bluuebunny/crossref_metadata_2025 huggingface dataset:
ANALYSIS OF HIGH FREQUENCY BREAKING WAVES AND LOW FREQUENCY SURGES GENERATED IN HARBORS DUE TO PASSAGE OF DEEP-DRAFT TANKERS
Authors: Agarwal Arpit , Fenical Scott , McElhinney Kirsten , Carangelo Paul , Krams David
Published: February 2019

Clineâ€™s Point Marina, located in Port Aransas, TX, has been experiencing detrimental conditions near the marinaâ€™s entrance and within the marina itself during the passage of deep-draft ship traffic. The wave activity is primarily generated by pressure field effects from large, laden outbound vessels in Corpus Christi Ship Channel (CCSC). The basin was originally protected by an approximately 180 ft. long breakwater constructed in 1976 on the west side of the entrance which by 1980 has deteriorated and partially failed to 120 ft. long breakwater and continued deteriorating over time, reaching its approximate 60 ft. long current condition by 2003. The deterioration of this breakwater has reportedly resulted in enhanced penetration of deep-draft vessel wave activity into the marina (Figure 1). Mott MacDonald (MM) evaluated the mechanisms by which waves are generated in the navigation channel, transform, and enter the harbor, quantified the level of protection afforded by past and present entrance breakwater configuration(s), and developed conceptual alternatives for improving conditions inside the marina.
NUMERICAL MODELING OF NON-BREAKING, IMPULSIVE BREAKING, AND BROKEN WAVE INTERACTION WITH ELEVATED COASTAL STRUCTURES
Authors: Park Hyoungsu , Do Trung , Tomiczek Tori , Cox Daniel T. , Van de Lindt John W.
Published: February 2019

Hurricanes generate elevated surge levels and strong waves that can cause extensive damage to buildings and other coastal infrastructure, especially those located in low-lying coastal regions. The history of recorded damage on buildings near the shoreline from past storms indicates that the intensity of storms and resulting damage has increased over the past 30 years (Emanuel, 2005). For example, the United States has been impacted by recent events such as Hurricanes Katrina (2005), Ike (2008), Sandy (2012), and Harvey (2017). Computational Fluid Dynamics (CFD) models have been widely developed and applied to estimate the wave pressure and forces; advances in recent years have been supported by an increase in computation power, which allows more detailed calculations of the complex hydrodynamics associated with wave action. The performance of CFD models must be validated or verified through detailed comparisons with benchmark tests (e.g. analytic solutions or physical experiments).
A SOLUTION TO THE OVER-PRODUCTION OF TURBULENCE BENEATH SURFACE WAVES IN RANS MODELS
Authors: Fuhrman David R. , Larsen Bjarke Eltard
Published: February 2019

CFD simulations of breaking waves with RANS models over the past 20 years have shown a marked tendency to severely over-predict turbulence levels, both outside and within the surf zone. The reason is most likely due to the inherent instability of turbulence closure models, as originally diagnosed by Mayer & Madsen (2000). While they proposed an ad-hoc fix, a fundamentally sound solution to this wide-spread problem has, to date, eluded the coastal and ocean engineering modeling community.
A CONSISTENT DESCRIPTION OF THE SPATIAL DISTRIBUTION OF WIND GENERATED WAVES WITHIN HURRICANES
Authors: Young Ian
Published: February 2019

In tropical and sub-tropical regions, hurricanes (or tropical cyclones or typhoons) represent the most extreme meteorological systems. The complex vortex structure of the winds in such storms also represent a demanding test of the physics of numerical models. Despite the apparent complexity of these systems, the fact that the intense low pressure systems are well formed means that the wind field can be parameterized with surprising accuracy. This feature of the wind field, together with extensive insitu buoy and remote sensing measurements means that a detailed understanding of the spatial distribution of the waves and the form of the directional spectrum is emerging. This paper will summarize the various data sets available and present a consistent description of the hurricane wave field suitable for coastal and ocean engineering applications.
NUMERICAL MODELLING OF KINEMATICS AND DYNAMICS OF SPILLING AND PLUNGING BREAKERS IN SHALLOW WATERS
Authors: Chella Mayilvahanan Alagan , Bihs Hans
Published: February 2019

Wave breaking is a complex two-phase flow process that strongly influences the air-water interaction. A number of physical processes are involved in the exchange of mass, momentum and energy between air and water interaction during the wave breaking process. In shallow waters, waves undergo different transformation processes such as shoaling, refraction, diffraction and breaking due to their non-linear interaction with the seabed. Thus, the associated hydrodynamics are rather complicated to understand when compared to wave breaking in deep water (Lin, 2008). In the present numerical study, a two phase flow CFD model REEF3D (Bihs et al. 2016) is used to model and investigate the hydrodynamics of spilling and plunging breakers over a slope. An accurate modeling of the wave breaking process is still highly demanding due to the strong non-linear air-water interaction and turbulent production at the free surface. The numerical wave tank is based on the incompressible Reynolds Averaged Navier-Stokes (RANS) equations together with the level set method for free surface and the k-Ï‰ model for turbulence (Alagan Chella et al. 2015). The model uses the 5th-order Weighted Essentially Non- Oscillatory (WENO) scheme for the convective discretization and the 3rd-order TVD Runge Kutta Scheme for the time discretization. A staggered grid method is employed in the model in order to achieve a stronger coupling between the pressure and velocity. The model is fully parallelized with the domain decomposition method and MPI (Message passing interface).
WAVE INTERACTION WITH SINGLE AND TWIN VERTICAL AND SLOPED SLOTTED WALLS
Authors: Al Anjari Noor , Al Khalidi Mohamad , Neelamani Subramaniam
Published: February 2019

