bluuebunny/crossref_metadata_2025 huggingface dataset:
A 2D hydrodynamic model for shallow water flows with significant infiltration losses
Authors: Ni Yufang , Cao Zhixian , Liu Qing , Liu Qingquan
Published: February 2020

Infiltration losses may be significant and warrant proper incorporation into mathematical models for river floods in arid and semi‐arid areas, rainfall‐induced surface runoffs in watersheds and swashes on beaches. Here, a depth‐averaged two‐dimensional hydrodynamic model is presented for such processes based on the cell‐centred finite volume method on unstructured meshes, with the full Green‐Ampt equation evaluating the infiltration rate. A local time stepping strategy is employed along with thread parallelization with Open Multi‐processing and high‐performance computing to reduce model run time and therefore facilitate applications for large‐scale processes. The numerical solutions generally agree with the experimental and field‐measured data for typical cases with significant infiltration losses. The case study shows that neglecting infiltration leads to an overestimated discharge hydrograph, which cannot be compensated by means of varied bed resistance as estimated by Manning roughness, and the infiltration parameters play disparate roles in modifying shallow flows compared with Manning roughness. In addition, infiltration affects bed shear stress, which in turn modifies the critical bed sediment size that could be initiated for incipient motion by the flow and therefore needs to be properly accounted for when sediment transport and morphological evolution are to be resolved.
IMPACT OF HEADWATER HYDROLOGICAL DEFICIT ON THE DOWNSTREAM FLOOD‐BASED FARMING SYSTEM IN NORTHERN ETHIOPIA
Authors: Negash Emnet , Gebresamuel Girmay , Embaye Tesfa‐alem , Nguvulu Alick , Meaza Hailemariam , Gebrehiwot Misgina , Demissie Biadgilgn , Gebreyohannes Tesfaalem , Nyssen Jan , Zenebe Amanuel
Published: February 2020

Flood‐based farming is a means of improving crop production in rain‐deficit lowlands. Such spate irrigation systems are growing in importance, although the effects of headwater hydrological deficit on downstream flood farming are lacking evidence. This study investigates the impacts of headwater hydrological deficit on the extent of spate‐irrigated agriculture in the Guguf spate system. The length of canals and area of spate‐irrigated agriculture to the right and left of the Guguf River for the 1980s and 2010s were tracked using a global positioning system and mapped in a geographic information system interface, while climate data were collected from National Meteorological Agency. Trends of selected hydroclimatic variables were analysed using linear regression and the Pettitt test. The flash floods have shrunk by 7.36 × 106 m3, as a result of which the length of canals and area of spate‐based farms declined by 1.37 km and 1540 ha, i.e. 35 and 57.5%, respectively, in only three decades. This corresponds to an average withdrawal of −44.0 ha yr‾¹. A single 1 million m3 decline in flash floods caused a 366.4 ha decline in spate‐based farms. Moreover, farm fields located next to the river course are less affected, compared to those at the tail of the scheme. If the current trend continues, there is a high risk that the remaining farms currently receiving floods may find themselves outside of the spate systems. Therefore, we suggest that flood management technologies are needed to optimize the efficiency of soil moisture in the spate system. © 2020 John Wiley & Sons, Ltd.
Fabrication and characterization of an electrostatically bonded PEEK‐ hydroxyapatite composites for biomedical applications
Authors: Baştan Fatih Erdem
Published: February 2020

In this study, it was aimed to produce electrostatically induced polyetheretherketone (PEEK) and strontium substituted hydroxyapatite (SrHA) composites. SrHA nanoparticles (5 and 10 vol%) were introduced in the PEEK matrix to increase its mechanical properties and osseointegration. In order to disperse and homogeneously distribute the nanoparticles within the matrix, an electrostatic bond was developed between the PEEK and nanoparticles by wet processing through the attraction of the oppositely charged particles. Particles were pressed and sintered according to the Taguchi Design of experiments (DoE) array. The effects of SrHA reinforcement, sintering temperature and time on the density, crystallinity and crystallite sizes were determined with density test, DSC and XRD, respectively. The disks were also analyzed via SEM, FTIR, compression, microhardness, and nanoindentation tests and were immersed into the simulated body fluid (SBF). The composites produced from electrostatically induced powders presented a homogenous microstructure as SEM analysis illustrated the homogenous dispersion and distribution of the SrHA nanoparticles. The SrHA nanoparticles decreased the relative density and crystallinity of the composite, whereas, the rise in the sintering temperature and time enhanced the relative density, according to the DoE results. SrHA reinforcement improved the reduced modulus and nanoindentation hardness of the PEEK (348.47 MPa, 5.97 GPa) to 392.02 MPa and 6.65 GPa, respectively. SrHA promoted the bioactivity of the composite: an apatite layer covered the surface of PEEK/10SrHA composite after 14 days incubation. These promising results suggest that the electrostatically bonded composite powders would be used to produce homogenous PEEK based bioactive composites.
LncRNA MST1P2/miR‐133b axis affects the chemoresistance of bladder cancer to cisplatin‐based therapy via Sirt1/p53 signaling
Authors: Chen Jia , Li Yuanwei , Li Zhiqiu , Cao Lin
Published: February 2020

