bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing clustered sampling designs for spatially explicit estimation of population density
Authors: Clark Joseph D.
Published: January 2019

Spatially explicit capture–recapture methods do not assume that animals have equal access to sampling devices (e.g., detectors), which allows for gaps in the sampling extent and nonuniform (e.g., clustered) sampling designs. However, the performance (i.e., relative root mean squared error [RRMSE], confidence interval coverage, relative bias and relative standard error) of clustered detector arrays has not been thoroughly evaluated. I used simulations to evaluate the performance of various detector and cluster spacings, cluster configurations (i.e., number of detectors arranged in a square grid), sampling extents and number of sampling occasions for estimating population density, the relationship between detection rate and distance to a detector from the animal's center of activity (σ) and base detection rates, using American black bears (Ursus americanus) as a case study. My simulations indicated that a wide range of detector configurations can provide reliable estimates if spacing between detectors in clusters is ≥1σ and ≤3σ. A number of cluster configurations and occasion lengths produced estimates that were unbiased, resulted in good spatial coverage, and were relatively precise. Moreover, increasing the duration of sampling, establishing large study areas, increasing detection rates and spacing clusters so that cross‐cluster sampling of individuals can occur could help ameliorate deficiencies in the detector layout. These results have application for a wide array of species and sampling methods (e.g., DNA sampling, camera trapping, mark‐resight and search‐encounter) and suggest that clustered sampling can significantly reduce the effort necessary to provide reliable estimates of population density across large spatial extents that previously would have been infeasible with nonclustered sampling designs.
Coupled population dynamics of two Neotropical marsupials driven by mesopredator's abundance
Authors: Kuhnen Vanessa V. , Wedekin Leonardo L. , Setz Eleonore Z. F.
Published: January 2019

According to the mesopredator release theory, when top predators are eradicated from an area, mesopredators become overabundant. Didelphis aurita is the largest marsupial in the Atlantic Rainforest, and it occurs in higher abundances in the absence of top predators. This mesopredator has similar ecological requirements to the sympatric marsupial Metachirus nudicaudatus. Considering the similar requirements, and that D. aurita is about three times the size of M. nudicaudatus, our hypothesis is that the increase in D. aurita's abundance may negatively affect M. nudicaudatus' population. To test this hypothesis, we conducted a two‐year capture‐mark‐recapture study in an area in the Southeast of Brazil where top predator community is depauperated. The relationship between the population dynamics of these two marsupials was analyzed by including abundance of D. aurita and environmental conditions as explanatory variables of the population parameters of M. nudicaudatus. We observed that all demographic parameters of M. nudicaudatus fluctuated over time and responded negatively to D. aurita abundance. Our conclusion is that, at least on a monthly timescale, the interspecific relationship with D. aurita seems to influence more M. nudicaudatus' population than any other environmental covariate. These findings suggest that mesopredator release can promote negative effects on population parameters of other species within the same trophic level. Considering that top predators are no longer present in most of the remaining Atlantic Rainforest fragments, the marsupial D. aurita has become a key species in this biome, with relevant consequences arising from its interspecific interactions.
Output factors of ionization chambers and solid state detectors for mobile intraoperative radiotherapy (IORT) accelerator electron beams
Authors: Güngör Görkem , Aydın Gökhan , Mustafayev Teuta Zoto , Özyar Enis
Published: January 2019

Purpose

The electron energy characteristics of mobile intraoperative radiotherapy (IORT) accelerator LIAC® differ from commonly used linear accelerators, thus some of the frequently used detectors can give less accurate results. The aim of this study is to evaluate the output factors (OFs) of several ionization chambers (IC) and solid state detectors (SS) for electron beam energies generated by LIAC® and compare with the output factor of Monte Carlo model (MC) in order to determine the adequate detectors for LIAC®.

Methods

The OFs were measured for 6, 8, 10, and 12 MeV electron energies with PTW 23343 Markus, PTW 34045 Advanced Markus, PTW 34001 Roos, IBA PPC05, IBA PPC40, IBA NACP‐02, PTW 31010 Semiflex, PTW 31021 Semiflex 3D, PTW 31014 Pinpoint, PTW 60017 Diode E, PTW 60018 Diode SRS, SNC Diode EDGE, and PTW 60019 micro Diamond detectors. Ion recombination factors (ksat) of IC were measured for all applicator sizes and OFs were corrected according to ksat. The measured OFs were compared with Monte Carlo output factors (OFMC).

Results

The measured OFs of IBA PPC05, PTW Advanced Markus, PTW Pinpoint, PTW microDiamond, and PTW Diode E detectors are in good agreement with OFMC. The maximum deviations of IBA PPC05 OFs to OFMC are −1.6%, +1.5%, +1.5%, and +2.0%; for PTW Advanced Markus +1.0%, +1.5%, +2.0%, and +2.0%; for PTW Pinpoint +2.0%, +1.6%, +4.0%, and +2.0%; for PTW microDiamond −1.6%, +2%, +1.1%, and +1.0%; and for PTW Diode E −+1.7%, +1.7%, +1.3%, and +2.5% for 6, 8, 10, and 12 MeV, respectively. PTW Roos, PTW Markus, IBA PPC40, PTW Semiflex, PTW Semiflex 3D, SNC Diode Edge measured OFs with a maximum deviation of +5.6%, +4.5%, +5.6%, +8.1%, +4.8%, and +9.6% with respect to OFMC, while PTW Diode SRS and IBA NACP‐02 were the least accurate (with highest deviations −37.1% and −18.0%, respectively).