The performance of single and twin slotted walls of varying porosity and slope angles is experimentally investigated, in order to understand the wave-structure interaction and to asses the characteristics of wave transmission, wave reflection, and wave energy dissipation under random wave conditions.
NUMERICAL INVESTIGATION OF BREAKING IRREGULAR WAVES OVER A SUBMERGED BAR WITH CFD
Authors: Aggarwal Ankit , Chella Mayilvahanan Alagan , Kamath Arun , Bihs Hans
Published: February 2019

The study of breaking irregular waves is of great practical interest, because of the waves found in the nature. Regular waves are seldom found in the field. Irregular waves can be viewed as the superposition of a number of regular waves (wave components) with the different frequencies and the amplitudes. The breaking process for irregular waves is more complex as compared to breaking regular waves. The energy transfer between the individual wave components of different frequencies also takes place during the breaking process. Due to this, the spectral characteristics of the incident wave spectrum change during the breaking process. The main purpose of the study is to investigate the hydrodynamics during the interaction of breaking irregular waves with a submerged bar.
APPLICATION AND MODIFICATION OF GODA FORMULAE FOR NONIMPULSIVE WAVE FORCES ON ELEVATED COASTAL STRUCTURES
Authors: Tomiczek Tori , Wyman Amy , Park Hyoungsu , Cox Daniel T.
Published: February 2019

With an increase in both the population densities in coastal communities and the frequency of high-intensity tropical cyclones in recent years, effective strategies to mitigate wave and surge-induced structural damage are essential to ensure community resilience. To prevent damage in vulnerable areas, structures must be constructed or retrofitted to withstand the wave and surge induced forces associated with extreme events. Accurately predicting the pressure distributions and forces caused by hurricane waves is a critical first step in establishing reliable design standards and construction practices. While progress has been made in the estimation of wave-induced horizontal loads on vertical walls and breakwaters or vertical loads on elevated slabs based on previous theoretical, experimental, and numerical investigations, the results of these studies may not directly apply to the geometries of coastal houses, which comprise a major portion of the building stock in coastal communities. Many coastal residences are elevated above ground; thus, methods must be developed that can predict both the horizontal and the vertical forces acting on the structure. This work uses results from a large scale experimental dataset to develop a robust methodology for estimating the wave-induced horizontal and vertical pressure distributions on an elevated structure.
WAVE FORECASTING AT THE SITE -- A PRACTICAL SOLUTION FOR TERMINAL OPERATION AND PLANNING
Authors: Xing Xiuying , Millar Gillian , Branyon Jacqueline , Schroeder Joel
Published: February 2019

Due to the capital investment cost, procurement and construction schedule, and in some cases the permissions and environmental restrictions, the oil and LNG terminals tend to move more offshore nowadays. Survivability of the facility and operational downtime becomes an issue because of the considerably more challenging metocean conditions. In most cases, metocean conditions (typically related to swell) that dictate terminal operations are determined from ship mooring studies. A slight variation in wave height, period or direction could shift the condition from â€˜operationalâ€™ to â€˜downtimeâ€™. However, how do commissioned terminals make critical decisions on whether or when to shut down operations? A precise wave forecast at the terminal site becomes more critical than ever for terminal planning and operation.
PREDICTION OF SMALL BAY FLOODING THROUGH TIDAL INLET AND BY WAVE OVERTOPPING OF BARRIER BEACH
Authors: Zhu Tingting , Kobayashi Nobuhisa
Published: February 2019

Low-laying barrier beach is easily overtopped by waves during a severe storm, resulting in increased water level in the inland bays and extensive flooding along the long bay shoreline. Kobayashi and Zhu (2017) developed a simple analytical model to predict bay peak still-water elevation in Indian River Bay and Rehoboth Bay for given ocean peak still-water elevation and surge duration at Lewes . 27 storms identified during 2005-2015 were used to calibrate the dimensionless parameter K* related to the inlet and bay characteristics. The agreement is within 10% at tide gauges I and R and within 30% at tide gauge D.
LARGE-SCALE PHYSICAL MODELING OF COASTAL PROTECTION PROVIDED BY A MODEL RHIZOPHORA MANGROVE FOREST
Authors: Maza Maria , Lara Javier L. , Losada Inigo J.
Published: February 2019

Mangrove forests exist in intertidal areas of tropical zones and most are characterized by their complex root systems, which attenuates flow energy. Among the mangrove species, Rhizophora species is the most common one, representing approximately 90% of the world mangrove distribution (Ohira et al., 2013). In addition, this species is used in the majority of restoration projects. Rhizophora plants are characterized by their aerial roots, which form a network above the substrate. Although several studies have been performed in the last decade to characterize flow interaction with mangrove trees (e.g.: Zhang et al., 2015), there is still a lack of knowledge of the forces exerted on the trees and the attenuation produced under waves, currents and waves and currents flowing simultaneously action.
NUMERICAL INVESTIGATION OF PLUNGING BREAKERS OVER A POROUS ARTIFICIAL SURF REEF
Authors: Jensen Bjarne , Geertsen Karl-SÃ¸ren , RÃ¸nby Johan , Mortensen Simon B.
Published: February 2019

This paper presents the results of a numerical investigation of breaking waves over an artificial surf reef (ASR). In the surfing industry, it has become common to establish artificial surf reefs to enhance the surfability at popular surf locations, or to attract surfers to new locations. Besides enhancing the surfing quality, an ASR can also be seen as a submerged detached breakwater, which is a well known type of structure for coastal protection. The construction of an ASR can therefore have the additional purpose of acting as a measure for coastal protection. Hereby the ASR becomes a multi-purpose reef.

