bluuebunny/crossref_metadata_2025 huggingface dataset:
Unconditional nonlinear stability for double‐diffusive convection in a porous medium with temperature‐dependent viscosity and density
Authors: Hameed Ayat A. , Harfash Akil J.
Published: August 2019

In this study, fluid flow in a porous medium is analyzed using a Forchheimer model. The problem of double‐diffusive convection is addressed in such a porous medium. We utilize a higher‐order approximation for viscosity‐temperature and density‐temperature, such that the perturbation equations contain more nonlinear terms. For unconditional stability, nonlinear stability has been achieved for all initial data by utilizing the or norms. It also shows that the theory of is not sufficient for such unconditional stability. Both linear instability and nonlinear energy stability thresholds are tested using three‐dimensional (3D) simlations. If the layer is salted above and salted below then stationary convection is dominant. Thus the critical value of the linear instability thresholds occurs at a real eigenvalue , and our results show that the linear theory produces the actual threshold. Moreover, it is known that with the increase of the salt Rayleigh number, Rc, the onset of convection is more likely to be via oscillatory convection as opposed to steady convection. The 3D simulation results show that as the value of Rc increases, the actual threshold moves towards the nonlinear stability threshold, and the behavior of the perturbation of the solutions becomes more oscillatory.
Effects of double stratification on MHD chemically reacting second‐grade fluid through porous medium between two parallel plates
Authors: Kumar N. Naresh , Ojjela Odelu , Sastry D. R. V. S. R. K.
Published: August 2019

The present study focuses on the study of heat transfer in a magnetohydrodynamic double stratification fluid flow through porous channel. In getting the solution of Navier‐Stokes equations, we have adapted the similarity transformation technique to convert the partial differential equations into a coupled system of nonlinear ordinary differential equations. We further applied the fourth‐order Runge‐Kutta method with shooting technique to solve the problem numerically. The results are exhibited via graphs, and the analysis has been addressed for various flow characteristics with respect to the parameters concerned. It is found that thermal stratification enhances both temperature and heat transfer rates, and solutal stratification enhances concentration and mass transfer rates. Concentration decreases with increasing chemical reaction and it increases with stratification. A significant variation is observed between concentration profiles in the presence of stratification.
Developing Disciplinary Literacy in Mathematics: Learning From Professionals Who Use Mathematics in Their Jobs
Authors: Croce Keri‐Anne , K. McCormick Montana
Published: August 2019

Pedagogy within the field of disciplinary literacy can be shaped by those who use mathematics in their jobs. The authors draw on the results of a study that investigated language used by professionals who use mathematics in their jobs. The findings of the study suggest that professionals use language to determine the change requested by a client, create a solution, and present the solution within a narrative crafted for a specific audience. In addition, professionals are members of different language communities. The construct of a language community involves defining how roles and power structures specifically shape audiences for disciplinary language. The authors offer recommendations as to how student apprentices may examine language as they enter into language communities with professionals who become specialists/mentors. Students can also practice using language for specific purposes through a process called linguistic inquiry and discourse analysis.
In vivo hydroxyapatite scaffold performance in infected bone defects
Authors: Pearson Joseph J. , Gerken Nicholas , Bae Chunsik , Lee Kyu‐Bok , Satsangi Arpan , McBride Sean , Appleford Mark R. , Dean David D. , Hollinger Jeffrey O. , Ong Joo L. , Guda Teja
Published: August 2019