Conclusion

The OFs results of solid state detectors PTW microDiamond and PTW Diode E as well as the ICs with small electrode spacing distance such as IBA PPC05, PTW Advanced Markus and PTW Pinpoint are in excellent agreement with OFMC. The measurements of the other detectors evaluated in this study are less accurate, thus they should be used with caution. Particularly, PTW Diode SRS and IBA NACP‐02 are not suitable and their use should be avoided in relative dosimetry measurements under high dose per pulsed (DPP) electron beams.
No One's Driving: Autonomous Vehicles Will Reshape Cities, but is Anyone Taking Control of How?
Authors: Maughan Tim
Published: January 2019

Driverless cars promise to be a seductive, inevitable technology that will transform our cities in a multitude of ways. But, asks author and journalist Tim Maughan, are we really prepared for what lies ahead, or have we already fallen asleep at the wheel?
High Performance of T6‐Treated Al–15Mg2Si–3Cu Composite Reinforced with Spherical Primary Mg2Si after the Co‐Modification of Bi + Sr
Authors: Chong Xueying , Jiang Wenqiang , Zhao Yuguang , Xu Xiaofeng , Pan Dong , Wang Yitong , Wang Zhe
Published: January 2019

In this work, the effect of the addition of Bi combined with T6 treatment on microstructure and tensile properties of Sr‐modified Al–15Mg2Si–3Cu composite is investigated. The results show that the refinement effect of Sr on primary Mg2Si is further enhanced via the combined addition of Bi. Interestingly, the truncated octahedral primary Mg2Si with the smallest size (11.5 μm) is obtained by adding 0.1% Sr and 1% Bi, which is distinctly different from the cubic shape modified by single 0.1% Sr. Consequently, as a precursor with strong diffusion of Mg and Si atoms during T6 treatment, the truncated octahedral primary Mg2Si is completely transformed into spherical morphology with the highest sphericity (0.92) solution treated at 500 °C for 6 h. Additionally, further results reveal that the co‐modification of Sr + Bi is more efficient not only in promoting the spheroidization of primary Mg2Si, but also obtaining the fine dot‐like eutectic Mg2Si than single modification of Sr or Bi. As a result, the tensile strength and elongation are significantly enhanced to 374 MPa and 4.75%, respectively. Thereby, this work offers an alternative co‐modification system combined with T6 treatment to synthesize the spherical primary Mg2Si, which is helpful to prepare the high performance Al–Mg2Si composite.
Tunable Graphene Electronics with Local Ultrahigh Pressure
Authors: Ares Pablo , Pisarra Michele , Segovia Pilar , Díaz Cristina , Martín Fernando , Michel Enrique G. , Zamora Félix , Gómez‐Navarro Cristina , Gómez‐Herrero Julio
Published: January 2019

Fine‐tuning of graphene effective doping is achieved by applying ultrahigh pressures (>10 GPa) using atomic force microscopy (AFM) diamond tips. Specific areas in graphene flakes are irreversibly flattened against a SiO2 substrate. This work represents the first demonstration of local creation of very stable effective p‐doped graphene regions with nanometer precision, as unambiguously verified by a battery of techniques. Importantly, the doping strength depends monotonically on the applied pressure, allowing a controlled tuning of graphene electronics. Through this doping effect, ultrahigh pressure modifications include the possibility of selectively modifying graphene areas to improve their electrical contact with metal electrodes, as shown by conductive AFM. Density functional theory calculations and experimental data suggest that this pressure level induces the onset of covalent bonding between graphene and the underlying SiO2 substrate. This work opens a convenient avenue to tuning the electronics of 2D materials and van der Waals heterostructures through pressure with nanometer resolution.
Layer‐by‐Layer Cerium Oxide Nanoparticle Coating for Antioxidant Protection of Encapsulated Beta Cells
Authors: Abuid Nicholas J. , Gattás‐Asfura Kerim M. , Schofield Emily A. , Stabler Cherie L.
Published: January 2019

In type 1 diabetes, the replacement of the destroyed beta cells could restore physiological glucose regulation and eliminate the need for exogenous insulin. Immunoisolation of these foreign cellular transplants via biomaterial encapsulation is widely used to prevent graft rejection. While highly effective in blocking direct cell‐to‐cell contact, nonspecific inflammatory reactions to the implant lead to the overproduction of reactive oxygen species, which contribute to foreign body reaction and encapsulated cell loss. For antioxidant protection, cerium oxide nanoparticles (CONPs) are a self‐renewable, ubiquitous, free radical scavenger currently explored in several biomedical applications. Herein, 2–12 alternating layers of CONP/alginate are assembled onto alginate microbeads containing beta cells using a layer‐by‐layer (LbL) technique. The resulting nanocomposite coatings demonstrate robust antioxidant activity. The degree of cytoprotection correlates with layer number, indicating tunable antioxidant protection. Coating of alginate beads with 12 layers of CONP/alginate provides complete protection to the entrapped beta cells from exposure to 100 × 10−6 m H2O2, with no significant changes in cellular metabolic activity, oxidant capacity, or insulin secretion dynamics, when compared to untreated controls. The flexibility of this LbL method, as well as its nanoscale profile, provides a versatile approach for imparting antioxidant protection to numerous biomedical implants, including beta cell transplantation.
Optically Rewritable Transparent Liquid Crystal Displays Enabled by Light‐Driven Chiral Fluorescent Molecular Switches
Authors: Li Juntao , Bisoyi Hari Krishna , Tian Jiajun , Guo Jinbao , Li Quan
Published: January 2019