In this paper, we focus on two aspects of an ASR in relation to the effect of the porous reef: 1) a general analysis of the hydrodynamics of a plunging breaker over a reef, and 2) evaluation of specific parameters for describing the surfability and safety of the plunging breaker. The novelty of the work presented lays in the detailed inclusion of the porous reef structure in a numerical model that is applied for designing and evaluating an ASR.
RELATION BETWEEN SHAPE OF EXTREME WAVE HEIGHT DISTRIBUTIONS AND WEATHER SYSTEM
Authors: Chiwata Maki , Shimura Tomoya , Mori Nobuhito
Published: February 2019

The extreme value analysis of wave height has been used to estimate design value of coastal structure design. The procedure of extreme value analysis is standardized but distributions change highly depending on target locations. A long-term atmospheric reanalysis is useful for engineering applications to complement observation data. Although the reanalysis dataset was insufficient for coastal engineering applications due to shorter length of period and sparse spatial resolution of modeling, recent reanalysis (e.g. CFSR) give reasonable performance for engineering applications as wave climate both accuracy and length of periods (e.g. Menendez and Losada, 2017). This study analyzes characteristics of extreme wave heights and understands relation between extreme wave height distribution and its dependence on weather systems based on long-term analysis and observed data.
FULLY NONLINEAR MODELING OF NEARSHORE WAVE PROPAGATION INCLUDING THE EFFECTS OF WAVE BREAKING
Authors: Papoutsellis Christos E. , Yates Marissa L. , Simon Bruno , Benoit Michel
Published: February 2019

Nearshore wave modeling over spatial scales of several kilometers requires balancing the fine-scale modeling of physical processes with the modelâ€™s accuracy and efficiency. In this work, a fully nonlinear potential flow model is proposed as a compromise between simplified linear, weakly nonlinear or weakly dispersive models and direct CFD approaches. The core of present approach is the use of a series representation for the velocity potential. This series contains prescribed vertical functions and allows the determination of the velocity potential in terms of unknown horizontal functions. The resulting dimensionally reduced model retains the structure of the Hamiltonian water wave system Zakharov (1968), Craig & Sulem (1993), avoiding the solution of the Laplace problem for the potential. Instead, a numerically convenient linear system of horizontal equations needs to be solved at each step in the temporal evolution. No simplifications concerning the deformation of the physical boundaries are introduced, apart from the typical requirement of a smooth, non-overturning free surface and seabed. The main limitation of this formulation is its inability to account for wave breaking. The treatment of this process is the subject of the present work. Two different techniques are implemented in the present model. Simulation results are compared to laboratory measurements for two test cases: (1) shoaling and breaking of regular waves over a barred bathymetry Beji & Battjes (1993) and (2) shoaling and breaking of regular waves on a plane beach Ting & Kirby (1994).
VERIFICATION OF IMPULSIVE WAVE PRESSURE DUE TO SOLITARY WAVES BASED ON TWO-PHASE FLOW SIMULATOR
Authors: Fujiwara Kazuhiro , Igarashi Hiromu , Seki Katsumi , Arikawa Taro
Published: February 2019

One of the effective protection facility against a huge tsunami is a seawall. The wave force of tsunami acting on such a seawall has been studied by many researchers so far. According to Takahashi et al. (1983), it is important to consider the following two factor for prediction of impulsive wave pressure. One is the angle between the wave front and the wall, and the other is compressibility of air. On the other hand, establishment of prediction method using numerical simulation has been attempted. As mentioned above, it is important to calculate the angle between the wave front and the wall, and in order to predict impulsive wave pressure accurately, a computational model which can treat complex interface deformation is necessary. In this study, we analyze wave pressure of solitary waves using gas-liquid two-phase simulator and examine its applicability. And also, we examine computational efficiency and speed of its simulator.
EDGE WAVE INDUCED BY AN ATMOSPHERIC PRESSURE DISTURBANCE MOVING ALONG A SLOPING BEACH
Authors: Chen Yixiang , Niu Xiaojing
Published: February 2019

Edge wave can be generated by an atmospheric pressure disturbance moving along the shoreline on a sloping beach. A two-dimensional numerical model based on non-linear shallow water equations is established and a set of numerical experiments are conducted to study the edge wave packets evolution in coastal ocean. In light of the analytical solutions by Greenspan, some dominant factors are discussed, such as disturbance spatial size, translation speed, its location and the slope inclination, that influence the generation conditions and evolution process of edge waves. The results indicate on what circumstances significant edge waves will be excited and how long it takes for the wave growth.
A MULTIVARIATE STATISTICAL MODEL TO SIMULATE STORM EVOLUTION
Authors: Lira-Loarca Andrea , Cobos Manuel , Baquerizo AsunciÃ³n , Losada Miguel A.
Published: February 2019

The design and management of a coastal structure must take into account not only the different levels of damage along its useful life but also the construction, reparation and dismantling costs. Therefore, it should be addressed as an optimization problem that depends on random multivariate climate variables. In this context it is essential to develop tools that allow the simulation of storms taking into account all the main maritime variables and their evolution (Borgman, 1969). In general, most studies focusing on storm characterization and evolution use geometric shapes like the equivalent triangular storm (Bocotti, 2000; ROM-1.0; 2009) to characterize individual storms. Actual storms have, however, irregular and random histories. In this work, we present a simple and efficient methodology to simulate time-series of storm events including several maritime variables. This methodology includes the use of non-stationary parametric distributions (Solari, 2011) to characterize each variable, a vector autoregressive (VAR) model to describe the temporal dependence between variables, and a copula model to link the seasonal dependency of the storm duration and the interarrival time between consecutive storms.
A REVISIT ON THE LEADING WAVEFORM DUE TO A TRANSIENT DISTURBANCE
Authors: Chan I-Chi
Published: February 2019