Critically sized bone defects are often compounded by infectious complications. The standard of care consists of bone autografts with systemic antibiotics. These injuries and treatments lead to donor site morbidity, antibiotic resistant strains of bacteria, and often end stage amputation. This study proposes an alternative to the autograft using a porous, hydroxyapatite (HA) scaffold evaluated with and without infection and antibiotics. Twenty‐four New Zealand white rabbits received either our HA scaffold or a pulverized autograft (PBA) within a surgically created critical‐sized defect in the femur. The two grafts were evaluated in either septic or aseptic defects and with or without antibiotic treatment. The HA scaffolds were characterized with micro computed tomography. Post‐euthanasia, micro computed tomography, histology, and white blood cells component analysis were completed. The HA had significantly greater (p < .001) mineralization to total volume than the PBA groups with 27.56% and 14.88%, respectively, and the septic HA groups were significantly greater than the aseptic groups both with and without antibiotics (p = .016). The bone quality denoted by bone mineral density was also significantly greater (p < .001) in the HA groups (67.01 ± 0.38 mgHA/cm3) than the PBA groups (64.66 ± 0.85 mgHA/cm3). The HA scaffold is a viable alternative to the bone autograft in defects with and without infection as shown by the quality and quantity of bone.
Fracture and Bone Mineral Density Response by Baseline Risk in Patients Treated With Abaloparatide Followed by Alendronate: Results From the Phase 3 ACTIVExtend Trial
Authors: Leder Benjamin Z , Zapalowski Carol , Hu Ming-Yi , Hattersley Gary , Lane Nancy E , Singer Andrea J , Dore Robin K
Published: August 2019

In the randomized, placebo-controlled, double-blind phase 3 ACTIVE study (NCT01343004), 18 months of abaloparatide 80 μg daily (subcutaneous injection) in postmenopausal women at risk of osteoporotic fracture significantly reduced the risk of vertebral, nonvertebral, clinical, and major osteoporotic fractures and significantly increased bone mineral density (BMD) versus placebo regardless of baseline risk factors. Women from the abaloparatide and placebo groups who completed ACTIVE were eligible for ACTIVExtend (NCT01657162), in which all enrollees received sequential, open-label monotherapy with alendronate 70 mg once weekly for up to 24 months. This prespecified analysis evaluated whether fracture risk reductions and bone mineral density (BMD) gains associated with abaloparatide during ACTIVE persisted through the full 43-month ACTIVE–ACTIVExtend study period in nine prespecified baseline risk subgroups. Baseline risk subgroups included BMD T-score at the lumbar spine, total hip, and femoral neck (≤ − 2.5 versus > − 2.5 and ≤ −3.0 versus > − 3.0), history of nonvertebral fracture (yes/no), prevalent vertebral fracture (yes/no), and age (<65 versus 65 to <75 versus ≥75 years). Forest plots display treatment effect. Treatment-by-subgroup interactions were tested using the Breslow-Day test, Cox proportional hazards model, and ANCOVA model. After the combined ACTIVE–ACTIVExtend study period, reductions in relative risk for new vertebral, nonvertebral, clinical, and major osteoporotic fractures were greater among patients in the abaloparatide/alendronate group than among those in the placebo/alendronate group across all nine baseline risk subgroups. BMD gains at the lumbar spine, total hip, and femoral neck were greater in the abaloparatide/alendronate group versus the placebo/alendronate group. No clinically meaningful interaction between treatment assignment and any baseline risk variable was observed. The sequence of abaloparatide for 18 months followed by alendronate for up to 24 months appears to be an effective treatment option for a wide range of postmenopausal women at risk for osteoporotic fractures. © 2019 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc.
Thermal Effect on Positive Patterned Self‐Assembled Monolayer Grown from a Droplet of Alkanethiol
Authors: Sannyal Arindam , Jang Joonkyung , Shajahan Md. , Saha Joyanta K.
Published: August 2019