Although bladder cancer is commonly chemosensitive to standard first‐line therapy, the acquisition of the resistance to cisplatin (DDP)‐based therapeutic regimens remains a huge challenge. Noncoding RNAs (ncRNAs), including long noncoding RNAs (lncRNAs) and microRNAs, have been reported to play a critical role in cancer resistance to DDP. Here, we attempted to provide a novel mechanism by which the resistance of bladder cancer to DDP treatment could be modulated from the perspective of ncRNA regulation. We demonstrated that lncRNA MST1P2 (lnc‐MST1P2) expression was dramatically upregulated, whereas miR‐133b expression was downregulated in DDP‐resistant bladder cancer cell lines, SW 780/DDP and RT4/DDP. Lnc‐MST1P2 and miR‐133b negatively regulated each other via targeting miR‐133b. Both lnc‐MST1P2 silence and miR‐133b overexpression could resensitize DDP‐resistant bladder cancer cells to DDP treatment. More important, miR‐133b could directly target the Sirt1 3′‐untranslated region to inhibit its expression. Inc‐MST1P2/miR‐133b axis affected the resistance of bladder cancer cells to DDP via Sirt1/p53 signaling. In conclusion, MST1P2 serves as a competing endogenous RNA for miR‐133b to counteract miR‐133b‐induced suppression on Sirt1, therefore enhancing the resistance of bladder cancer cells to DDP. MST1P2/miR‐133b axis affects the resistance of bladder cancer cells to DDP via downstream Sirt1/p53 signaling.
KIF18B promotes hepatocellular carcinoma progression through activating Wnt/β‐catenin‐signaling pathway
Authors: Yang Bin , Wang Shengzhi , Xie Hui , Wang Chunping , Gao Xudong , Rong Yihui , Liu Zhenwen , Lu Yinying
Published: February 2020

This study aimed to investigate the functional roles of kinesin family member 18B (KIF18B) in hepatocellular carcinoma (HCC) development, as well as the related molecular mechanisms. Tissue specimens were collected from 105 patients with HCC, and the messenger RNA (mRNA) and protein levels of KIF18B were detected using quantitative real‐time polymerase chain reaction and immunohistochemistry assays, respectively. The χ2 test was performed to estimate the association of KIF18B with clinical characteristics of patients with HCC. Effects of KIF18B expression on biological behaviors of HCC cells were detected by clone formation, 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide, and transwell assays. The expression patterns of proteins were investigated using Western blot analysis. HCC tissues and cell lines showed significant upregulation of KIF18B at both mRNA and protein levels (p > .05, for all). Furthermore, the elevated KIF18B expression was positively correlated with the tumor‐node‐metastasis stage (p = .015) and lymph node metastasis (p = .007). Knockdown of KIF18B might suppress HCC cell clone formation, proliferation, migration, and invasion in vitro. Besides, the activity of Wnt/β‐catenin pathway was also significantly inhibited after the KIF18B knockdown. However, the antitumor actions caused by KIF18B knockdown might be reversed by lithium chloride treatment, which was the inducer of Wnt/β‐catenin‐signaling pathway. KIF18B may serve as an oncogene in HCC through enhancing the activity of Wnt/β‐catenin pathway.
miR‐129‐5p inhibits proliferation, migration, and invasion in rectal adenocarcinoma cells through targeting E2F7
Authors: Wan Ping , Bai Xuan , Yang Chao , He Tian , Luo Lilin , Wang Yun , Fan Minmin , Wang Zhilin , Lu Liming , Yin Yajing , Li Sisi , Guo Qiang , Song Zhengyi
Published: February 2020

microRNAs (miRNAs), a kind of small noncoding RNAs, are considered able to regulate expression of genes and mediate RNA silencing. miR‐129‐5p was shown to be a cancer‐related miRNA. However, the influence of miR‐129‐5p in rectal adenocarcinoma (READ) development remains to be determined. Based on the TCGA data, downregulation of miR‐129‐5p in READ samples was observed. Manual restoration of the miR‐129‐5p in SW1463 and SW480 cell lines significantly inhibited invasion, migration, and proliferation of READ cell lines, while the apoptosis ability was enhanced. Meanwhile, we found E2F7 acted as a potential target of miR‐129‐5p and was upregulated in READ samples. E2F7 upregulation reversed the repression of miR‐129‐5p on READ development. Finally, in vivo experiments showed that inhibition of tumor growth in nude mice was achieved through upregulating miR‐129‐5p. Overall, our findings suggest increasing of miR‐129‐5p leads to the suppression of READ progression through regulating the expression of E2F7, which may provide novel insights into the treatment of READ.
Contributions and prognostic values of m6A RNA methylation regulators in non‐small‐cell lung cancer
Authors: Liu Yang , Guo Xiuchen , Zhao Meng , Ao Haijiao , Leng Xue , Liu Mingdong , Wu Caixia , Ma Jianqun , Zhu Jinhong
Published: February 2020

N6‐methyladenosine (m6A) RNA modification can alter gene expression and function by regulating RNA splicing, stability, translocation, and translation. Deregulation of m6A has been involved in various types of cancer. However, its implications in non‐small‐cell lung cancer (NSCLC) are mostly unknown. This posttranscriptional modification is dynamically and reversibly mediated by different regulators, including methyltransferase, demethylases, and m6A binding proteins. In this study, we comprehensively investigated the contributions and prognostic values of 13 common m6A RNA modification regulators using The Cancer Genome Atlas database. We found that the expression levels of most of the studied genes were significantly altered in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). Using consensus clustering, the gene‐expression profiles of 13 m6A regulators could classify patients with LUAD into two subgroups with significantly distinct clinical outcomes, but not the LUSC cohort or the combination of the two cohorts. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and gene set enrichment analysis were applied to explore differential signaling pathways and cellular processes between the two LUAD subgroups. Moreover, we found that this gene‐expression signature could better predict prognosis in the late‐stage (III + IV) than in the early‐stage (I + II) LUAD. Finally, we developed an optimal prognostic gene signature by using the least absolute shrinkage and selection operator Cox regression algorithm and compute risk score. In conclusion, our study unveiled the implication of m6A RNA modification regulators in NSCLC and identified the m6A gene expression classifiers for predicting the prognosis of NSCLC.
miR‐125b lowers sensitivity to apoptosis following mitotic arrest: Implications for breast cancer therapy
Authors: Matuszyk Janusz , Klopotowska Dagmara
Published: February 2020