A tsunami is a series of transient waves often triggered by a submarine earthquake over a sufficiently large area. The horizontal scale of the wave motion of tsunamis is considerably large, which can be a few hundreds of kilometers in the deep ocean. While a tsunami travels across an open ocean as a packet of very long waves, we have learned from the past tsunami events that the knowledge of the first few leading waves is of particular importance since it provides necessary information for tsunami scientists to predict the arrival time and runup height of the tsunami waves. Based on the theoretical arguments, experimental studies, or field observations, a number of simple wave models, namely sinusoidal waves, Gaussian profiles, solitary waves, N-waves among others, have been proposed in literature as the model waveforms for the leading tsunami waves. Undoubtedly, each model has achieved considerable success in representing leading waves when comparing to certain sets of field or laboratory data. However, a universal model for describing the waveform of leading tsunami waves is seemly still unavailable. In this paper, we will study theoretically the evolution of leading waves due to a sudden disturbance. We will first revisit the asymptotic solutions of linear dispersive equations for the leading wave train caused by a surface disturbance in a constant depth (Kajiura 1963). The applicability of these theoretical predictions will then be examined. Finally, we attempt to explore the connection between the profiles of the asymptotic solutions and the familiar sinusoidal waves and solitary waves.
PREDICTING THE BREAKING STRENGTH OF GRAVITY WATER WAVES FROM DEEP TO SHALLOW WATER
Authors: Kirby James T. , Derakhti Morteza , Banner Michael L. , Grilli Stephan
Published: February 2019

We revisit the classical but as yet unresolved problem of predicting the breaking strength of 2-D and 3-D gravity water waves.Our goal is to find a robust and local parameterization to predict the breaking strength of 2-D and 3-D gravity water waves. We use a LES/VOF model described by Derakhti & Kirby (2014) to simulate nonlinear wave evolution, breaking onset and post-breaking behavior for representative cases of focused wave packets or modulated wave trains. Using these numerical results, we investigate the relationship between the breaking strength parameter b and the breaking onset parameter B proposed by Barthelemy et al. (2018). While the results are potentially applicable more generally, in this paper we concentrate on breaking events due to focusing or modulational instability in wave packets over flat bottom topography and for conditions ranging from deep to intermediate depth, with depth to wavelength ratios ranging from 0.68 to 0.13.
RECENT ADVANCES IN 3D MODELLING OF WAVE-STRUCTURE INTERACTION WITH CFD MODELS
Authors: Lara Javier L. , Losada Inigo J. , Barajas Gabriel , Maza Maria , Di Paolo Benedetto
Published: February 2019

Numerical modelling of the interaction of water waves with coastal structures has continuously been among the most relevant challenges in coastal engineering research and practice. During the last years, 3D modelling based on RANS-type equations, has been the dominant methodology to address the mathematical modelling of wave and coastal structure interaction. However, the three-dimensionality of many flowstructure interactions processes demands overcoming existing modelling limitations. Under some circumstances relevant three-dimensional processes are still tackled using physical modelling. It has been shown that beyond numerical implementation of the well-known mathematical 3-D formulation of the Navier-Stokes equations, the application of 3-D codes to standard coastal engineering problems demands some additional steps to be taken. These steps could be classified into three main groups relevant to: a) the modelling of the physical processes; b) the use of the tool and c) the applicability of the codes. This work presents an analysis of the use of three-dimensional flow models to analyze wave interaction with coastal structures focusing on recent developments overcoming existing limitations. Last modelling advances, including the implementation of new physics and pre-and postprocessing tools will be shown with the aim of extending the use of three-dimensional modelling of wavestructure interaction in both coastal and offshore fields.
Phase‐Changeable Nanoemulsions for Oral Delivery of a Therapeutic Peptide: Toward Targeting the Pancreas for Antidiabetic Treatments Using Lymphatic Transport
Authors: Lin Po‐Yen , Chen Kuan‐Hung , Miao Yang‐Bao , Chen Hsin‐Lung , Lin Kun‐Ju , Chen Chiung‐Tong , Yeh Chun‐Nan , Chang Yen , Sung Hsing‐Wen
Published: February 2019

The oral absorption of a therapeutic peptide (such as exenatide; EXT) that can improve glycemic control in the treatment of type 2 diabetes is limited by multiple barriers of the intestinal epithelium. This work presents an oil‐structured nanoemulsion system that consists of a phase‐changeable fatty acid that allows EXT (EXT@PC/NEMs) to be delivered orally and absorbed efficiently in the small intestine. To construct an appropriate vehicle to encapsulate EXT, an oil‐in‐water single emulsion is generated at 37 °C, which is well above the melting point of the fatty acid but below the denaturation temperature of the peptide drug. The as‐prepared EXT@PC/NEMs are physically stable when stored at 4 °C, as they form a solid core, which prevents drug leakage. Upon their oral delivery at body temperature, the deformable liquid EXT@PC/NEMs may undergo effective cellular uptake, enhancing their permeability across the intestinal epithelium. The orally administered PC/NEMs significantly improve the bioavailability of EXT via intestinal lymphatic transport, ultimately accumulating in the pancreas, suggesting the possibility of orally delivering labile peptide drugs. The delivered EXT may act on pancreatic β‐ and α‐cells to stimulate insulin release and suppress glucagon secretion, respectively, reducing the blood glucose level, eventually having antidiabetic effects.
Sunlight‐Driven Wearable and Robust Antibacterial Coatings with Water‐Soluble Cellulose‐Based Photosensitizers
Authors: Jia Ruonan , Tian Weiguo , Bai Haotian , Zhang Jinming , Wang Shu , Zhang Jun
Published: February 2019