Functional soft materials exhibiting distinct functionalities in response to a specific stimulus are highly desirable towards the fabrication of advanced devices with superior dynamic performances. Herein, two novel light‐driven chiral fluorescent molecular switches have been designed and synthesized that are able to exhibit unprecedented reversible Z/E photoisomerization behavior along with tunable fluorescence intensity in both isotropic and anisotropic media. Cholesteric liquid crystals fabricated using these new fluorescent molecular switches as chiral dopants exhibit reversible reflection color tuning spanning the visible and infrared region of the spectrum. Transparent display devices have been fabricated using both low chirality and high chirality cholesteric films that operate either exclusively in fluorescent mode or in both fluorescent and reflection mode, respectively. The dual mode display device employing short pitch cholesteric film is able to function on demand under all ambient light conditions including daylight and darkness with fast response and high resolution. Moreover, the proof‐of‐concept for a “remote‐writing board” using cholesteric films containing one of the light‐driven chiral fluorescent molecular switches with ease of fabrication and operation is disclosed herein. Such optically rewritable transparent display devices enabled by light‐driven chiral fluorescent molecular switches pave a new way for developing novel display technology under different lighting conditions.
Hybrid ZnON–Organic Light Emitting Transistors with Low Threshold Voltage <5 V
Authors: Park Yu Jung , Song AeRan , Walker Bright , Seo Jung Hwa , Chung Kwun‐Bum
Published: January 2019

The electrical and optical properties of inorganic–organic hybrid light emitting transistors (HLETs) are investigated, which are fabricated using the n‐type semiconductor zinc‐oxynitride (ZnON) as an electron transporting layer and the poly(p‐phenylene vinylene)‐based copolymer, Super Yellow (SY), as the light emitting layer. Additionally, the influence of various source (S)–drain (D) electrodes (Al, Ag, and Au) with different work functions (WFs) (4.1, 4.6, and 5.1 eV, respectively) on the performance of HLETs is studied. In order to increase the rate of hole injection from the metal electrodes and increase hole accumulation at the emissive layer, the use of a molybdenum oxide (MoOx) interlayer is also investigated. As a result, optimized devices using MoOx/Au hole injecting electrodes yield high brightness of up to 3.04 × 104 cd∙m−2 at a low threshold voltage of 4.79 V. This study provides valuable information about the role of the WF of S–D electrodes in HLETs, which may be exploited to improve the device performance of optoelectronic devices in the future.
Fluorinated Organic Electro‐Optic Quinolinium Crystals for THz Wave Generation
Authors: Kim Se‐In , Kang Bong Joo , Jeong Chan‐Uk , Shin Myeong‐Hoon , Kim Won Tae , Jazbinsek Mojca , Yoon Woojin , Yun Hoseop , Kim Dongwook , Rotermund Fabian , Kwon O‐Pil
Published: January 2019

Fluorinated electro‐optic crystals with state‐of‐the‐art second‐order nonlinear optical response and excellent characteristics for terahertz (THz) wave generation are reported. The fluorinated organic ionic crystals consist of optically highly nonlinear fluorinated HM6FQ (6‐fluoro‐2‐(4‐hydroxy‐3‐methoxystyryl)‐1‐methylquinolinium) or HM7FQ (7‐fluoro‐2‐(4‐hydroxy‐3‐methoxystyryl)‐1‐methylquinolinium) cations and 4‐methylbenzenesulfonate (T) counter anions. Compared to benchmark electro‐optic crystals based on nonfluorinated HMQ (2‐(4‐hydroxy‐3‐methoxystyryl)‐1‐methylquinolinium) cations, introducing fluorine substituent on HM6FQ cations creates additional hydrogen bonds (ArF···HC). Such a molecular engineering leads to an enhanced thermal stability and significant modulations of phonon vibrational modes of crystals in THz frequency region, while excellent π–π stacking and space filling characteristics of HM6FQ cations in crystals lead to state‐of‐the‐art diagonal component of the macroscopic nonlinear optical susceptibility, similar to the case of HMQ cations. HM6FQ‐based crystals exhibit a very high optical‐to‐THz conversion efficiency, comparable to benchmark HMQ‐based crystals. In addition, due to additional hydrogen bonds induced by fluorine substituents, the spectral shape of the generated THz wave is remarkably modified; e.g., the largest spectral gap is near 1.5 and 2.0 THz for HM6FQ‐ and HMQ‐based crystals, respectively. The fluorinated cationic engineering on nonlinear optical crystals having benchmark nonlinear optical response is, as far as is known, reported for the first time.
Mixing Thermodynamics and Photocatalytic Properties of GaP–ZnS solid solutions
Authors: Shenoy Joel , Hart Judy N. , Grau‐Crespo Ricardo , Allan Neil L. , Cazorla Claudio
Published: January 2019

Preparation of solid solutions represents an effective means to improve the photocatalytic properties of semiconductor‐based materials. Nevertheless, the effects of site‐occupancy disorder on the functional properties of materials are difficult to predict and consequently many experimental trials may be required before achieving enhanced photocatalytic activity. Here, first‐principles methods are employed to estimate the mixing free energy and the structural and electronic properties of (GaP)x (ZnS) solid solutions. The method relies on a multi‐configurational supercell approach that takes into account the configurational and vibrational contributions to the free energy. Phase competition among the zinc‐blende and wurtzite polymorphs is also considered. Overall excellent agreement with the available experimental data is demonstrated, namely: 1) zinc‐blende is energetically most favorable, 2) the solid solution energy band gap lies within the 2–3 eV range, and 3) the energy band gap of the solid solution is direct for compositions %. It is found that at ambient conditions, (GaP)x (ZnS) solid solutions with , 50% and 75% render promising hydrogen evolution photocatalysts for water splitting under visible light, owing to their favorable energy band gaps and band levels relative to vacuum.
MOF‐Based Nanotubes to Hollow Nanospheres through Protein‐Induced Soft‐Templating Pathways
Authors: Du Yingjie , Gao Jing , Zhou Liya , Ma Li , He Ying , Zheng Xuefang , Huang Zhihong , Jiang Yanjun
Published: January 2019