The process of apoptosis begins when the balance between proapoptotic and antiapoptotic stimuli is disturbed, leading to oligomerization of apoptosis effectors and disruption of the outer mitochondrial membrane. BCL‐2 family proteins are the major regulators of mitochondrial pathway of apoptosis. In turn, microRNA‐125b (miR‐125b) is a member of microRNAs, which are short single‐stranded noncoding RNAs that negatively regulate gene expression at the posttranscriptional level. miR‐125b targets messenger RNAs encoding proapoptotic (BAK1, PUMA, BMF) and antiapoptotic (MCL1) BCL‐2 family proteins. This mini‐review briefly describes the involvement of BCL‐2 family proteins in triggering apoptosis. Then, attention is paid to the differences in the activation of apoptosis with doxorubicin and paclitaxel, and finally the effect of miR‐125b on paclitaxel‐ and doxorubicin‐induced apoptosis in breast cancer cells is considered. It appears that miR‐125b downregulates proteins that are significantly involved in the activation of apoptosis after paclitaxel‐induced prolonged mitotic arrest or subsequent DNA damage if mitotic slippage occurs. It seems that high levels of miR‐125b may not favor paclitaxel therapy, but reduction of miR‐125b levels may increase paclitaxel‐induced apoptosis, possibly also genotoxic‐induced apoptosis, although adverse effects may also occur including decrease in doxorubicin‐induced apoptosis.
M2 differentiation of MonoMac‐1 cell line induced by M‐CSF and glucocorticoid pathways
Authors: Vakili Sarah , Fischer Tracy , Rappaport Jay
Published: February 2020

Models of macrophage subtypes require molecular characterization to reliably facilitate their differentiation. Although CD16+ (Fc‐gamma III receptor) monocytes that express CD163 (a hemoglobin/haptoglobin receptor) have been implicated in a variety of disease states, the conditions necessary to establish lineages of these cell subtypes remains unknown. The current investigations utilize a cell line derived from acute myelogenous leukemia lineage, MonoMac‐1, to interrogate the factors that promote the development of CD16+ macrophages that express CD163. Results implicate the glucocorticoid pathway as well as c‐fms signaling based on the action of dexamethasone and macrophage colony‐stimulating factor‐1 in promoting CD16+ expression, in addition to phorbol myristate acetate and lipopolysaccharides treatment. The ability of glucocorticoid and c‐fms receptor antagonists to inhibit CD16+ cell formation further establishes the role of these pathways in CD16 expression in this cell line. In view of the inherent difficulty in working with primary cells as well as donor variation, cell lines may be preferable to primary cells for their consistency. We envision that the process we use to induce CD16 expression in this cell type will be useful for screening and identification of drug candidates potentially useful for the treatment of diseases where the etiology involves the expansion of the CD16+ monocytes subset or the accumulation of CD163+ tissue macrophages.
KIAA1429 regulates cell proliferation by targeting c‐Jun messenger RNA directly in gastric cancer
Authors: Miao Ran , Dai Cong‐Cong , Mei Lin , Xu Jun , Sun Shan‐Wen , Xing Yun‐Long , Wu Li‐Sheng , Wang Ming‐Hai , Wei Ji‐Fu
Published: February 2020

N6‐methyladenosine (m6A) modification regulatory proteins are involved in the development of many types of cancer. KIAA1429 serves as a scaffold in bridging the catalytic core components of the m6A methyltransferase complex. The role of KIAA1429 in gastric cancer and its related mechanism has not been reported upon. The expression of KIAA1429 was detected in human gastric cancer tissues and cell lines by quantitative real‐time polymerase chain reaction and western blot. The effects of KIAA1429 on gastric cancer proliferation were evaluated by cell counting kit assays, colony formation assays, flow cytometry assay, and in vivo experiments with nude mice. And messenger RNA (mRNA) high‐throughput sequencing, RNA immunoprecipitation assay (RIP), luciferase assay, and a rescue experiment were used to identify the relationship between KIAA1429 and its specific targeted gene, c‐Jun. We found that KIAA1429 was upregulated in gastric cancer tissues, and expressed lower in adjacent tissues. The upregulated KIAA1429 promoted proliferation and downregulated KIAA1429 was proved to inhibit proliferation of gastric cancer in vitro and in vivo. Then, we identified the potential KIAA1429 regulating gene as c‐Jun by mRNAs high‐throughput sequencing and RIP assay. By luciferase assay, we verified that KIAA1429 regulated the expression of c‐Jun in an m6A‐independent manner. Finally, the overexpression of c‐Jun rescued the inhibition of proliferation caused by KIAA1429 knockdown in gastric cancer cells. KIAA1429 could act as an oncogene in gastric cancer by stabilizing c‐Jun mRNA in an m6A‐independent manner. This highlights the functional role for KIAA1429 as a potential prognostic biomarker and therapeutic target in gastric cancer.
Pharmacokinetics, Safety, and Tolerability of Orally Administered Ursodeoxycholic Acid in Patients With Parkinson's Disease—A Pilot Study
Authors: Sathe Abhishek G. , Tuite Paul , Chen Chi , Ma Yiwei , Chen Wei , Cloyd James , Low Walter C. , Steer Clifford J. , Lee Byeong‐Yeul , Zhu Xiao‐Hong , Coles Lisa D.
Published: February 2020