Herein, a simple, effective, and general strategy is demonstrated to obtain a water‐soluble and nontoxic cellulose‐based photosensitizer (CPS) with enhanced photodynamic antibacterial activity through introducing protoporphyrin IX (PpIX) and quaternary ammonium salt (QAS) groups onto the cellulose backbone. The synergistic effect of the anchoring and diluting effect of the cellulose backbone and the electrostatic repulsion between QAS groups effectively inhibit the π–π stacking of PpIX groups, thus the as‐prepared CPS exhibits markedly enhanced reactive oxygen species (ROS) yield. Meanwhile, the positively charged QAS groups endow the CPS with water‐solubility and a strong attractive force to bacteria. As a result, the CPS can rapidly and efficiently kill drug‐resistant bacteria strains, including E. coli and S. aureus, with a low light dose (2.4 J cm−2) and low concentration of PpIX groups (0.35 × 10−6m). Benefiting from the excellent processability and formability, the CPS is readily applied as a sunlight‐driven wearable and robust antibacterial coating by a spray coating and later crosslinking procedure.
Antibiotic‐Free Cationic Dendritic Hydrogels as Surgical‐Site‐Infection‐Inhibiting Coatings
Authors: Andrén Oliver C. J. , Ingverud Tobias , Hult Daniel , Håkansson Joakim , Bogestål Yalda , Caous Josefin S. , Blom Kristina , Zhang Yuning , Andersson Therese , Pedersen Emma , Björn Camilla , Löwenhielm Peter , Malkoch Michael
Published: February 2019

A non‐toxic hydrolytically fast‐degradable antibacterial hydrogel is herein presented to preemptively treat surgical site infections during the first crucial 24 h period without relying on conventional antibiotics. The approach capitalizes on a two‐component system that form antibacterial hydrogels within 1 min and consist of i) an amine functional linear‐dendritic hybrid based on linear poly(ethylene glycol) and dendritic 2,2‐bis(hydroxymethyl)propionic acid, and ii) a di‐N‐hydroxysuccinimide functional poly(ethylene glycol) cross‐linker. Broad spectrum antibacterial effect is achieved by multivalent representation of catatonically charged β‐alanine on the dendritic periphery of the linear dendritic component. The hydrogels can be applied readily in an in vivo setting using a two‐component syringe delivery system and the mechanical properties can accurately be tuned in the range equivalent to fat tissue and cartilage (G′ = 0.5–8 kPa). The antibacterial effect is demonstrated both in vitro toward a range of relevant bacterial strains and in an in vivo mouse model of surgical site infection.
Sulfur‐Catalyzed Oxidative Coupling of Dibenzyl Disulfides with Amines: Access to Thioamides and Aza Heterocycles
Authors: Nguyen Thanh Binh , Nguyen Le Phuong Anh , Nguyen Thi Thu Tram
Published: February 2019

In the presence of catalytic amounts of elemental sulfur, dibenzyl disulfide/DMSO was found to be an excellent thiobenzoylating agent of amines to provide a wide range of thioamides. The reaction becomes autocatalytic when anilines substituted by an o‐cyclizable group were used as nucleophile, leading to the corresponding 2‐aryl aza heterocycles.

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Fundamental Understanding of Photocurrent Hysteresis in Perovskite Solar Cells
Authors: Liu Pengyun , Wang Wei , Liu Shaomin , Yang Huagui , Shao Zongping
Published: February 2019

Organic–inorganic hybrid perovskite solar cells (PSCs) have become a promising candidate in the photovoltaic field due to their high power conversion efficiency and low material cost. However, the development of PSCs is limited by their poor stability under practical conditions in the presence of oxygen, moisture, sunlight, heat, and the current–voltage (I–V) hysteresis. In particular, the hysteretic I–V issue casts doubt on the validity of the photovoltaic performance results that are achieved, making it difficult to evaluate the authentic performance of PSCs. This review article focuses on understanding the I–V hysteresis behavior in PSCs and on exploring the possible reasons leading to this hysteresis phenomenon. The various strategies attempted to suppress the I–V hysteresis in PSCs are summarized, and a brief future recommendation is provided.
Impact of shift duration on alertness among air‐medical emergency care clinician shift workers
Authors: Patterson P. Daniel , Weaver Matthew D. , Markosyan Mark A. , Moore Charity G. , Guyette Frank X. , Doman Jack M. , Sequeira Denisse J. , Werman Howard A. , Swanson Doug , Hostler David , Lynch Joshua , Templin Megan A. , Rozario Nigel L. , Russo Lindsey , Hines Linda , Swecker Karen , Runyon Michael S. , Buysse Daniel J.
Published: February 2019

Background

Greater than half of Emergency Medical Services (EMS) shift workers report fatigue at work and most work long duration shifts. We sought to compare the alertness level of EMS shift workers by shift duration.

