bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Representation of the Porosity‐Pressure Relationship in General Subsurface Flow Codes
Authors: Birdsell Daniel T. , Karra Satish , Rajaram Harihar 
Published: January 2018

AbstractThe governing equations for subsurface flow codes in a deformable porous media are derived from the balance of fluid mass and Darcy's equation. One class of these codes, which we call general subsurface flow codes (GSFs), allow for more general constitutive relations for material properties such as porosity, permeability and density. Examples of GSFs include PFLOTRAN, FEHM, TOUGH2, STOMP, and some reservoir simulators such as BOAST. Depending on the constitutive relations used in GSFs, an inconsistency arises between the standard groundwater flow equation and the governing equation of GSFs, and we clarify that the reason for this inconsistency is because the Darcy's equation used in the GSFs should account for the velocity of fluid with respect to solid. Due to lack of awareness of this inconsistency, users of the GSFs tend to use a porosity‐pressure relationship that comes from the standard groundwater flow equation and assumes that the relative velocity is already accounted for. For the Theis problem, we show that using this traditional relationship in the GSFs leads to significantly large errors. We propose an alternate porosity‐pressure relationship that is consistent with the derivation of the governing equations in the GSFs where the solid velocity is not tracked, and show that, with this relationship, the results are more accurate for the Theis problem. The purpose of this note is to make the users and developers of these GSFs aware of this inconsistency and to advocate that the alternate porosity model derived here should be incorporated in GSFs.
Variations in dosimetric distribution and plan complexity with collimator angles in hypofractionated volumetric arc radiotherapy for treating prostate cancer
Authors: Li Ming‐Hsien , Huang Sheng‐Fang , Chang Chih‐Chieh , Lin Jang‐Chun , Tsai Jo‐Ting 
Published: January 2018

AbstractPurposeHypofractionated radiotherapy can reduce treatment durations and produce effects identical to those of conventionally fractionated radiotherapy for treating prostate cancer. Volumetric arc radiotherapy (VMAT) can decrease the treatment machine monitor units (MUs). Previous studies have shown that VMAT with multileaf collimator (MLC) rotation exhibits better target dose distribution. Thus, VMAT with MLC rotation warrants further investigation.Methods and materialsTen patients with prostate cancer were included in this study. The prostate gland and seminal vesicle received 68.75 and 55 Gy, respectively, in 25 fractions. A dual‐arc VMAT plan with a collimator angle of 0° was generated and the same constraints were used to reoptimize VMAT plans with different collimator angles. The conformity index (CI), homogeneity index (HI), gradient index (GI), normalized dose contrast (NDC), MU, and modulation complexity score (MCSV) of the target were analyzed. The dose–volume histogram of the adjacent organs was analyzed. A Wilcoxon signed‐rank test was used to compare different collimator angles.ResultsOptimum values of CI, HI, and MCSV were obtained with a collimator angle of 45°. The optimum values of GI, and NDC were observed with a collimator angle of 0°. In the rectum, the highest values of maximum dose and volume receiving 60 Gy (V60 Gy) were obtained with a collimator angle of 0°, and the lowest value of mean dose (Dmean) was obtained with a collimator angle of 45°. In the bladder, high values of Dmean were obtained with collimator angles of 75° and 90°. In the rectum and bladder, the values of V60 Gy obtained with the other tested angles were not significantly higher than those obtained with an angle of 0°.ConclusionThis study found that MLC rotation affects VMAT plan complexity and dosimetric distribution. A collimator angle of 45° exhibited the optimal values of CI, HI, and MCSv among all the tested collimator angles. Late side effects of the rectum and bladder are associated with high‐dose volumes by previous studies. MLC rotation did not have statistically significantly higher values of V60 Gy in the rectum and bladder than did the 0° angle. We thought a collimator angle of 45° was an optimal angle for the prostate VMAT treatment plan. The findings can serve as a guide for collimator angle selection in prostate hypofractionated VMAT planning.
Optimizing the NIR Fluence Threshold for Nanobubble Generation by Controlled Synthesis of 10–40 nm Hollow Gold Nanoshells
Authors: Ogunyankin Maria O. , Shin Jeong Eun , Lapotko Dmitri O. , Ferry Vivian E. , Zasadzinski Joseph A. 
Published: January 2018