Mitochondrial dysfunction is implicated in the pathogenesis of Parkinson's disease. Preliminary data have shown lower brain adenosine triphosphate (ATP) levels in Parkinson's disease versus age‐matched healthy controls. Ursodeoxycholic acid (UDCA) may improve impaired mitochondrial function. Our objective was to evaluate UDCA tolerability, pharmacokinetics, and its effect on brain bioenergetics in individuals with Parkinson's disease. An open‐label, prospective, multiple‐ascending‐dose study of oral UDCA in 5 individuals with Parkinson's disease was completed. A blood safety panel, plasma concentrations of UDCA and UDCA conjugates, and brain ATP levels were measured before and after therapy (week 1: 15 mg/kg/day; week 2: 30 mg/kg/day; and weeks 3‐6: 50 mg/kg/day). UDCA and conjugates were measured using liquid chromatography–mass spectrometry. ATP levels and ATPase activity were measured using 7‐Tesla 31P magnetic resonance spectroscopy. Secondary measures included the Unified Parkinson's Disease Rating Scale and Montreal Cognitive Assessment. UDCA was generally well tolerated. The most frequent adverse event was gastrointestinal discomfort, rated by subjects as mild to moderate. Noncompartmental pharmacokinetic analysis resulted in (mean ± standard deviation) a maximum concentration of 8749 ± 2840 ng/mL and half‐life of 2.1 ± 0.71 hr. Magnetic resonance spectroscopy data were obtained in 3 individuals with Parkinson's disease and showed modest increases in ATP and decreases in ATPase activity. Changes in Unified Parkinson's Disease Rating Scale (parts I‐IV) and Montreal Cognitive Assessment scores (mean ± standard deviation) were –4.6 ± 6.4 and 2 ± 1.7, respectively. This is the first report of UDCA use in individuals with Parkinson's disease. Its pharmacokinetics are variable, and at high doses it appears reasonably well tolerated. Our findings warrant additional studies of its effect on brain bioenergetics.
Temperature and freezing effects on phosphorus release from soils to overlying floodwater under flooded‐anaerobic conditions
Authors: Kumaragamage Darshani , Concepcion Angela , Gregory Carolyn , Goltz Doug , Indraratne Srimathie , Amarawansha Geethani
Published: February 2020

Increased phosphorus (P) availability under flooded, anaerobic conditions may accelerate P loss from soils to water bodies. Existing knowledge on P release to floodwater from flooded soils is limited to summer conditions and/or room temperatures. Spring snowmelt runoff, which occurs under cold temperatures with frequent freeze–thaw events, is the dominant mode of P loss from agricultural lands to water bodies in the Canadian Prairies. This research examined the effects of temperature on P dynamics under flooded conditions in a laboratory study using five agricultural soils from Manitoba, Canada. The treatments were (a) freezing for 1 wk at −20 °C, thawing and flooding at 4 ± 1 °C (frozen, cold); (b) flooding unfrozen soil at 4 ± 1 °C (unfrozen, cold); and (c) flooding unfrozen soil at 20 ± 2 °C (warm). Pore water and surface water were collected weekly over 8 wk and analyzed for dissolved reactive phosphorus (DRP), pH, calcium, magnesium, iron (Fe), and manganese (Mn). Soils under warm flooding showed enhanced P release with significantly higher DRP concentrations in pore and surface floodwater compared with cold flooding of frozen and unfrozen soils. The development of anaerobic conditions was slow under cold flooding with only a slight decrease in Eh, whereas under warm flooding Eh declined sharply, favoring reductive dissolution reactions releasing P, Fe, and Mn. Pore water and floodwater DRP concentrations were similar between frozen and unfrozen soil under cold flooding, suggesting that one freeze–thaw event prior to flooding had minimal effect on P release under simulated snowmelt conditions.
Remote sensing estimation of the soil erosion cover‐management factor for China's Loess Plateau
Authors: Yang Xihua , Zhang Xiaoping , Lv Du , Yin Shuiqing , Zhang Mingxi , Zhu Qinggaozi , Yu Qiang , Liu Baoyuan
Published: February 2020

The cover‐management factor (C‐factor) is used in the revised universal soil loss equation to represent the effect of vegetation cover and its management practices on hillslope erosion. Remote sensing has been widely used to estimate vegetation cover and the C‐factor, but most previous studies only used the photosynthetic vegetation (PV) or green vegetation indices (VI, e.g., normalized difference VI) for estimating the C‐factor and the important non‐PV (NPV) component was often ignored. In this study, we developed a new technique to estimate monthly time‐series C‐factor using the fractional vegetation cover (FVC) including both PV and NPV, and weighted by monthly rainfall erosivity ratio. The monthly FVC was derived from the moderate resolution imaging spectroradiometer and LANDSAT data with field validation. We conducted the case‐study over China's Loess Plateau and analysed the spatiotemporal variations of FVC and the C‐factor and their impacts on erosion over the Plateau. Our study reveals a significant increase in total vegetation cover (TC) from 56 to 76.8%, with a mean of 71.2%, resulting in about 20% decrease in the C‐factor and erosion risk during the 17‐year period. Our method has an advantage in estimating the C‐factor from TC at a monthly scale providing a basis for continuously and consistently monitoring of vegetation cover, erosion risk and climate impacts.
Activated Platelet‐Derived Vesicles for Efficient Hemostatic Activity
Authors: Lee Joo Hang , Jung Heesun , Song Jihyeon , Choi Eun Seo , You Gayeon , Mok Hyejung
Published: February 2020