A controllable and facile strategy is established for constructing metal–organic frameworks‐based (MOF‐based) hollow composites via a protein‐induced soft‐templating pathway. Using metal‐sodium deoxycholate hydrogel as soft‐template, nanotubes are gained while the protein is absent. With the presence of protein, hollow nanospheres structure are prepared by changing the amount of protein. To verify the universality of the proposed pathway, two kinds of proteins (Burkholderia cepacia lipase and penicillin G acylase) and three kinds of MOF (ZIF‐8, ZIF‐67, and Fe‐MOF) are adopted as model proteins and materials, and the obtained protein‐containing composites (named protein@H‐MOF) possess high bioactivity and stability. This proposed strategy provides a facile method for preparing MOF‐based composites under mild conditions, facilitating the applications of MOF in the fields of biocatalyst construction, biomolecule encapsulation, and drug delivery.
Matrix Remodeling Enhances the Differentiation Capacity of Neural Progenitor Cells in 3D Hydrogels
Authors: Madl Christopher M. , LeSavage Bauer L. , Dewi Ruby E. , Lampe Kyle J. , Heilshorn Sarah C.
Published: January 2019

Neural progenitor cells (NPCs) are a promising cell source to repair damaged nervous tissue. However, expansion of therapeutically relevant numbers of NPCs and their efficient differentiation into desired mature cell types remains a challenge. Material‐based strategies, including culture within 3D hydrogels, have the potential to overcome these current limitations. An ideal material would enable both NPC expansion and subsequent differentiation within a single platform. It has recently been demonstrated that cell‐mediated remodeling of 3D hydrogels is necessary to maintain the stem cell phenotype of NPCs during expansion, but the role of matrix remodeling on NPC differentiation and maturation remains unknown. By culturing NPCs within engineered protein hydrogels susceptible to degradation by NPC‐secreted proteases, it is identified that a critical amount of remodeling is necessary to enable NPC differentiation, even in highly degradable gels. Chemical induction of differentiation after sufficient remodeling time results in differentiation into astrocytes and neurotransmitter‐responsive neurons. Matrix remodeling modulates expression of the transcriptional co‐activator Yes‐associated protein, which drives expression of NPC stemness factors and maintains NPC differentiation capacity, in a cadherin‐dependent manner. Thus, cell‐remodelable hydrogels are an attractive platform to enable expansion of NPCs followed by differentiation of the cells into mature phenotypes for therapeutic use.
NiCo2O4 Nanofibers as Carbon‐Free Sulfur Immobilizer to Fabricate Sulfur‐Based Composite with High Volumetric Capacity for Lithium–Sulfur Battery
Authors: Liu Ya‐Tao , Han Dian‐Dian , Wang Lu , Li Guo‐Ran , Liu Sheng , Gao Xue‐Ping
Published: January 2019

Both the energy density and cycle stability are still challenges for lithium–sulfur (Li–S) batteries in future practical applications. Usually, light‐weight and nonpolar carbon materials are used as the hosts of sulfur, however they struggle on the cycle stability and undermine the volumetric energy density of Li–S batteries. Here, heavy NiCo2O4 nanofibers as carbon‐free sulfur immobilizers are introduced to fabricate sulfur‐based composites. NiCo2O4 can accelerate the catalytic conversion kinetics of soluble intermediate polysulfides by strong chemical interaction, leading to a good cycle stability of sulfur cathodes. Specifically, the S/NiCo2O4 composite presents a high gravimetric capacity of 1125 mAh g−1 at 0.1 C rate with the composite as active material, and a low fading rate of 0.039% per cycle over 1500 cycles at 1 C rate. In particular, the S/NiCo2O4 composite with the high tap density of 1.66 g cm−3 delivers large volumetric capacity of 1867 mAh cm−3, almost twice that of the conventional S/carbon composites.
CAR‐T cells beyond CD19, UnCAR‐Ted territory
Authors: Leick Mark B. , Maus Marcela V.
Published: January 2019

CAR‐T cells have made dramatic inroads in targeting CD19‐positive B‐cell malignancies. This review focuses on application of CAR‐T cells in hematologic malignancies beyond targeting CD19, with specific attention to Hodgkin's lymphoma and acute myeloid leukemia.
Basic life support by citizens in Kawasaki City, Japan – a descriptive epidemiological study of out‐of‐hospital cardiac arrest patients
Authors: Shirakawa Kazuhiro , Takebayashi Toru , Kanao Kunio , Doi Kenji , Takemura Narihide , Shindo Ken , Saito Yutaka , Takuma Kiyotsugu
Published: January 2019

Aim

To better understand the current status and barriers to making basic life support a common practice among the citizens of Kawasaki City, Japan.

Method

We extracted data according to the Utstein‐style guidelines specifically regarding out‐of‐hospital cardiac arrests (OHCAs) of cardiac etiology. The items were as follows: (i) OHCA witnessed by a citizen, (ii) the victim received bystander cardiopulmonary resuscitation (CPR), (iii) an automatic external defibrillator was used by the witness. We compared the rate of each item and the 1‐month survival rates with the national average in Japan. We further divided Kawasaki City into three areas and compared each item. We also examined the rate of bystander CPR in each time period and location. Statistical analysis was carried out using the χ2‐test and Fisher's test.