AbstractThe laser fluence to trigger nanobubbles around hollow gold nanoshells (HGN) with near infrared light is examined through systematic modification of HGN size, localized surface plasmon resonance (LSPR), HGN concentration, and surface coverage. Improved temperature control during silver template synthesis provides monodisperse, silver templates as small as 9 nm. 10 nm HGN with <2 nm shell thickness are prepared from these templates with a range of surface plasmon resonances from 600 to 900 nm. The fluence of picosecond near infrared (NIR) pulses to induce transient vapor nanobubbles decreases with HGN size at a fixed LSPR wavelength, unlike solid gold nanoparticles of similar dimensions that require an increased fluence with decreasing size. Nanobubble generation causes the HGN to melt with a blue shift of the LSPR. The nanobubble threshold fluence increases as the irradiation wavelength moves off the nanoshell LSPR. Surface treatment does not influence the threshold fluence. The threshold fluence increases with decreasing HGN concentration, suggesting that light localization through multiple scattering plays a role. The nanobubble threshold to rupture liposomes is four times smaller for 10 nm than for 40 nm HGN at a given LSPR, allowing us to use HGN size, LSPR, laser wavelength and fluence to control nanobubble generation.
Compositionally Graded Absorber for Efficient and Stable Near‐Infrared‐Transparent Perovskite Solar Cells
Authors: Fu Fan , Pisoni Stefano , Weiss Thomas P. , Feurer Thomas , Wäckerlin Aneliia , Fuchs Peter , Nishiwaki Shiro , Zortea Lukas , Tiwari Ayodhya N. , Buecheler Stephan 
Published: January 2018

AbstractCompositional grading has been widely exploited in highly efficient Cu(In,Ga)Se2, CdTe, GaAs, quantum dot solar cells, and this strategy has the potential to improve the performance of emerging perovskite solar cells. However, realizing and maintaining compositionally graded perovskite absorber from solution processing is challenging. Moreover, the operational stability of graded perovskite solar cells under long‐term heat/light soaking has not been demonstrated. In this study, a facile partial ion‐exchange approach is reported to achieve compositionally graded perovskite absorber layers. Incorporating compositional grading improves charge collection and suppresses interface recombination, enabling to fabricate near‐infrared‐transparent perovskite solar cells with power conversion efficiency of 16.8% in substrate configuration, and demonstrate 22.7% tandem efficiency with 3.3% absolute gain when mechanically stacked on a Cu(In,Ga)Se2 bottom cell. Non‐encapsulated graded perovskite device retains over 93% of its initial efficiency after 1000 h operation at maximum power point at 60 °C under equivalent 1 sun illumination. The results open an avenue in exploring partial ion‐exchange to design graded perovskite solar cells with improved efficiency and stability.
Topotactic Engineering of Ultrathin 2D Nonlayered Nickel Selenides for Full Water Electrolysis
Authors: Wu Hao , Lu Xin , Zheng Gengfeng , Ho Ghim Wei 
Published: January 2018

AbstractFabrication of ultrathin 2D nonlayered nanomaterials remains challenging, yet significant due to the new promises in electrochemical functionalities. However, current strategies are largely restricted to intrinsically layered materials. Herein, a combinatorial self‐regulating acid etching and topotactic transformation strategy is developed to unprecedentedly prepare vertically stacked ultrathin 2D nonlayered nickel selenide nanosheets. Due to the inhibited hydrolyzation under acidic conditions, the self‐regulating acid etching results in ultrathin layered nickel hydroxides (two layers). The ultrathin structure allows limited epitaxial extension during selenization, i.e., the nondestructive topotactic transformation, enabling facile artificial engineering of hydroxide foundation frameworks into ultrathin nonlayered selenides. Consequently, the exquisite nonlayered nickel selenide affords high turnover frequencies, electrochemical surface areas, exchange current densities, and low Tafel slopes, as well as facilitating charge transfer toward both oxygen and hydrogen evolution reactions. Thus, the kinetically favorable bifunctional electrocatalyst delivers advanced and robust overall water splitting activities in alkaline intermediates. The integrated methodology may open up a new pathway for designing other highly active 2D nonlayered electrocatalysts.
Skills transfer to sinus surgery via a low‐cost simulation‐based curriculum
Authors: Harbison R. Alex , Dunlap Jennifer , Humphreys Ian M. , Davis Greg E. 
Published: January 2018