Atomic force microscope technique is widely used for the spatial narrow deposition of molecules inside the bare space of preexisting self‐assembled monolayer (SAM) matrix. Using molecular dynamics simulation, we studied the formation of positively patterned SAM from a globule of 1‐octadecanethiol (ODT) on predesigned SAM matrix of 1‐dodecanethiol (DDT) and effect of temperature on it. The alkyl chains of ODT SAM were densely packed and ordered by means of chemisorption through sulfur atoms. The circular SAM of ODT contained defects due to the molecules those were standing upside down or trapped inside ODT SAM. We found that with the increase of temperature, these defects moved out by flipping of inverted ODT molecules or building spaces to be adsorbed on Au surface. The ODT molecules on the top of the pile of stable circular SAM or those are upside down and trapped disperse in a unique fashion namely serial pushing through which molecules firstly make a free space to enter inside the adsorbed thiol molecules and then push neighboring molecules to get enough space to be adsorbed on the gold surface. The stability of ODT SAM was confirmed by analyzing different structural properties such as tilt angle, tilt orientation. and backbone orientation. We also calculated the diffusion coefficient of the ODT molecules which were on the top of SAM island. © 2019 Wiley Periodicals, Inc.
Preliminary study: Descriptive analysis of longitudinal data on the international session of the Japan Primary Care Association annual conference, 2012–2018
Authors: Hirooka Nobutaka , Ban Nobutaro ,   the Japan Primary Care Association International Affairs Committee
Published: August 2019

Introduction

Japan Primary Care Association has launched an international session at annual conference since 2012. Longitudinal characteristics of the presentations were investigated.

Methods

Abstracts of the session were analyzed regarding type of presentation (oral/poster), category (research/clinical case/activity/review), and presenters' geographical location.

Results

The numbers of oral and poster presentations significantly increased. The most frequent presentation was research with cross‐sectional survey. Majority of presentations were clinical and less educational research, most of which were by Japanese.

Conclusion

The numbers of presentations in the international session increased, but the session should be used more rigorously to enhance primary care.
External validation and update of a prognostic model to predict mortality in hospitalized adults with RSV: A retrospective Dutch cohort study
Authors: Vos Laura M. , Oosterheert Jan Jelrik , Hoepelman Andy I. M. , Bont Louis J. , Coenjaerts Frank E. J. , Naaktgeboren Christiana A.
Published: August 2019

Respiratory syncytial virus (RSV) causes significant mortality in hospitalized adults. Prediction of poor outcomes improves targeted management and clinical outcomes. We externally validated and updated existing models to predict poor outcome in hospitalized RSV‐infected adults. In this single center, retrospective, observational cohort study, we included hospitalized adults with respiratory tract infections (RTIs) and a positive polymerase chain reaction for RSV (A/B) on respiratory tract samples (2005‐2018). We validated existing prediction models and updated the best discriminating model by revision, recalibration, and incremental value testing. We included 192 RSV‐infected patients (median age 60.7 years, 57% male, 65% immunocompromised, and 43% with lower RTI). Sixteen patients (8%) died within 30 days. During hospitalization, 16 (8%) died, 30 (16%) were admitted to intensive care unit, 21 (11%) needed invasive mechanical ventilation, and 5 (3%) noninvasive positive pressure ventilation. Existing models performed moderately at external validation, with C‐statistics 0.6 to 0.7 and moderate calibration. Updating to a model including lower RTI, chronic pulmonary disease, temperature, confusion and urea, increased the C‐statistic to 0.76 (95% confidence interval, 0.61‐0.91) to predict in‐hospital mortality. In conclusion, existing models to predict poor prognosis among hospitalized RSV‐infected adults perform moderately at external validation. A prognostic model may help to identify and treat RSV‐infected adults at high‐risk of death.
Characterizing satellite‐derived soil moisture and its relationship with rainfall over India
Authors: Vezhapparambu Sajith , Madhusoodanan M. S. , Sharma T. B. Vrinda , Ramesh Maneesha Vinodini
Published: August 2019

