study of the magnetic order of the interfacial spins shows compelling evidence that most of the experimentally
observed effects can be qualitatively accounted within the context of this model and allows also to quantify the magnitude of the loop shifts in striking agreement with the macroscopic observed values.
Magnetic Nanoparticles with Core/Shell Structures
Authors: Liu W. , Zhong W. , Du Y. W.
Published: April 2020

Magnetic nanoparticles with core/shell structures are an important class of functional materials, possessing unique magnetic properties due to their tailored dimensions and compositions. This paper reviews mainly our recent advances in the preparation and characterizations of core/shell
structured magnetic materials, focusing in nonmagnetic, antiferromagnetic, or ferro/ferri-magnetic shell coated magnetic core particles. And some of the unique properties of core–shell materials and their self-assembly are presented. Shell layers are shown to serve various functions.
A broad demonstration of the successful blend of these types of materials synthesis, microstructural evolution and control, new physics and novel applications that is central to research in this field is presented.
Bulrush-Like Double Perovskite: Synthesis, Tunneling Magnetoresistance, and Magnetocaloric Effects
Authors: Zhong W. , Tang N. J. , Au C. T. , Du Y. W.
Published: April 2020

The recent observation of room temperature tunneling magnetoresistance (TMR) in half-metallic A2FeMoO6 (A = Ca, Sr, Ba) double perovskites, and their importance to the emerging field of spintronics has led to considerable effort being dedicated to
detailed investigations of the physical and chemical properties of these materials. This article will present an review of our recent investigations covering the synthesis, structures, magnetic and transport properties of "bulrush-like" A2FeMoO6 (A = Sr,
Ba). Utilizing the high shape anisotropy as well as the reactivity of A2FeMoO6 to water and a sonochemical technique, we managed to manipulate the properties of grain boundary barriers, and thus put forward a new approach for the enhancement of room temperature
TMR. The magnetocaloric effects of A2FeMoO6 double perovskites will also be discussed.
Thermal Annealing Dependence of High-Frequency Magnetoimpedance in Amorphous and Nanocrystalline FeSiBCuNb Ribbons
Authors: Hernando B. , Prida V. M. , Sanchez M. L. , Olivera J. , Garcia C. , Santos J. D. , Alvarez P. , Li Sánchez J. L. , Perov N.
Published: April 2020

The magnetoimpedance (MI) effect in Fe73.5Si13.5B9Nb3Cu1 melt-spun amorphous ribbons has been studied in the frequency range (1–500 MHz). Isothermal heating treatments in a furnace have been employed to nanocrystallize the
ribbons (1 h at 565 °C in a vacuum of 10–3 mbar), while other samples were annealed at lower temperatures (400 and 475 °C during 1 h), in order to evaluate the influence of the annealing temperature on the MI effect. The high-frequency impedance was measured using
a technique based on the reflection coefficient measurements of a specific transmission line by using a network analyzer. Frequency dependence of the MI ratio, ΔZ/Z, and both resistive, ΔR/R, and reactive, ΔX/X, components of magnetoimpedance were measured
in the amorphous and annealed states, at different temperatures. A maximum value of the MI ratio of about 50% at a driving frequency of 18 MHz is obtained in the nanocrystalline (annealed at 565 °C) ribbon. Maxima for R/R of about 81% at 85 MHz and ΔX/X around 140% at 5 MHz
were also achieved. It is revealed that the microstructural evolution in the nanocrystalline sample leads to a magnetic softening, an optimum domain structure and a permeability which is sensitive to frequency and applied magnetic field, generating a large MI response.
Computational Models in Nano-Bioelectronics: Simulation of Ionic Transport in Voltage Operated Channels
Authors: Longaretti Massimo , Marino Giovambattista , Chini Bice , Jerome Joseph W. , Sacco Riccardo
Published: April 2020

In this article, a novel mathematical and computational model is proposed for the numerical simulation of Voltage Operated ionic Channels (VOC) in Nano-bioelectronics applications. This is a first step towards a multi-physics description of hybrid bio-electronical devices such as bio-chips.
The model consists of a coupled system of nonlinear partial differential equations, comprising a Poisson-Nernst-Planck system to account for electro-chemical phenomena, and a Navier-Stokes system to account for fluid-mechanical phenomena. Suitable functional iteration techniques for problem
decoupling and finite element methods for discretization are proposed and discussed. Numerical results on realistic VOCs illustrate the validity of the model and its accuracy by comparison with relevant computed channel equivalent electrical parameters with measured data.