BackgroundSurgical skill development outside the operating room aims to improve technique and subsequent patient safety. The purpose of this study was to evaluate the correlation between technical and cognitive skills with cadaveric endoscopic sinus surgery (ESS) performance and change in ESS performance before and after implementation of a dedicated ESS simulation‐based and knowledge‐based curriculum.MethodsA before‐after study design was implemented among 10 medical students and 10 junior otolaryngology residents. Participants completed a knowledge‐based, multiple‐choice ESS pretest and watched an ESS prosection video. Participants performed 9 tasks on a previously validated low‐cost, low‐technology, nonbiologic sinus surgery task trainer followed by cadaveric maxillary antrostomy and anterior ethmoidectomy. Participants then completed a simulation‐based and knowledge‐based ESS curriculum followed by a repeat cadaveric maxillary antrostomy and anterior ethmoidectomy. Performance was graded with a 5‐point global rating scale (GRS) and a 5‐point ESS‐specific checklist.ResultsWe observed a stronger correlation between the multiple‐choice, knowledge‐based, ESS pretest scores and cadaveric ESS GRS score (r = 0.73) than between task trainer performance and cadaveric ESS GRS score (r = 0.43). We also noted a significant increase in precurriculum vs postcurriculum mean ± standard deviation (SD) cadaveric ESS checklist scores for both medical students (1.18 ± 0.25 vs 2.58 ± 0.57; p = 0.0002) and residents (2.09 ± 0.78 vs 2.88 ± 0.54; p = 0.023). The greatest improvements for residents were in performance of uncinectomy, enlargement of maxillary os, and identification of the bulla.ConclusionThese findings provide evidence supporting the use of ESS training curricula outside the operating room.
Catalytic Desymmetrizing Dehydrogenation of 4‐Substituted Cyclohexanones through Enamine Oxidation
Authors: Zhu Lihui , Zhang Long , Luo Sanzhong 
Published: January 2018

AbstractA desymmetrizing dehydrogenation process catalyzed by a chiral primary amine is described herein. The reaction proceeds through the oxidation of a ketone enamine by IBX and enables the highly enantioselective desymmetrization of 4‐substituted cyclohexanones with the generation of chiral 4‐substituted cyclohexenones containing a remote γ‐stereocenter.
Kryptofix 5 as an inexpensive and efficient ligand for the palladium‐catalyzed Mizoroki‐Heck reaction
Authors: Movassagh Barahman , Ranjbari Shabnam 
Published: January 2018

A novel complex of PdCl2 with a multidentate cryptand ligand, Kryptofix 5, has been prepared and characterized by various techniques including 1H‐ and 13C NMR spectroscopy, Fourier transform infrared (FT‐IR), Raman, ultraviolet and visible (UV‐VIS) spectroscopy, inductively coupled plasma (ICP), CHN elemental and energy dispersive X‐ray analysis (EDX). This heat‐ and air‐stable complex was utilized as a highly active catalyst for the Mizoroki‐Heck reaction of aryl halides with various olefins. Interestingly, it was found that aryl bromides as well as aryl iodides were efficiently cross‐coupled with terminal alkenes at 130 °C in 10 min. Furthermore, the least reactive aryl chlorides reacted with styrene to obtain the desired products in acceptable yields.
Cell‐based studies of the first‐in‐class half‐sandwich Ir(III) complex containing histone deacetylase inhibitor 4‐phenylbutyrate
Authors: Štarha Pavel , Trávníček Zdeněk , Drahoš Bohuslav , Herchel Radovan , Dvořák Zdeněk 
Published: January 2018

We report on a cytotoxic half‐sandwich iridium(III) complex [Ir(η5‐Cpph)(phen)(PB)]PF6 (1‐PB), containing a monodentate coordinated O‐donor 4‐phenylbutyrato ligand (PB) belonging to the family of histone deacetylase inhibitors (HDACi); HCpph = (2,3,4,5‐tetramethylcyclopenta‐2,4‐dien‐1‐yl)benzene, phen = 1,​10‐phenanthroline. The solution behaviour studies indicated that complex 1‐PB partially hydrolysed in the mixture of methanol and water (1:4, v/v), resulting in the release of the PB ligand. The extent of the PB ligand release increased in the presence of 2 molar equiv. of the reduced glutathione (GSH). Complex 1‐PB exhibited comparable in vitro cytotoxicity against the cisplatin‐sensitive (IC50 = 15.8 μM) and ‐resistant (IC50 = 13.0 μM) variants of the A2780 human ovarian carcinoma cells, while its potency against the MRC‐5 human normal fibroblast cells was markedly lower (IC50 = 124.1 μM). The cytotoxicity studies revealed an ability of complex 1‐PB to overcome the acquired resistance against cisplatin, with the resistance factor (RF = 0.8) being markedly lower than for complex 1‐Cl (RF = 1.8) and cisplatin (RF = 2.9). The A2780 cell‐based flow cytometry experiments showed different cell cycle modification induced by complex 1‐PB and cisplatin, induction of production of reactive oxygen species, and higher mitochondria membrane potential depleted cell populations after the treatment by complex 1‐PB as compared with cisplatin. In the cell‐free assay, complex 1‐PB inhibited the HDAC activity to ca 66% as compared to ca 74% valid for NaPB. The [Ir(η5‐Cpph)(phen)(H2O)]2+ species (1‐OH2), representing the hydrolysis product of both complexes 1‐PB and 1‐Cl, induced hydroxyl radical from the hydrogen peroxide, as proved by the EPR spin trapping studies with the 5‐(diethoxyphosphoryl)‐5‐methyl‐1‐pyrroline‐N‐oxide (DEPMPO) spin trap.
The colloidal properties of alkaline‐soluble waterborne polymers
Authors: Scheerder Jurgen , Dollekens Remy , Langermans Harm 
Published: January 2018