In this study, activated platelet‐derived vesicles (Act‐VEs) are developed as a novel hemostatic biomaterial. Spherical Act‐VEs (114.40 ± 11.69 nm in size) with surface charges of −24.73 ± 1.32 mV are successfully prepared from thrombin‐activated murine platelets with high surface expression of active glycoprotein IIb/IIIa (GP IIb/IIIa, also known as αIIbβ3) and P‐selectin. Although nanosized vesicles from resting platelets (VEs) and Act‐VEs showed similar sizes and surface charges, Act‐VEs formed much larger aggregates in the presence of thrombin and CaCl2, compared to VEs. After incubation with fibrinogen, Act‐VEs formed much denser fibrin networks compared to platelets or VEs, probably due to active αIIbβ3 on the surfaces of the Act‐VEs. After intravenous injection of the Act‐VEs, tail bleeding time and the blood loss are greatly reduced by Act‐VEs in vivo. In addition, Act‐VEs showed approximately sevenfold lower release of pro‐inflammatory interleukin‐1β (IL‐1β) during incubation for 4 days, compared to platelets. Taken together, the formulated Act‐VEs can serve as a promising hemostatic biomaterial for the efficient formation of fibrin clots without releasing pro‐inflammatory cytokine.
Supersoft, Stretchable, Tough, and Adhesive Elastomers with Dual Metal‐Ionic Crosslinked Double‐Network Structure
Authors: Jiang Chuanxia , Mai Yuliang , Li Weihao , Liao Bing
Published: February 2020

Soft, stretchable, tough, and adhesive elastomers are developed based on the metal‐ionic crosslinked double network structure, where the metal ion coordination of sulfonated poly(phenylene oxide) (SPPO) is used for the first network and the soft chemical crosslinked poly(ethyl acrylate) (PEA) is used for the second network. The influence of SPPO content on the tensile, cyclic tensile, adhesive, and rheological behavior of the elastomers is systematically investigated. It is observed that the elastomers are immensely soft and stretchable with tunable modulus from 0.038 to 0.086 MPa, fracture strain of ≈1400%, fracture stress in the range 0.20–1.2 MPa, work of extension of 0.72–5.6 MJ m−3, fast self‐recovery of 5 s after experiencing 200% strain, and robust adhesive behavior on glass substrates with interface debonding energy ≈35.2 J m−2. The mechanical behavior of the double‐network elastomers at the macroscopic scale is related to the dynamic breaking and reforming of the metal‐ion coordination at the molecular scale in the first network. This study provides a facile approach for the synthesis of elastomers with multidimensional mechanical behavior and broadens the applications of the elastomers in the field of flexible electronic devices, soft robotics, among others.
Conjugated Polymer Nanoparticles as Unique Coinitiator‐Free, Water‐Soluble, Visible‐Light Photoinitiators of Vinyl Polymerization
Authors: Gallastegui Antonela , Spada Ramiro M. , Cagnetta Gonzalo , Ponzio Rodrigo A. , Martínez Sol R. , Previtali Carlos M. , Gómez María Lorena , Palacios Rodrigo E. , Chesta Carlos A.
Published: February 2020

The use of conjugated polymer nanoparticles (CP NPs) of poly(9,9‐dioctylfluorene‐alt‐benzothiadiazole) and poly(9,9‐di‐n‐octylfluorenyl‐2,7‐diyl) as efficient photoinitiator systems (PIS) of vinyl polymerization in water is reported herein. CP NPs are biocompatible, excitable with blue commercial LEDs and, unlike visible light Type II PIS, do not need co‐initiators to trigger a monomer chain reaction. CP NPs photoinitiate polymerization of a variety of acrylic monomers with initiation rates comparable to those observed for well‐known Type II PIS. Given the extraordinarily large molar absorption coefficients of CP NPs (≈108 m‐1 cm‐1) very low particle concentration is required for effective polymerization. Additionally, CP NPs behave as conventional macrophotoinitiators significantly reducing contamination risks due to leaching of low molecular weight byproducts. These combined features make CP NPs PIS suitable to synthesize polymeric materials for many healthcare and biomedical applications including drug delivery, tissue engineering, prosthetic implants, and food/medicine packaging. These CP NPs PIS are also used to synthesize nano‐hydrogels with a relatively narrow and controlled size distribution in the absence of surfactants. It is proposed that polymerization is initiated at the CP NPs surface by photogenerated free polarons, in close analogy to the mechanism previously described for PIS based on inorganic semiconductor NPs.
Impact of Residual Drug in the Pharynx on the Delayed‐On Phenomenon in Parkinson's Disease Patients
Authors: Fukae Jiro , Fujioka Shinsuke , Umemoto George , Arahata Hajime , Yanamoto Shosaburo , Mishima Takayasu , Tsuboi Yoshio
Published: February 2020

Background and Objective

The delayed‐on phenomenon (DOP) related to levodopa treatment frequently disturbs quality of life in advanced‐stage Parkinson's disease (PD) patients. The objective of this study was to explore the impact of swallowing dysfunction on the development of DOP.

Methods

Swallowing function was investigated by endoscopic evaluation in 11 PD patients with the DOP and 9 PD patients without the DOP during the on phase. Residual drug in the pharynx after taking the drug in tablet, capsule, and powder forms was also observed.

Results

Residual drug was seen in the pharynx in six cases (30.0%). Pooling of saliva, delayed swallowing reflex, and residual drug were more frequent in the DOP group than in the group without the DOP (P < 0.05). The odds ratios for residual drug in the pharynx, pooling of saliva, and delayed swallowing reflex for the DOP were 42.7 (95% confidence interval, 1.89–962.9), 14.0 (95% confidence interval, 1.25–156.6), and 15.8 (95% confidence interval, 1.75–141.4), respectively.