Understanding the spatial and temporal variations of soil moisture is important since the feedback between soil moisture and precipitation is a key control of the climate. This is also important as soil moisture data is a key input in regional climate models. The inter‐annual and inter‐decadal variability of soil moisture has been investigated here using the European Space Agency's Climate Change Initiative active and passive combined soil moisture product over different climate regimes of India. The observed soil moisture and rainfall are positively correlated and their relationship in this study suggests that both positive and negative feedback occur. The analysis showed an increasing soil moisture trend with a significant increase in the monsoon and autumn seasons for the past two decades over central India, where the frequency of extreme precipitation increased in the same period. An overall increase in soil moisture over the western arid region is also significant. A decreasing trend in soil moisture prevailed throughout the monsoon season over eastern India, where monsoon depressions make landfall, signalling the recent climate trends over the Indian subcontinent.
Robotically Simulated Pivot Shift That Represents the Clinical Exam
Authors: Colbrunn Robb W. , Dumpe Jarrod E. , Nagle Tara F. , Kolmodin Joel D. , Barsoum Wael K. , Saluan Paul M.
Published: August 2019

A thorough understanding of anterior cruciate ligament (ACL) function and the effects of surgical interventions on knee biomechanics requires robust technologies and simulation paradigms that align with clinical insight. In vitro orthopedic biomechanical testing for the elucidation of ACL integrity doesn't have an established testing paradigm to simulate the clinical pivot shift exam on cadaveric specimens. The study aim was to develop a robotically simulated pivot shift that represents the clinical exam. An orthopedic surgeon performed a pivot shift on an instrumented ACL‐deficient cadaver leg to capture 6 degree‐of‐freedom motion/loads. The same knee was mounted to the robot and the sensitivity of the motion/loading profiles quantified. Three loading profile candidates that generated positive pivot shifts on the instrumented knee were selected and applied to 7 ACL‐intact/deficient specimens and resulted in the identification of a profile that was able to induce a positive pivot shift in all ACL‐deficient specimens (
p < 0.001). The simulated shifts began at 22 ± 8° and ended at 33 ± 6° of flexion with the average magnitude of the shifts being 12.8 ± 3.2 mm in anterior tibial translation and 17.6 ± 4.3° in external tibial rotation. The establishment and replication of a robotically simulated clinical pivot shift across multiple specimens show the robustness of the loading profile to accommodate anatomical and experimental variability. Further evaluation and refinement should be undertaken to create a useful tool in evaluating ACL function and reconstruction techniques. Statement of clinical significance: Creation and successful demonstration of the simulated clinical pivot shift validates a profile for robotic musculoskeletal simulators to analyze ACL related clinical questions. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2601–2608, 2019
Size‐controlled graphene‐based materials prepared by annealing of pitch‐based cokes: G band phonon line broadening effects due to high pressure, crystallite size, and merging with D′ band
Authors: Pillet G. , Sapelkin A. , Bacsa W. , Monthioux M. , Puech P.
Published: August 2019

The influence of high pressure in the range of 0–15 GPa on the linewidth and the position of the Raman G band is investigated for graphene‐based materials with controlled crystallite sizes, La, obtained from pitch‐based cokes by increasing annealing temperature. It is observed that the linewidth of the G band increases significantly above the critical pressure, Pc ≈ 10 GPa, for all samples, whereas at atmospheric pressure, the linewidth neither depends on variation in the measurement temperature (<400 K) nor on excitation wavelengths. The crystallite size (varied using different annealing temperatures) is found not to influence the critical pressure associated with the modification of carbon hybridization. At the same time, the G band linewidth increases significantly for smaller crystallite sizes depending on the annealing temperature at atmospheric pressure due to the merging of the D′ and G phonon bands. This merging of the bands can be explained by a single phonon involved in two physical Raman processes, which cannot be discriminated.
Synthesis of ionic liquids with multifunctional tribological properties as excellent single‐component package additives for turbine oils
Authors: Keshavarz Shahriyar , Naimi‐Jamal Mohammad R. , Izadmanesh Yahya , Dekamin Mohammad G.
Published: August 2019