ABSTRACTWaterborne polymer dispersions are widely used in coatings and graphic arts markets as environmentally friendly and more sustainable alternatives to solvent borne binders. Traditionally, waterborne (meth)acrylic dispersions are prepared by emulsion polymerization using low molar mass surfactants as a key ingredient to control particle size. However, these surfactants can have a negative influence on the performance of coatings such as reduced water resistance and adhesion. To mitigate the negative effects of surfactants, polymer latexes have been developed that employ alkaline‐soluble polymers as the sole stabilizer for a subsequent emulsion polymerization step. In this way surfactant‐free polymer dispersions are obtained. Despite the high commercial impact and relevance of this technology, fundamental studies regarding the physicochemical properties of the alkaline‐soluble polymers are lacking. In this article, the synthesis and colloidal properties of alkaline‐soluble waterborne methacrylic copolymers are reported. The dissolution behavior and colloidal properties of these alkaline‐soluble polymers were studied as function of molar mass, acid content, and pH. The dissolving polymer particles were characterized using static and dynamic light scattering, static and dynamic surface tension measurements, and cryogenic‐transmission electron microscopy analysis. It is concluded that the dissolution mechanism of alkaline‐soluble polymers follows a gradual process. As the pH increases deprotonation of the carboxylic acid groups swells the particle enhancing the further swelling with water. At a certain amount of base, the particles disintegrate into small polymer aggregates while the most water‐soluble polymer chains are dissolved in the water phase. An important learning is that part of the alkaline‐soluble polymer resides in very small particles (<5 nm). The formation of these polymer particles below 5 nm was not reported previously and offers a new insight into the dissolution mechanism of alkaline soluble polymers. The most important parameter steering this process is the acid value of the polymer, while the molar mass plays a modest role. The understanding gained in this study can be used to further advance alkaline‐soluble polymers as stabilizer in surfactant‐free emulsion polymerization technology, improving the performance of a wide range of industrially relevant coatings. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46168.
Molecular characterization and gene silencing of Laccase 1 in the grain aphid, Sitobion avenae
Authors: Zhang Yong , Fan Jia , Francis Frédéric , Chen Julian 
Published: January 2018

AbstractLaccase 1 (Lac1), a polyphenol oxidase, has been proposed to be involved in insect iron metabolism and immunity responses. However, little information is available on the roles of Lac 1 in insect–plant interactions. The grain aphid Sitobion avenae is one of the most destructive pests of cereal, directly drawing phloem sap and transmitting viruses. In the present study, we first cloned the open reading frame (ORF) of Lac 1 from S. avenae, and the putative protein sequence was predicted to have a carboxyl‐terminal transmembrane domain. We found that SaLac1 had higher expression levels in the fourth and adult stages using reverse transcription real‐time quantitative PCR (RT‐qPCR). SaLac 1 was highly expressed in the salivary gland and midgut and also in wingless compared with winged morphs. After feeding on aphid‐resistant wheat with a high total phenol content, the expression level of SaLac 1 increased significantly. RNA interference (RNAi) by oral feeding successfully inhibited the transcript levels of SaLac 1, and the knockdown of Lac 1 significantly decreased the survival rate of S. avenae on aphid‐resistant wheat. Our study demonstrated that S. avenae Lac1 was involved in the detoxification of phenolic compounds in wheat and was essential for the aphid to adapt to resistant plants.
Maternal exposures and risk of oral clefts in South Vietnam
Authors: Dien Vu H. A. , McKinney Christy M. , Pisek Araya , Pitiphat Waranuch 
Published: January 2018