Methods

We used a multi‐site, 14‐day prospective observational cohort study design of EMS clinician shift workers at four air‐medical EMS organizations. The primary outcome was behavioral alertness as measured by psychomotor vigilance tests (PVT) at the start and end of shifts. We stratified shifts by duration (< 24 h and 24 h), night versus day, and examined the impact of intra‐shift napping on PVT performance.

Results

One hundred and twelve individuals participated. The distribution of shifts <24 h and 24 h with complete data were 54% and 46%, respectively. We detected no differences in PVT performance measures stratified by shift duration (P > 0.05). Performance for selected PVT measures (lapses and false starts) was worse on night shifts compared to day shifts (P < 0.05). Performance also worsened with decreasing time between waking from a nap and the end of shift PVT assessment.

Conclusions

Deficits in performance in the air‐medical setting may be greatest during night shifts and proximal to waking from an intra‐shift nap. Future research should examine alertness and performance throughout air‐medical shifts, as well as investigate the timing and duration of intra‐shift naps on outcomes.
De novo DDX3X missense variants in males appear viable and contribute to syndromic intellectual disability
Authors: Nicola Pantelis , Blackburn Patrick R. , Rasmussen Kristen J. , Bertsch Nicole L. , Klee Eric W. , Hasadsri Linda , Pichurin Pavel N. , Rankin Julia , Raymond F. Lucy ,   DDD Study, Clayton‐Smith Jill
Published: February 2019

DDX3X (Xp11.4) encodes a DEAD‐box RNA helicase that escapes X chromosome inactivation. Pathogenic variants in DDX3X have been shown to cause X‐linked intellectual disability (ID) (MRX102, MIM: 300958). The phenotypes associated with DDX3X variants are heterogeneous and include brain and behavioral abnormalities, microcephaly, hypotonia, and movement disorders and/or spasticity. The majority of DDX3X variants described are de novo mutations in females with ID. In contrast, most male DDX3X variants are inherited from an unaffected mother, with one documented exception being a recently identified de novo splice site variant. It has been suggested, therefore, that DDX3X exerts its effects through haploinsufficiency in females, and that affected males carry hypomorphic alleles that retain partial function. Given the lack of male de novo DDX3X variants, loss‐of‐function variants in this gene are suspected to be male lethal. Through whole‐exome sequencing, we identified three unrelated males with hemizygous missense DDX3X variants and ID. All three variants were confirmed by Sanger sequencing, with two established as de novo. In silico analyses were supportive of pathogenicity. We report the male phenotypes and compare them to phenotypes observed in previously reported male and female patients. In conclusion, we propose that de novo DDX3X variants are not necessarily male lethal and should be considered as a cause of syndromic ID in both males and females.
Excitonic Emission in van der Waals Nanotubes of Transition Metal Dichalcogenides
Authors: Shubina Tatiana V. , Remškar Maja , Davydov Valery Yu. , Belyaev Kirill G. , Toropov Alexey A. , Gil Bernard
Published: February 2019

Nanotubes (NTs) of transition metal dichalcogenides (TMDs), were first synthesized more than a quarter of a century ago; nevertheless, many of their optical properties have so far remained basically unknown. Herein, the state of the art in the knowledge of the optical properties of TMD NTs is presented. First, general properties of multilayered crystals are evaluated, and available data on related NTs are analyzed. Then, the technology for the formation and the structural characteristics of NTs are represented, focusing on the structures synthesized by chemical transport reaction. The core of this work is the presentation of the ability of synthesized TMD NTs to emit bright photoluminescence (PL), which has been discovered recently. By means of micro‐PL spectroscopy of individual tubes, we show that excitonic transitions relevant to both direct and indirect band gaps contribute to the emission spectra of the NTs despite having the dozens of monolayers in their walls. The performance of the tubes as efficient optical resonators is highlighted, where confined optical modes strongly affect the emission. Finally, a brief conclusion is presented, along with an outlook of the future studies of this novel radiative member of the NTs family, which have unique potential for different nanophotonics applications.
Light‐Driven Self‐Healing of Nanoparticle‐Based Metamolecules
Authors: Nan Fan , Yan Zijie
Published: February 2019

Metamolecules and crystals consisting of nanoscale building blocks offer rich models to study colloidal chemistry, materials science, and photonics. Herein we demonstrate the self‐assembly of colloidal Ag nanoparticles into quasi‐one‐dimensional metamolecules with an intriguing self‐healing ability in a linearly polarized optical field. By investigating the spatial stability of the metamolecules, we found that the origin of self‐healing is the inhomogeneous interparticle electrodynamic interactions enhanced by the formation of unusual nanoparticle dimers, which minimize the free energy of the whole structure. The equilibrium configuration and self‐healing behavior can be further tuned by modifying the electrical double layers surrounding the nanoparticles. Our results reveal a unique route to build self‐healing colloidal structures assembled from simple metal nanoparticles. This approach could potentially lead to reconfigurable plasmonic devices for photonic and sensing applications.
Interfacing Formate Dehydrogenase with Metal Oxides for the Reversible Electrocatalysis and Solar‐Driven Reduction of Carbon Dioxide
Authors: Miller Melanie , Robinson William E. , Oliveira Ana Rita , Heidary Nina , Kornienko Nikolay , Warnan Julien , Pereira Inês A. C. , Reisner Erwin
Published: February 2019