Results

The 1‐month survival rates did not differ significantly from the national average for cases meeting conditions (i)–(iii): (i) 14.0% versus 13.3%, (ii) 19.1% versus 16.4%, (iii) 71.4% versus 53.3%, respectively. However, the rate of condition (i) was significantly lower (47.5% versus 55. 8%, P = 0.01). The rate of condition (ii) was higher in the northern area of Kawasaki City, as well as in a location other than the home in the daytime. The rate of condition (ii) was low in the home.

Conclusions

Although the 1‐month survival rates of OHCAs witnessed by citizens in Kawasaki City did not differ significantly from the national average, the low rate of bystander CPR was notable, especially in the southern and middle areas of the city and when the location was in the home, which implies that basic life support knowledge should be spread to these areas.
Assessing Carrier Recombination Processes in Type‐II SiGe/Si(001) Quantum Dots
Authors: Hackl Florian , Grydlik Martyna , Klenovský Petr , Schäffler Friedrich , Fromherz Thomas , Brehm Moritz
Published: January 2019

In this work, it is shown how different carrier recombination paths significantly broaden the photoluminescence (PL) emission bandwidth observed in type‐II self‐assembled SiGe/Si(001) quantum dots (QDs). QDs grown by molecular beam epitaxy with very homogeneous size distribution, onion‐shaped composition profile, and Si capping layer thicknesses varying from 0 to 1100 nm are utilized to assess the optical carrier‐recombination paths. By using high‐energy photons for PL excitation, electron‐hole pairs can be selectively generated either above or below the QD layer and, thus, clearly access two radiative carrier recombination channels. Fitting the charge carrier capture‐, loss‐ and recombination‐dynamics to PL time‐decay curves measured for different experimental configurations allows to obtain quantitative information of carrier capture‐, excitonic‐emission‐, and Auger‐recombination rates in this type‐II nano‐system.
Lower‐ and Higher‐Order Nonclassical Properties of Photon Added and Subtracted Displaced Fock States
Authors: Malpani Priya , Alam Nasir , Thapliyal Kishore , Pathak Anirban , Narayanan V. , Banerjee Subhashish
Published: January 2019

Nonclassical properties of photon added and subtracted displaced Fock states are studied using various witnesses of lower‐ and higher‐order nonclassicality. Compact analytic expressions are obtained for the nonclassicality witnesses. Using those expressions, it is established that these states and the states that can be obtained as their limiting cases (except coherent states) are highly nonclassical as they show the existence of lower‐ and higher‐order antibunching and sub‐Poissonian photon statistics, in addition to the nonclassical features revealed through the Mandel parameter, zeros of Q function, Klyshko's criterion, and Agarwal–Tara criterion. Further, some comparison between the nonclassicality of photon added and subtracted displaced Fock states have been performed using witnesses of nonclassicality. This has established that between the two types of non‐Gaussianity inducing operations (i.e., photon addition and subtraction) used here, photon addition influences the nonclassical properties more strongly. Further, optical designs for the generation of photon added and subtracted displaced Fock states from squeezed vacuum state have also been proposed.
Use of Isotope Effects To Understand the Present and Past of the Atmosphere and Climate and Track the Origin of Life
Authors: Thiemens Mark H. , Lin Mang
Published: January 2019

Stable isotope ratio measurements have been used as a measure of a wide variety of processes, including solar system evolution, geological formational temperatures, tracking of atmospheric gas and aerosol chemical transformation, and is the only means by which past global temperatures may be determined over long time scales. Conventionally, isotope effects derive from differences of isotopically substituted molecules in isotope vibrational energy, bond strength, velocity, gravity, and evaporation/condensation. The variations in isotope ratio, such as 18O/16O (δ18O) and 17O/16O (δ17O) are dependent upon mass differences with δ17O/δ18O=0.5, due to the relative mass differences (1 amu vs. 2 amu). Relations that do not follow this are termed mass independent and are the focus of this Minireview. In chemical reactions such as ozone formation, a δ17O/δ18O=1 is observed. Physical chemical models capture most parameters but differ in basic approach and are reviewed. The mass independent effect is observed in atmospheric species and used to track their chemistry at the modern and ancient Earth, Mars, and the early solar system (meteorites).
Ein Hybrid‐Anion für ionische Flüssigkeiten und Batterieelektrolytanwendungen: Halb Triflamid, halb Carbonat
Authors: Gunderson‐Briggs Kaitlyn E. , Rüther Thomas , Best Adam S. , Kar Mega , Forsyth Craig , Izgorodiana Ekaterina I. , MacFarlane Douglas R. , Hollenkamp Anthony F.
Published: January 2019

Die Synthese eines neuen Imid‐Anions, Methylcarbonat(trifluormethansulfonyl)imid (MCTFSI), und die physikochemischen Eigenschaften seiner Natrium‐ und N‐Butyl‐N‐methylpyrrolidinium‐Salze werden beschrieben. Strukturelle Informationen aus der Röntgenstrukturanalyse des Natriumsalzes werden bezüglich Ladungsverteilung, Koordinationseigenschaften und elektrochemischem Verhalten im Vergleich zu den analogen Imiden Bis(trifluormethansulfonyl)imid (TFSI) und Bis(fluorsulfonyl)imid (FSI) diskutiert. Die aus der Studie des neuen Anions gewonnenen Erkenntnisse unterstreichen und bestärken das Konzept schwach koordinierender Anionen für die gezielte Entwicklung von Elektrolytsalzen.
Atomically Tailored Gold Nanoclusters for Catalytic Application
Authors: Higaki Tatsuya , Li Yingwei , Zhao Shuo , Li Qi , Li Site , Du Xiang‐Sha , Yang Sha , Chai Jinsong , Jin Rongchao
Published: January 2019