BackgroundOral clefts are among the most common congenital anomalies. Most studies on risk factors of oral clefts have been carried out in developed countries. We investigated the associations between maternal exposures in the first trimester and oral clefts in South Vietnam.MethodsWe conducted a hospital‐based case‐control study during October 2014‐November 2015. Cases included 170 patients with nonsyndromic cleft lip with or without cleft palate and those with cleft palate only. Controls were 170 children without oral clefts, matched to each case by age and gender. Mothers were interviewed using structured questionnaire. We performed conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs).ResultsPassive smoking was associated with increased risk of oral clefts in univariate analysis, but not in multivariable analysis (adjusted OR [aOR] = 1.68; 95% CI, 0.53–5.37). No association was observed between liver intake and oral clefts. Compared with nondrinkers, mothers who reported consumption of caffeine‐containing beverages were more likely to have an infant with oral cleft (aOR = 5.89; 95% CI, 1.08–32.00). Periconceptional use of folic acid and multivitamins supplementation was associated with reduced risk of oral clefts (aOR = 0.01; 95% CI, 0.00–0.09 and aOR = 0.03; 95% CI, 0.01–0.13, respectively).ConclusionsThe results suggest no associations of maternal passive smoking or liver intake with oral clefts. Periconceptional use of folic acid or multivitamins may protect against oral clefts. Further studies are warranted to examine the roles of caffeine consumption in pregnant mothers on occurrence of oral clefts in offspring.
Oral delivery system enhanced the bioavailability of stilbenes: Resveratrol and pterostilbene
Authors: Peng Ru‐Min , Lin Guan‐Ru , Ting Yuwen , Hu Jing‐Yu 
Published: January 2018

AbstractStilbenes are a large group of compounds with the C6C2C6 skeleton, in which two aromatic rings are connected by an ethylene bridge. Resveratrol and its structural analog, pterostilbene, are by far the two most widely researched stilbenes in terms of their beneficial bioactivities. However, the bioefficacy of these compounds is greatly reduced when consumed orally due to their poor aqueous solubility, which leads to poor bioavailability. To overcome the limitation, strategies improving their solubility, absorption, and systemic concentration were applied when designing a suitable edible delivery system. This review will summarize the findings from the studies evaluating the oral bioavailability of stilbenes with emphasize on the resveratrol and pterostilbene. It will also include the edible delivery systems currently available and their effect on the oral bioavailability. © 2018 BioFactors, 44(1):5–15, 2018
3D Printing for Chemical Process Laboratories I: Materials and Connection Principles
Authors: Gelhausen Marius Gerrit , Feuerbach Tim , Schubert Ansgar , Agar David William 
Published: January 2018

AbstractThe fabrication of milliliter‐scale test structures for chemical process laboratories with a low‐cost 3D printer operating according to the principle of fused filament fabrication is evaluated. Different polymers such as polypropylene and poly(vinylidene fluoride) were used and fabrication guidelines are provided. Furthermore, reversible and irreversible concepts for connecting 3D‐printed parts to peripherals or to other additively manufactured parts are described. After fabrication, the structures were tested for gas tightness, which was limited without subsequent finishing due to the layer‐wise fabrication process. However, gas tightness up to 600 kPa was attained by using tools like sealing tape. Finally, the developed concepts were extended to permit the insertion of thermoelements or other metallic probes.
Pentacene Dimers as a Critical Tool for the Investigation of Intramolecular Singlet Fission
Authors: Hetzer Constantin , Guldi Dirk M. , Tykwinski Rik R. 
Published: January 2018

AbstractSinglet fission (SF) involves the spontaneous splitting of a photoexcited singlet state into a pair of triplets, and it holds great promise toward the realization of more efficient solar cells. Although the process of SF has been known since the 1960s, debate regarding the underlying mechanism continues to this day, especially for molecular materials. A number of different chromophores have been synthesized and studied in order to better understand the process of SF. These previous reports have established that pentacene and its derivatives are especially well‐suited for the study of SF, since the energetic requirement E(S1)≥2E(T1) is fulfilled rendering the process exothermic and unidirectional. Dimeric pentacene derivatives, in which individual pentacene chromophores are tethered by a “spacer”, have emerged as the system of choice toward exploring the mechanism of intramolecular singlet fission (iSF). The dimeric structure, and in particular the spacer, allows for controlling and tuning the distance, geometric relationship, and electronic coupling between the two pentacene moieties. This Minireview describes recent advances using pentacene dimers for the investigation of iSF.