Conclusions

These results suggest that swallowing dysfunction leading to residual antiparkinsonian drug in the pharynx has substantial impacts on the DOP in PD patients.
Improved susceptibility‐weighted imaging for high contrast and resolution thalamic nuclei mapping at 7T
Authors: Jorge João , Gretsch Frédéric , Najdenovska Elena , Tuleasca Constantin , Levivier Marc , Maeder Philippe , Gallichan Daniel , Marques José P. , Bach Cuadra Meritxell
Published: February 2020

Purpose

The thalamus is an important brain structure and neurosurgical target, but its constituting nuclei are challenging to image non‐invasively. Recently, susceptibility‐weighted imaging (SWI) at ultra‐high field has shown promising capabilities for thalamic nuclei mapping. In this work, several methodological improvements were explored to enhance SWI quality and contrast, and specifically its ability for thalamic imaging.

Methods

High‐resolution SWI was performed at 7T in healthy participants, and the following techniques were applied: (a) monitoring and retrospective correction of head motion and B0 perturbations using integrated MR navigators, (b) segmentation and removal of venous vessels on the SWI data using vessel enhancement filtering, and (c) contrast enhancement by tuning the parameters of the SWI phase‐magnitude combination. The resulting improvements were evaluated with quantitative metrics of image quality, and by comparison to anatomo‐histological thalamic atlases.

Results

Even with sub‐millimeter motion and natural breathing, motion and field correction produced clear improvements in both magnitude and phase data quality (76% and 41%, respectively). The improvements were stronger in cases of larger motion/field deviations, mitigating the dependence of image quality on subject performance. Optimizing the SWI phase‐magnitude combination yielded substantial improvements in image contrast, particularly in the thalamus, well beyond previously reported SWI results. The atlas comparisons provided compelling evidence of anatomical correspondence between SWI features and several thalamic nuclei, for example, the ventral intermediate nucleus. Vein detection performed favorably inside the thalamus, and vein removal further improved visualization.

Conclusion

Altogether, the proposed developments substantially improve high‐resolution SWI, particularly for thalamic nuclei imaging.
Direct diazotization of graphite nanoplatelets with melamine and their favorable application in epoxy resins
Authors: Qin Jianyu , Zhang Wenchao , Yang Rongjie
Published: February 2020

The ease of undesirable agglomeration and a low efficiency are two problems that restrict the application of graphite nanoplatelets (GNPs) in epoxy resins (EP). Herein, a new strategy with melamine (MEL) as the precursor to functionalize GNPs chemically, which form a bonding layer that is compatible with epoxy matrix, is reported. The MEL fragments with secondary amine groups were grafted uniformly on the GNPs surface by covalent junctions to exploit the diazonium chemistry. This behavior led to a better dispersion and a stronger interaction with the epoxy matrix and resulted in an enhanced glass transition temperature and bending strength, compared with the pure EP. When only 1 wt% functionalized GNPs (f‐GNPs) was used, the Tg of the modified EP raised of about 15°C compared with pure EP, and the bending strength increased by approximately 39%. The dielectric constant of the EP with f‐GNPs was impacted slightly, and the dielectric loss decreased. At 105 Hz, the dielectric loss of the EP with 1 wt% f‐GNPs decreased by approximately 11% compared with pure EP. Therefore, diazotization modification of the GNPs is a useful approach to improve the compatibility in nanoparticle networks.
Secure attachments predict prosocial behaviors: A moderated mediation study
Authors: Shi Xiaoxuan , Wang Beiyi , He Tingting , Wu Lili , Zhang Jianxin
Published: February 2020

Previous research has shown that secure attachment promotes prosocial behavior. However, the mechanism underlying the link between attachment and prosocial behavior has received relatively little attention. The current study examined the mechanism underlying the link between attachment and prosocial behavior by specifically focusing on the potential mediating role of moral disengagement and whether this mediation effect is moderated by moral identity. Self‐report questionnaires designed to measure attachment, moral identity, moral disengagement, and prosocial behavior were administered to Chinese students (n = 395; 250 females; Mage = 23.38 years). Results showed that secure attachment (maternal attachment, paternal attachment, and peer attachment) was associated with prosocial behavior. In addition, moral disengagement was found to mediate the association between secure attachment and prosocial behavior. Moreover, the mediation effect was moderated by moral identity; specifically, the mediation effect was stronger for individuals with a high level of moral identity than their low‐level moral identity counterparts. The present results suggest that morality could explain the association between attachment and prosocial behaviors.
Recent advances in neuromodulation for spinal cord injuries
Authors: Gaber Tarek , Brown Mary
Published: February 2020

Neuromodulation can be defined as the alteration of nerve activity through targeted delivery of a stimulus that is usually electrical or magnetic. When directed towards peripheral nerves, neuromodulation aims to mimic normal function of efferent nerves. Several methods of neuromodulation are used to elicit an effect, and this evolving therapeutic technique may hold out hope for people with spinal cord injury (SCI), especially if it can be implemented early.
Indefinitely active aqueous cationic polymerizations, part I: Low cost, recyclable initiator systems
Authors: Lewis Stewart P. , Richards Jeffrey A. , Damodaran Krishnan
Published: February 2020

This article describes the first example of an aqueous cationic polymerization that utilizes a low cost, safe, and highly recyclable initiator system (phosphotungstic acid) that retains its activity indefinitely. Quantitative yields of low to medium molecular weight polymers of p‐methoxystyrene and N‐vinylcarbazole are obtained within minutes to hours. Polymerization is first order in both monomer and phosphotungstic acid. Negatively charged surfactants suppress polymerization; whereas, nonionic soaps increase the reaction rate and reduce both polymer molecular weight and polydispersity index. Herein, the discovery of a new form of aqueous cationic polymerization involving the condensation of the alcoholic derivative of p‐methoxystyrene, 1‐(4‐methoxyphenyl)ethanol, is also disclosed.
Investigation of the swelling behavior of hydrogels derived from high‐molecular‐weight poly(2‐ethyl‐2‐oxazoline)
Authors: Segiet Dominik , Jerusalem Robert , Katzenberg Frank , Tiller Joerg C.
Published: February 2020