Recent advances in the synthetic chemistry of atomically precise metal nanoclusters (NCs) have significantly broadened the accessible sizes and structures. Such particles are well defined and have intriguing properties, thus, they are attractive for catalysis. Especially, those NCs with identical size but different core (or surface) structure provide unique opportunities that allow the specific role of the core and the surface to be mapped out without complication by the size effect. Herein, we summarize recent work with isomeric Aun NCs protected by ligands and isostructural NCs but with different surface ligands. The highlighted work includes catalysis by spherical and rod‐shaped Au25 (with different ligands), quasi‐isomeric Au28(SR)20 with different R groups, structural isomers of Au38(SR)24 (with identical R) and Au38S2(SR)20 with body‐centred cubic (bcc) structure, and isostructural [Au38L20(PPh3)4]2+ (different L). These isomeric and/or isostructural NCs have provided valuable insights into the respective roles of the kernel, surface staples, and the type of ligands on catalysis. Future studies will lead to fundamental advances and development of tailor‐made catalysts.
The functionality of the hybrid systems driven by molecular dimension of the guest copper Schiff‐base complexes entrapped in Zeolite‐Y
Authors: Kumari Susheela , Choudhary Archana , Ray Saumi
Published: January 2019

On encapsulation inside the supercage of zeolite‐Y planar Cu (II)–Schiff base complexes show the modified structural, optical and functional properties. The electronic effect of the different substituent groups present in the catalyst plays the decisive role towards their reactivity in the homogeneous phase but after the encapsulation in zeolite Y, reactivity is mainly governed by the molecular dimensions of the guest complexes rather than the electronic factor of the substituent groups attached on them. These systems are well characterized with the help of different characterization tools like XRD analysis, SEM ‐ EDX, AAS, FTIR, XPS, DSC, TGA, BET and UV–Visible spectroscopy and the comparative optical and catalytic studies have provided a rational explanation of enhanced reactivity of zeolite encapsulated metal complexes for various oxidation reactions compared to their corresponding solution states.
Insights into the integrated effects of polymeric pretreatment and catalytic hydrotreatment of light gas oil
Authors: Olomola Abidemi , Misra Prachee , Chitanda Jackson M. , Dalai Ajay K. , Adjaye John
Published: January 2019

A study has been carried out in detail to measure the effects of the removal of nitrogen compounds on the hydrotreatment of light gas oil (LGO) using a synthesized polymer consisting of a polymer support, copolymer of glycidyl methacrylate and ethylene glycol dimethacrylate (PGMA‐co‐EDGMA), a π‐acceptor moiety (2,4,5,7‐tetranitrofluorenone, TENF), and a three‐carbon linker (diaminopropane, DAP (3)). The primary focus of this paper is first to study the effects of selectively removing nitrogen compounds on the hydrotreatment of LGOs. Removal of these catalyst inhibiting and poisoning compounds prior to hydrotreatment will help in improving the hydroprocessing efficiency as well as in reducing the chemical fouling, thus improving the catalyst life. Second, the effectiveness on the reusability of bulk polymer after regeneration was studied. To achieve this, nitrogen compounds from LGO were adsorbed on the synthesized polymer by mixing polymer and LGO. The polymer was regenerated by washing with toluene in a Soxhlet apparatus. Hydrotreating experiments were performed in a pilot scale trickle‐bed reactor. To create a baseline for monitoring the hydrotreatment activity, untreated LGO (without polymer adsorption) was hydrotreated with a commercial NiMo/γ‐Al2O3 catalyst and analyzed for nitrogen, sulfur, and aromatics content. The pretreated feed (with polymer adsorption) was also hydrotreated, and the results were compared. The results show that prior selective removal of nitrogen compounds improved overall hydrotreatment activity and resulted in additional decrease of 18.7%, 8.3%, and 9.4% in total nitrogen, sulfur, and aromatics content, respectively.
Materials containing benzocyclobutene units with low dielectric constant and good thermostability prepared from star‐shaped molecules
Authors: Wei Xuelian , Hu Huan , Li Xian , Yin Qiang , Fan Li , Huang Yawen , Yang Junxiao
Published: January 2019

With the development of ultralarge‐scale integrated circuits, polymers with low dielectric constant and high thermal stability have aroused great interest. We prepared two novel bridged siloxane‐based benzocyclobutene (BCB) star‐shaped monomers, tetrakis[dimethyl siloxy‐4‐(1′,1′‐dimethyl‐1′‐ethyl silicon)‐benzocyclobutene] (TDSDES‐BCB) and tetrakis(hexamethyl siloxane vinyl‐benzocyclobutene) (THSV‐BCB), and the corresponding resins were obtained by curing. The structures of TDSDES‐BCB and THSV‐BCB were confirmed by 1H‐NMR, 13C‐NMR, and 29Si‐NMR spectra and time‐of‐flight mass spectrometry analysis. The curing behavior of these monomers was investigated by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dielectric constant of cured TDSDES‐BCB is only 2.43 at 10 MHz (that of THSV‐BCB is 2.46). In addition, these resins display high thermal stability: the 5 wt % weight loss temperature of cured TDSDES‐BCB is about 467 °C (454 °C for THSV‐BCB resin). The excellent low dielectric property is attributable to the free volume created by the star‐shaped structure and crosslinked network structure of BCB after curing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47458.
Nonisothermal simulation on pressure during resin transfer molding
Authors: Yang Wenkai , Lu Shihong , Xiang Lintong , Liu Wenhao
Published: January 2019