The integration of enzymes with synthetic materials allows efficient electrocatalysis and production of solar fuels. Here, we couple formate dehydrogenase (FDH) from Desulfovibrio vulgaris Hildenborough (DvH) to metal oxides for catalytic CO2 reduction and report an in‐depth study of the resulting enzyme–material interface. Protein film voltammetry (PFV) demonstrates the stable binding of FDH on metal‐oxide electrodes and reveals the reversible and selective reduction of CO2 to formate. Quartz crystal microbalance (QCM) and attenuated total reflection infrared (ATR‐IR) spectroscopy confirm a high binding affinity for FDH to the TiO2 surface. Adsorption of FDH on dye‐sensitized TiO2 allows for visible‐light‐driven CO2 reduction to formate in the absence of a soluble redox mediator with a turnover frequency (TOF) of 11±1 s−1. The strong coupling of the enzyme to the semiconductor gives rise to a new benchmark in the selective photoreduction of aqueous CO2 to formate.
Stacking‐Layer‐Number Dependence of Water Adsorption in 3D Ordered Close‐Packed g‐C3N4 Nanosphere Arrays for Photocatalytic Hydrogen Evolution
Authors: Lin Bo , Yang Guidong , Wang Lianzhou
Published: February 2019

Water adsorption capacity is a key factor to influence the photocatalytic H2 evolution activity of polymeric g‐C3N4 . Herein, we report the synthesis of 3D ordered close‐packed g‐C3N4 nanosphere arrays (CNAs) that significantly enhance the water adsorption capacity. Through precisely controlling the average stacking‐layer number (ASLN) of the nanospheres in CNAs, we reveal an interesting stacking‐layer‐number dependence of water adsorption in the newly designed CNAs for accelerating the H2 evolution reaction, which can be attributed to the differences in adsorption surface areas and adsorption sites endowed by the point‐defect cavities in sample CNAs.
From Octahedral to Icosahedral Metal–Organic Polyhedra Assembled from Two Types of Polyoxovanadate Clusters
Authors: Xu Na , Gan Hongmei , Qin Chao , Wang Xinlong , Su Zhongmin
Published: February 2019

Design and synthesis of metal–organic polyhedra (MOPs) with targeted geometries from predetermined secondary building units (SBUs) is a long‐standing challenge in chemistry and material science. Theoretical prediction shows that there are 6 possible polyhedra from the 3‐coordinated, 4‐coordinated octahedron ((3,4)‐c octahedron) to (3,5)‐c icosahedron with minimal transitivity (simplest possible). Except for one missing polyhedron (mtr) due to the unfavorable angles, we report five MOPs based on these structures, including an octahedral (3,4)‐c VMOP‐21 (rdo), an icosahedral (3,5)‐c VMOP‐25 (trc), and three intermediate derived trinodal (3,4,5)‐c VMOP‐22–24 (ghm, hmg, xum). Remarkably, all these MOPs obey the minimal transitivity principle and are consistent with geometrical predictions.
Nickel‐Catalyzed Thiolation of Aryl Halides and Heteroaryl Halides through Electrochemistry
Authors: Liu Dong , Ma Hong‐Xing , Fang Ping , Mei Tian‐Sheng
Published: February 2019

Transition‐metal‐catalyzed coupling reactions are useful tools for synthesizing aryl sulfur compounds. However, conventional transition‐metal‐catalyzed thiolation of aryl bromides and chlorides typically requires the use of strong base under elevated reaction temperature. Herein, we report the first examples of nickel‐catalyzed electrochemical thiolation of aryl bromides and chlorides in the absence of an external base at room temperature using undivided electrochemical cells.
Some new Ag(I), VO(II) and Pd(II) chelates incorporating tridentate imine ligand: Design, synthesis, structure elucidation, density functional theory calculations for DNA interaction, antimicrobial and anticancer activities and molecular docking studies
Authors: Abdel‐Rahman Laila H. , Abu‐Dief Ahmed M. , Shehata Mohamed R. , Atlam Faten M. , Abdel‐Mawgoud Azza A. Hassan
Published: February 2019

Some new complexes derived from VO(II), Ag(I) and Pd(II) metal ions and HNA imine ligand (L), i.e. (2‐((6‐allylidene‐2‐hydroxycyclohexa‐1,3‐dienylmethylene)amino)benzoic acid), have been prepared and their structures elucidated via molar conductance measurements, elemental analyses, infrared, NMR and electronic spectra and magnetic susceptibility estimations. Moreover, stability constants of the synthesized complexes were evaluated utilizing a spectrophotometric technique. On the basis of molar conductance and elemental analyses, the metal imine chelates have structure [M(L)], where M = Pd(II), VO(II) and Ag(I). The results indicate that the prepared HNA imine ligand acts as a tridentate moiety via nitrogen atom of azomethine group and two oxygen atoms of phenolic and carboxylic groups. All the complexes are found to be monomeric with 1:1 stoichiometry with square planar geometry for Pd(II), tetrahedral geometry for Ag(I) and distorted square pyramidal for VO(II). Theoretical density functional theory calculations were applied to verify the molecular geometry of the chelators and their metal chelates. The geometry optimization results are in agreement with experimental observations. The antimicrobial properties of the prepared HNA imine ligand and its metal chelates were evaluated against numerous plant pathogenic fungi and bacteria. The results of these studies indicate that the metal complexes exhibit a stronger antibacterial and antifungal effect compared to the imine ligand. In addition, the interaction of the metal imine chelates with calf thymus DNA was observed by way of viscosity, gel electrophoreses and spectral studies. Absorption titration studies reveal that each of the complexes is an avid binder to calf thymus DNA. Also, there are appreciable changes in the relative viscosity of DNA, which are consistent with enhanced hydrophobic interaction of the aromatic rings and intercalation mode of binding. Additionally, the cytotoxic activity of the investigated compounds against various cancer cell lines shows promising results which makes them prospective compounds for antibiotic and anticancer medicament studies. Furthermore, docking studies of the prepared compounds were conducted for confirming the biological results.
Surface texture and barrier performance of poly(lactic acid)–cellulose nanocrystal extruded‐cast films
Authors: Liu Yuzhu , Matuana Laurent M.
Published: February 2019