Thermoresponsive hydrogels are of great importance as smart materials. They are usually composed of cross‐linked polymers with a lower critical solution temperature (LCST). Although much is known about networks of poly(N‐isopropylacrylamide), all other polymers are somewhat neglected. In this work, the temperature‐dependent swelling behavior of differently cross‐linked thermoresponsive poly(2‐ethyl‐2‐oxazoline) (PEtOx) hydrogels were investigated with regard to varying parameters of the network composition. It was found that the degrees of swelling of the hydrogels converge for a certain polymer/solvent system at a distinct temperature independent of its degree of cross‐linking. Furthermore, this temperature correlates with the LCST of the respective starting PEtOx. Its net chain molecular weight Mc only affects the maximum degree of swelling and thus, the swelling–deswelling rate of the hydrogel. The fundamental structure/property relations found in this study could be useful to predict the behavior of other thermoresponsive hydrogels.
Outstanding Photocurrent Density and Incident Photon‐to‐Current Conversion Efficiency of Liquid‐State NiO Perovskite‐Sensitized Solar Cells
Authors: Alessa Hussain , Noh Mohamad Firdaus Mohamad , Mumthas Inzamam Nawas Nawas , Wijayantha Kahagala Gamage Upul , Teridi Mohd Asri Mat
Published: February 2020

The efficiency and photocurrent density reported for p‐type‐sensitized solar cells up to now are still lagging behind that of the n‐type counterparts, limiting the successful development of p–n tandem cells. To circumvent this issue, NiO thin film is fabricated by the aerosol‐assisted chemical vapor deposition (AACVD) technique and used in p‐type solar cells. A systematic study is conducted to comprehend the correlation between NiO thickness and the power conversion efficiency (PCE) of liquid‐state NiO‐based sensitized solar cells. By carefully designing the cell components, this type of device demonstrates the highest photocurrent density (Jsc) exceeding 18 mA cm−2 when using iodine/triiodide as the redox shuttle matching the one produced by the TiO2 counterpart. This is accomplished by 1) using the AACVD technique for the one‐step deposition of compact and mesoporous NiO electrodes, 2) optimizing the thickness of the NiO layer through controlling the deposition time, and 3) adopting methylammonium lead iodide (CH3NH3PbI3) as a light harvester prepared via a sequential deposition method.
Strain Recovery and Defect Characterization in Mg‐Implanted Homoepitaxial GaN on High‐Quality GaN Substrates
Authors: Wang Yekan , Huynh Kenny , Liao Michael E. , Yu Hsuan-Ming , Bai Tingyu , Tweedie James , Breckenridge Mathew Hayden , Collazo Ramon , Sitar Zlatko , Bockowski Michal , Liu Yuzi , Goorsky Mark S.
Published: February 2020

The evolution of defects due to high‐pressure annealing of magnesium ion‐implanted epitaxial GaN grown on high‐quality GaN substrates is investigated. Changes in the implant‐induced strain are quantified as a function of annealing temperature and time. After annealing at 1300 °C for 10 min, the implant‐induced strain is fully relieved and accompanied by the presence of extended defects such as basal plane stacking faults and prismatic loops. Approximately one‐third of the original implant‐induced strain remains after annealing at 700 °C, and 5% of the original strain remains at 1000 °C for 100 min. In all cases, nearly all of the recovered strain occurs within first few minutes of annealing. A prominent increase in the asymmetric (104) triple axis X‐ray rocking curve full width at 0.01 maximum (FW0.01M) is observed after annealing at 1300 °C for 10 min. After annealing at 1300 °C for 100 min, a subsequent decrease in FW0.01M is correlated with a reduction of the extended defect density from 4 × 108 to 3 × 107 cm−2, determined through transmission electron microscope (TEM) measurements. Further reduction in the density of the extended defects by optimizing annealing temperature and time is expected to improve the performance of GaN‐based vertical power devices.
A well‐observed polar low analysed with a regional and a global weather‐prediction model
Authors: Stoll Patrick J. , Valkonen Teresa M. , Graversen Rune G. , Noer Gunnar
Published: February 2020

The capability of a regional (AROME‐Arctic) and a global (ECMWF HRES) weather‐prediction model are compared for simulating a well‐observed polar low (PL). This PL developed on 3–4 March 2008 and was measured by dropsondes released from three flights during the IPY‐THORPEX campaign. Validation against these measurements reveals that both models simulate the PL reasonably well. AROME‐Arctic appears to represent the cloud structures and the high local variability more realistically. The high local variability causes standard error statistics to be similar for AROME‐Arctic and ECMWF HRES. A spatial verification technique reveals that AROME‐Arctic has improved skills at small scales for extreme values. However, the error growth of the forecast, especially in the location of the PL, is faster in AROME‐Arctic than in ECMWF HRES. This is likely associated with larger convection‐induced perturbations in the former than the latter model. Additionally, the PL development is analysed. This PL has two stages, an initial baroclinic and a convective mature stage. Sensible heat flux and condensational heat release both contribute to strengthen the initial baroclinic environment. In the mature stage, latent heat release appears to maintain the system. At least two conditions must be met for this stage to develop: (a) the sensible heat flux sufficiently destabilises the local environment around the PL, and (b) sufficient moisture is available for condensational heat release. More than half of the condensed moisture within the system originates from the surroundings. The propagation of the PL is “pulled” towards the area of strongest condensational heating. Finally, the sensitivity of the PL to the sea‐surface temperature is analysed. The maximum near‐surface wind speed connected to the system increases by 1–2 m·s−1 per K of surface warming and a second centre develops in cases of highly increased temperature.
Evaluation of the Quasi‐Biennial Oscillation in global climate models for the SPARC QBO‐initiative
Authors: Bushell A. C. , Anstey J. A. , Butchart N. , Kawatani Y. , Osprey S. M. , Richter J. H. , Serva F. , Braesicke P. , Cagnazzo C. , Chen C.‐C. , Chun H.‐Y. , Garcia R. R. , Gray L. J. , Hamilton K. , Kerzenmacher T. , Kim Y.‐H. , Lott F. , McLandress C. , Naoe H. , Scinocca J. , Smith A. K. , Stockdale T. N. , Versick S. , Watanabe S. , Yoshida K. , Yukimoto S.
Published: February 2020