High speed injection has been widely used in resin transfer molding (RTM), which improves manufacturing efficiency. This sometimes leads to excessive pressure within the mold, resulting in fiber destruction and mold deformation. Heating the mold and injection resin reduces the viscosity of resin, leading to influence on mold internal pressure. Selection of optimal mold and injection temperature for effective reduction of mold internal pressure has become a source of concern in the polymer industry. This article presents an outlook relationship between mold temperature, injection temperature, and mold internal pressure. It also showcases a temperature selection method angle to addressing this issue. The “FLUENT” software has been secondarily developed that gives an insight in using the three‐dimensional nonisothermal RTM simulation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47492.
Developing porous fibers by electrocentrifuge spinning system
Authors: Mobasheri Mina , Valipouri Afsaneh , Hosseini Ravandi Seyed Abdolkarim
Published: January 2019

In this study, polysulfone fibers with various surface morphologies were developed using electrocentrifuge spinning system. The effects of a number of parameters, including the solvent system, spinning system angular velocity, and relative humidity, on the fiber morphology were studied using field emission scanning electron microscopy, porosimetry [Brunauer–Emmett–Teller (BET)], and contact angle test. The results showed that the fibers prepared from the acetone/dimethylformamide (DMF) solvent system had higher micro/nano roughness than those fabricated from the tetrahydrofuran/DMF solvent system, that is to say, the higher the vapor pressure of the solvent, the higher the surface roughness. The acetone/DMF system created fibers that had internal porosity. Also, the relative humidity had a significant effect on providing micro/nano roughness, so that increasing the relative humidity led to an increase in the surface roughness. The increase in the angular velocity caused to stretch the micro/nano patterns and increase the fiber diameter. The results of the BET confirmed the microscopic observations. With the increase in the relative humidity and the use of the acetone/DMF system, porosity, and specific surface area of the fiber increased. X‐ray diffraction analysis was also performed and it was found that the presence of moisture did not affect the crystallinity of the fibers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47513.
Single step modification of micrometer‐sized polystyrene particles by electromagnetic polyaniline and sorption of chromium(VI) metal ions from water
Authors: Debnath Mithun K. , Rahman Mohammad A. , Minami Hideto , Rahman Mohammad M. , Alam Mohammad A. , Sharafat Mohammad K. , Hossain Mohammad K. , Ahmad Hasan
Published: January 2019

This article describes a single‐step reproducible approach for the surface modification of micrometer‐sized polystyrene (PS) core particles to prepare electromagnetic PS/polyaniline–Fe3O4 (PS/PANi–Fe3O4) composite particles. The electromagnetic PANi–Fe3O4 shell was formed by simultaneous seeded chemical oxidative polymerization of aniline and precipitation of Fe3O4 nanoparticles. The weight ratio of PS to aniline was optimized to produce core–shell structure. PS/PANi–Fe3O4 composite particles were used as adsorbent for the removal of Cr(VI) via anion‐exchange mechanism. The composite particles possessed enough magnetic property for magnetic separation. The adsorption was highly pH dependent. Adsorption efficiency reached 100% at pH 2 in 120 min when 0.05 g of composite particles was mixed with 30 mL 5 mg L−1 Cr(VI) solution. The adsorption isotherm fitted best with Freundlich model and maximum adsorption capacity approached 20.289 mg g−1 at 323 K. The prepared composite was found to be an useful adsorbent for the removal of soluble Cr(VI) ions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47524.
Acute N‐Acetylcysteine Administration Ameliorates Loss of Olfactory Neurons Following Experimental Injury In Vivo
Authors: Goncalves Stefania , Goldstein Bradley J.
Published: January 2019

The olfactory epithelium (OE) is the peripheral organ for the sense of smell, housing primary sensory neurons that project axons from the nose to the brain. Due to the presence of a basal stem cell niche, the adult mammalian OE is a dynamic tissue capable of replacing neurons following their loss. Nonetheless, certain conditions, such as blunt head trauma, can result in persistent olfactory loss, thought to be due to shearing of olfactory nerve filaments at the skull base, degeneration, and failures in proper regeneration/reinnervation. The identification of new treatment strategies aimed at preventing degeneration of olfactory neurons is, therefore, needed. In considering potential therapies, we have focused on N‐acetylcysteine (NAC), a glutathione substrate shown to be neuroprotective, with a record of safe clinical use. Here, we have tested the use of NAC in an animal model of olfactory degeneration. Administered acutely, we found that NAC (100 mg/kg, twice daily) resulted in a reduction of olfactory neuronal loss from the OE of the nose following surgical ablation of the olfactory bulb. At 1 week postlesion, we identified 54 ± 8.1 mature neurons per 0.5 mm epithelium in NAC‐treated animals vs. 28 ± 4.2 in vehicle‐treated controls (P = 0.02). Furthermore, in an olfactory cell culture model, we have identified significant alterations in the expression of several genes involved in oxidative stress pathways following NAC exposure. Our results provide evidence supporting the potential therapeutic utility for NAC acutely following head trauma‐induced olfactory loss. Anat Rec, 303:626–633, 2020. © 2019 American Association for Anatomy
Social complexity and the early social environment affect visual social attention to faces
Authors: Tsang Tawny , Johnson Scott , Jeste Shafali , Dapretto Mirella
Published: January 2019