Three benzotriazole‐bearing imidoazolium‐based ionic liquids (ILs) have been synthesized. The ILs were identified by 1HNMR and Fourier‐transform infrared (FTIR) techniques. The thermogravimetric analysis showed that they are highly nonvolatile and have extremely high flash points. The synthesized ILs were used in turbine oil formulation, and their lubrication properties were critically examined and compared to commercially available package additives. The tribological tests proved that the ILs act as an effective antifriction, antiwear (AW), and extreme pressure (EP) additives. Performance studies indicated that the synthesized ILs impart excellent antioxidation and corrosion protection to the lubricant with minimum acidity change. The elemental analysis proved absence of toxic and dangerous elements in the lubricant, a confirmation that the ILs are potential environmentally friendly lubricants. The results also confirmed that the synthesized ILs are ideal single‐component package additives in the lubricant industry, i.e., one molecule imparts several favorable functionalities to the lubricant..
Effect of welding speed on microstructure and corrosion resistance of Al–Li alloy weld joint
Authors: Yang Mei , Lu Jingxiang , Chen Jing , Li Yang , Liu Yang , Yang Honglang
Published: August 2019

The corrosion resistance of a weld has a great impact on the service life of the joint. Changes in welding parameters can cause changes to the heat input, which affect the formation of the weld bead and the precipitation of the second phase, which determines the corrosion resistance of the weld. In this paper, the effect of a change in the welding speed on 2195 aluminium–lithium (Al–Li) alloy joints welded by laser and metal inert gas (laser‐MIG) hybrid welding using Al–Si welding wire was studied. The macrostructure and microstructure of the weld were characterized by optical microscopy, X‐ray diffraction, and scanning electron microscopy. The results show that the predominant precipitates in the laser‐MIG hybrid welded Al–Li alloy were the θ (Al2Cu) and T (Al–Li–Si) phases. As the welding speed increased from 11.5 mm/s to 16.5 mm/s, the heat input decreased, and the amount of the precipitated phase increased. Intergranular corrosion and electrochemical experiments were carried out on the weld seam, and the corrosion resistance was tested. With increasing welding speed, the corrosion resistance of the weld decreased. The high potential of the precipitated phase decreased the corrosion resistance of the weld joint.
Self‐Assembly of Nanoparticles in 2D and 3D: Recent Advances and Future Trends
Authors: Ghosh Sujit Kumar , Böker Alexander
Published: August 2019

For more than a century, it has been known that emulsions consisting of two immiscible liquids can be rendered from coalescence by means of solid particles, coined as Pickering emulsions. Based on this discovery, novel materials as a result of the formation of 2D and 3D assemblies of nanostructures at liquid–liquid interfaces have been synthesized. These materials have received considerable attention due to several unique attributes of the nanoscale materials within these assemblies and their utilization in a wide arena of niche applications. With the progressive advent of the synthetic strategies of the nanostructures, these assemblies can be engendered to create membranes and capsules with high mechanical strength and desirable porosity and even can be made stimuli‐responsive. The nanostructures, ranging from inorganic particles to proteins to polymeric architectures, possess their stabilizing effects due to excess attachment energies and lead to the maneuvering of exciting structural design, such as colloidosomes and yeastosomes. The ability of the different kind of particles at the nanoscale dimension to self‐assemble at the liquid–liquid interface into ordered superstructures has substantial potential toward the design of exotic electronic, catalytic, optical, magnetic, and biomimetic materials.
Block and Graft Copolymers Made of 16‐Membered Macrolactones and l‐Alanine: A Comparative Study
Authors: Tinajero‐Díaz Ernesto , Martínez de Ilarduya Antxon , Muñoz‐Guerra Sebastián
Published: August 2019