In this study, we assessed the influence of cellulose nanocrystal (CNC) addition level (0.5–2 wt %) on the surface texture, thickness, and barrier properties of poly(lactic acid) (PLA) extruded‐cast films. Regardless of the CNC content, the addition of CNC increased the surface average roughness and maximum roughness of the PLA films in both the machine and cross‐machine directions because of the presence of CNC agglomerates. The increased roughness resulted in films with uneven thicknesses; this affected their accurate measurements with a conventional micrometer. Rather, accurate thickness measurements were obtained through the density method, a more appropriate thickness measurement method for films with rough surfaces. The permeability values were negatively correlated with the increased crystallinity. Both the water vapor permeability and oxygen permeability (OP) values decreased significantly by approximately 26–45 and 25–50%, respectively, as the CNC content increased from 0.5 to 2 wt % because of the tortuosity effect. The OP values of the neat PLA and composite films remained insensitive to changes in the relative humidity (from 0 to 75%) when they were tested at 23 °C. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47594.
Why do so few low‐ and middle‐income children attend a grammar school? New evidence from the Millennium Cohort Study
Authors: Jerrim John , Sims Sam
Published: February 2019

Proponents argue that grammar schools enhance social mobility by allowing high‐attaining pupils to attend elite schools, no matter what their social background. However, disadvantaged pupils cannot benefit from grammar schools unless they gain access to them. In this article, we use rich cohort data to investigate the strength of, and reasons for, the socio‐economic gradient in grammar school entrance rates. Presenting new evidence for England and Northern Ireland, we find stark differences in grammar school attendance by family income. Although differences in prior academic attainment can partly explain these gaps, parental school preferences and private tuition also play an important role. Entrance to grammar school therefore depends on birth and wealth, as well as academic attainment.
Targeted Proteomics Comes to the Benchside and the Bedside: Is it Ready for Us?
Authors: Arora Anjali , Somasundaram Kumaravel
Published: February 2019

While mass spectrometry (MS)‐based quantification of small molecules has been successfully used for decades, targeted MS has only recently been used by the proteomics community to investigate clinical questions such as biomarker verification and validation. Targeted MS holds the promise of a paradigm shift in the quantitative determination of proteins. Nevertheless, targeted quantitative proteomics requires improvisation in making sample processing, instruments, and data analysis more accessible. In the backdrop of the genomic era reaching its zenith, certain questions arise: is the proteomic era about to come? If we are at the beginning of a new future for protein quantification, are we prepared to incorporate targeted proteomics at the benchside for basic research and at the bedside for the good of patients? Here, an overview of the knowledge required to perform targeted proteomics as well as its applications is provided. A special emphasis is placed on upcoming areas such as peptidomics, proteoform research, and mass spectrometry imaging, where the utilization of targeted proteomics is expected to bring forth new avenues. The limitations associated with the acceptance of this technique for mainstream usage are also highlighted. Also see the video abstract here https://youtu.be/mieB47B8gZw.
The discovery and characterization of K‐563, a novel inhibitor of the Keap1/Nrf2 pathway produced by Streptomyces sp
Authors: Hori Ran , Yamaguchi Kozo , Sato Hidetaka , Watanabe Miwa , Tsutsumi Kyoko , Iwamoto Susumu , Abe Masayuki , Onodera Hideyuki , Nakamura Satoshi , Nakai Ryuichiro
Published: February 2019

Keap1/Nrf2 pathway regulates the antioxidant stress response, detoxification response, and energy metabolism. Previous reports found that aberrant Keap1/Nrf2 pathway activation due to Kelch‐like ECH‐associated protein 1 (Keap1) mutations or Nuclear factor E2‐related factor 2 (Nrf2) mutations induced resistance of cancer cells to chemotherapy and accelerated cell growth via the supply of nutrients. Therefore, Keap1/Nrf2 pathway activation is associated with a poor prognosis in many cancers. These previous findings suggested that inhibition of Keap1/Nrf2 pathway could be a target for anti‐cancer therapies. To discover a small‐molecule Keap1/Nrf2 pathway inhibitor, we conducted high‐throughput screening in Keap1 mutant human lung cancer A549 cells using a transcriptional reporter assay. Through this screening, we identified the novel Keap1/Nrf2 pathway inhibitor K‐563, which was isolated from actinomycete Streptomyces sp. K‐563 suppressed the expression of Keap1/Nrf2 pathway downstream target genes or the downstream target protein, which induced suppression of GSH production, and activated reactive oxygen species production in A549 cells. K‐563 also inhibited the expression of downstream target genes in other Keap1‐ or Nrf2‐mutated cancer cells. Furthermore, K‐563 exerted anti‐proliferative activities in these mutated cancer cells. These in vitro analyses showed that K‐563 was able to inhibit cell growth in Keap1‐ or Nrf2‐mutated cancer cells by Keap1/Nrf2 pathway inhibition. K‐563 also exerted synergistic combinational effects with lung cancer chemotherapeutic agents. An in vivo study in mice xenotransplanted with A549 cells to further explore the therapeutic potential of K‐563 revealed that it also inhibited Keap1/Nrf2 pathway in lung cancer tumors. K‐563, a novel Keap1/Nrf2 pathway inhibitor, may be a lead compound for development as an anti‐cancer agent.