Diminished attention to socially relevant information appears to be an early emerging risk factor associated with autism spectrum disorders (ASD). However, inconsistencies across studies suggest that atypicalities in visual social attention in infants at high‐risk for ASD during the first postnatal year may be subtle and more apparent under certain contexts. Here we explore factors that may moderate developmental trajectories in attention to faces, including the social complexity of the dynamic visual stimuli used to measure visual social attention and the early social environment of the infant as indexed by parental affectedness of ASD‐related traits. Across infants at both high (HR) and low risk for ASD, attention to faces increased during the first postnatal year, with overall greater attention being allocated to schematic faces in the simpler video stimulus. Moreover, greater parental affectedness of ASD‐related traits was associated with reduced developmental gains in attention to faces. For HR infants, greater attention to faces was positively associated with social communicative competence, including better joint attention skills and lower social impairments. Altogether, our findings highlight the importance of considering developmental level when selecting stimuli to longitudinally examine visual social attention, and the clinical relevance of including measures of infant's social environment in understanding early markers of ASD risk.Autism Res2019, 12: 445–457 © 2019 International Society for Autism Research, Wiley Periodicals, Inc.

Lay Summary

Attention to faces is an important means for infants to learn about the social world. The complexity of the social scene and an infant's early social environment both affect the amount of time infants at high‐ and low‐risk for ASD look at faces during the first postnatal year. For infants at high‐risk for ASD, greater attention to faces was associated with better social skills. Understanding an infant's social environment may have a positive impact on social communicative development.
Comparing the 1‐year impact of preschool autism intervention programs in two Canadian provinces
Authors: Smith Isabel M. , Flanagan Helen E. , Ungar Wendy J. , D'Entremont Barbara , Garon Nancy , den Otter Jeffrey , Waddell Charlotte , Bryson Susan E. , Tsiplova Kate , Léger Natalie , Vezina Francine , Murray Patricia
Published: January 2019

Autism spectrum disorder (ASD) is associated with early differences in children's social interactions, communication, and play/interests. In many countries, considerable resources are invested in early intensive behavioral intervention (EIBI) programs for children with ASD, which aim to build adaptive skills and prevent or treat problem behavior. However, these programs vary widely in structure and delivery. Research evidence supports the efficacy of EIBI, but large knowledge gaps remain about the effectiveness of publicly funded EIBI programs. With policy‐makers as formal research partners, we compared children's progress over 1 year in public preschool programs in adjacent Canadian provinces, New Brunswick (NB) and Nova Scotia (NS). In NB, children received up to 20 hr/week of comprehensive EIBI in a publicly funded, privately provided program. In NS, children received up to 15 hr/week of Pivotal Response Treatment and Positive Behavior Support delivered through the publicly funded healthcare system. In this observational parallel cohort study, we collected parent‐reported data on 298 NB preschoolers (76.5% boys) and 221 NS preschoolers (86.9% boys) at EIBI start and 1 year later. Multilevel analysis revealed significant differences at baseline: NS children were older, with lower adaptive functioning and more severe ASD symptoms than NB children. Despite these pre‐treatment differences that favor NB, children in both provinces showed similar adaptive functioning gains and reductions of maladaptive behavior. No changes were seen in mean ASD symptom severity in either province over time. Results highlight the value of evaluating interventions in their implementation contexts, and have important implications for devising optimal ASD policy. Autism Research 2019, 12: 667–681. © 2019 International Society for Autism Research,Wiley Periodicals, Inc.

Lay Summary

We need to know more about the impact of different forms of early intensive behavioral intervention (EIBI) for young children with autism spectrum disorder (ASD). We showed that preschoolers with ASD gained important skills while in public EIBI programs in two Canadian provinces. We also saw that differences in how EIBI programs are structured and characteristics of children who are served may affect outcomes. For these reasons, policy making requires evidence that fits the local context.
Improved power of familywise error rate procedures for discrete data under dependency
Authors: He Li , Heyse Joseph F.
Published: January 2019

In many applications where it is necessary to test multiple hypotheses simultaneously, the data encountered are discrete. In such cases, it is important for multiplicity adjustment to take into account the discreteness of the distributions of the p‐values, to assure that the procedure is not overly conservative. In this paper, we review some known multiple testing procedures for discrete data that control the familywise error rate, the probability of making any false rejection. Taking advantage of the fact that the exact permutation or exact pairwise permutation distributions of the p‐values can often be determined when the sample size is small, we investigate procedures that incorporate the dependence structure through the exact permutation distribution and propose two new procedures that incorporate the exact pairwise permutation distributions. A step‐up procedure is also proposed that accounts for the discreteness of the data. The performance of the proposed procedures is investigated through simulation studies and two applications. The results show that by incorporating both discreteness and dependency of p‐value distributions, gains in power can be achieved.
Highly Selective Fluorescent Probe Based on 2‐(2′‐Dansylamidophenyl)‐Thiazole for Sequential Sensing of Copper(II) and Iodide Ions
Authors: Kim Bo‐Yeon , Pandith Anup , Cho Chan Sik , Kim Hong‐Seok
Published: January 2019

A novel highly selective fluorescent probe based on 2‐(2′‐dansylamidophenyl)‐4‐phenylthiazole (1) is developed for sequential sensing of copper(II) and iodide ions in acetonitrile. The fluorescence mechanism is based on cation‐induced inhibition of excited‐state intramolecular hydrogen transfer, intramolecular charge transfer, and metal–ligand electron/charge transfer. Subsequent iodide‐induced extrusion of copper(II) results in partial revival of fluorescence. Probe 1 and its ensemble with copper (II) show high selectivity for copper(II) and iodide ions, respectively, in acetonitrile solution.