Quasi‐biennial oscillations (QBOs) in thirteen atmospheric general circulation models forced with both observed and annually repeating sea surface temperatures (SSTs) are evaluated. In most models the QBO period is close to, but shorter than, the observed period of 28 months. Amplitudes are within ±20% of the observed QBO amplitude at 10 hPa, but typically about half of that observed at lower altitudes (50 and 70 hPa). For almost all models, the oscillation's amplitude profile shows an overall upward shift compared to reanalysis and its meridional extent is too narrow. Asymmetry in the duration of eastward and westward phases is reasonably well captured, though not all models replicate the observed slowing of the descending westward shear. Westward phases are generally too weak, and most models have an eastward time mean wind bias throughout the depth of the QBO. The intercycle period variability is realistic and in some models is enhanced in the experiment with observed SSTs compared to the experiment with repeated annual cycle SSTs. Mean periods are also sensitive to this difference between SSTs, but only when parametrized non‐orographic gravity wave (NOGW) sources are coupled to tropospheric parameters and not prescribed with a fixed value. Overall, however, modelled QBOs are very similar whether or not the prescribed SSTs vary interannually. A portrait of the overall ensemble performance is provided by a normalized grading of QBO metrics. To simulate a QBO, all but one model used parametrized NOGWs, which provided the majority of the total wave forcing at altitudes above 70 hPa in most models. Hence the representation of NOGWs either explicitly or through parametrization is still a major uncertainty underlying QBO simulation in these present‐day experiments.
Chennat‐Type Synthesis of 1,4‐Dihydropyridine Derivatives in Water: Role of a Hydrogen‐Bonding Network
Authors: Isomura Shigeki , Anzai Mayu , Kobayashi Chieka , Okuno Yoshinori , Miyamoto Kazunori , Uchiyama Masanobu , Sato Yasuo
Published: February 2020

An environmentally benign Chennat‐type synthesis of 4‐aryl‐1,4‐dihydropyridine‐3,5‐dicarboxylic acid dimethyl esters was achieved by heating aldehyde, methyl propiolate and an amine salt in water. Excess amine salt accelerated the reaction, while stoichiometric amounts of reagents resulted in lower yield. Various 1,4‐dihydropyridine (1,4‐DHP) derivatives, some of which would be difficult to synthesize in organic solvents, could be obtained in up to 74 % isolated yield. The reaction utilizes a hydrogen‐bonding network with water to accelerate hydroxyl group elimination from the reaction intermediate. Free amine and protons in water might be act as a nucleophile and electrophilic catalyst, respectively.
Facile Synthetic Route for Direct Access of Perylenediimide Single Crystals in High Yield through In Situ Crystallization
Authors: Pitchaimani Jayaraman , Kundu Anu , Anthony Savarimuthu Philip , Moon Dohyun , Madhu Vedichi
Published: February 2020

Synthetic protocol for direct growth of perylenediimides (PDIs) single crystals in high yield via temperature‐driven in situ crystallization has been established. Single crystal analysis confirmed the formation of 1D column of PDIs that are stabilized by π‐π stacking and C−H⋅⋅⋅O hydrogen bonding interactions. The influence of reaction temperature on the crystallization, absorption and fluorescence properties of PDIs has been studied.
Simple, Rapid and Sensitive Detection of Phenylarsine Oxide in Drinking Water Using Quartz Crystal Microbalance: A Novel Surface Functionalization Technique
Authors: Keser Kübra , Mıhçıokur Hamdi , Çağrı Soylu Mehmet
Published: February 2020

A simple, inexpensive, rapid and label‐free detection of phenylarsine oxide (PAO) in the field is a significant and unmet need because of its fatally acute and chronic effects on human health. A chemically easy and applicable surface modification procedure can fill this deficiency. In order to determine the cheaper, simpler and rapid surface functionalization technique, gold surface of quartz crystal microbalance (QCM) sensor was modified with ethanol‐dependent (3‐mercaptopropyl)trimethoxysilane (MPS) coating at pH=4.5 first, and then seconder ethanol‐dependent linker layers, which contain (3‐mercaptopropyl)trimethoxysilane (MPS), dimercaprol (BAL) or 2‐mercaptoethanol (ME), were tested at pH=9.0, respectively. QCM measurements were performed to analyze the stability of each layer in deionized water (DIW) and drinking water for both negative control and arsenic detection performance. Among those examined procedures, the procedure with acidic MPS + basic ME resulted in the best stability in aqueous mediums with a frequency change nearly zero and sensitivity with a frequency shift of 180 (±22) Hz for a concentration of 100 ng/mL PAO in DIW. By using the optimum surface functionalization method, the minimum PAO with a concentration of 1 ng/mL in drinking water was measured as a frequency of 33 (±9) Hz. Besides, this surface modification technique can be applied to the more readily available and cheaper sensor platforms, such as impedimetric electrochemical sensors.