Block and graft poly(macrolactone)‐poly(α‐amino acid) copolymers made of l‐alanine and pentadecalactone or globalide respectively, are prepared. A sequential ring‐opening polymerization (ROP) copolymerization route consisting of two stages, the first devoted to the preparation of the amino‐functionalized poly(macrolactone) and the second to the amino‐initiated polymerization of l‐alanine N‐carboxyanhydride (Ala‐NCA), is followed for the synthesis of both types of copolymers. Poly(l‐alanine) segment lengths are accurately controlled by adjusting the macroitiator/Ala‐NCA ratio used for reaction in the second stage. Block copolymers are semicrystalline with the poly(pentadecalactone) block crystallizes well in a separate phase and the poly(α‐amino acid) block arranged in either the α‐helical or β‐sheet structure in a ratio that is depending on composition and temperature. Graft copolymers are amorphous but with the poly(α‐amino acid) side chains arranged in a more or less regular conformation. Nanoparticles with a diameter of around 300 nm and moderate positive Z‐potential can be obtained from the block copolymers by self‐assembling in water whereas graft copolymers are unable to render recognizable objects of nanometer‐dimension under similar conditions.
ICAR ATRP Polymerization‐Induced Self‐Assembly Using a Mixture of Macroinitiator/Stabilizer with Different Molecular Weights
Authors: Cao Mengya , Zhang Yixiang , Wang Jian , Fan Xiaoshan , Wang Guowei
Published: August 2019

The poly[oligo(ethylene oxide) methyl ether methacrylate]s, POEOMA24 and POEOMA78 with average degree of polymerization (DP) of 24 and 78, respectively, are separately achieved by initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) of OEOMA300 monomer. The mixtures of [POEOMA24]0/[POEOMA78]0 = 1/1, 2/1, or 4/1 are employed as macroinitiator/stabilizer to practice the ICAR ATRP polymerization‐induced self‐assembly (PISA) of benzyl methacrylate (BnMA) at 65 °C. When the obtained dispersions are sequentially cooled to room temperature, diluted into ethanol, and observed by transmission electron microscopy (TEM) measurement, the cases of [POEOMA24]0/[POEOMA78]0 = 1/1 or 2/1 and target DPPBn
MA = 100 or 200 lead to nanoparticles with irregular sizes, while the cases of [POEOMA24]0/[POEOMA78]0 = 4/1 and target DPPBn
MA = 300 give the regular ones. When the obtained dispersions at a high temperature (65 °C) are directly diluted into room temperature ethanol and observed by TEM, nanoparticles with light contrast but clear contour can be observed. The results show that the higher content of POEOMA78 tends to improve the solubility of diblock copolymer and thus leads to insufficient stabilization of the nanoparticles. The morphological difference from the room‐temperature and 65 °C dispersions help elucidate the intrinsic character of the PISA system.
Thermally Induced Reversible Self‐Assembly of Apoferritin–Block Copolymer Complexes
Authors: Korpi Antti , Skumial Piotr , Kostiainen Mauri A.
Published: August 2019

Protein cages are interesting building blocks for functional supramolecular assemblies. A multi‐responsive system composed of apoferritin and thermo‐responsive block copolymers complexed through electrostatic interactions is described here. The polymers are linear chains with cationic and thermo‐responsive blocks, and both diblock and triblock copolymers are studied. The apoferritin can be reversibly assembled and disassembled in aqueous solutions by altering the temperature and electrolyte concentration of the solutions. The control over the conditions is straightforward and all the components can be recovered, offering a potential alternative for systems requiring chemical or genetic modification of proteins.
Parity Violation in Supramolecular Aggregation: Insights from Optoelectronic Properties
Authors: Chal Pousali , Shit Arnab , Nandi Arun K.
Published: August 2019

In the contemporary science, it is believed that supramolecular chiral structures (left‐ or right‐handed) emanating from enantiomeric (L‐ or D‐enantiomers) chiral building blocks would have identical physical and chemical properties. Here, PBI derivatives with chiral L‐phenylalanine and D‐phenylalanine at the imide positions have been synthesized and designated as PPAL and PPAD. Surprisingly, the chiral perylenebisimide (PBI) derivatives containing PPAL and PPAD self‐assemble to mirror image helical supramolecular structures showing dissymmetric energy states. They also exhibit different optoelectronic characteristics in the supramolecular aggregated state in chlorinated solvents. These studies indicate parity violation in supramolecular aggregated state and it may provide great impetus in understanding the origin of the evolutionary conserved L‐amino acids in nature.
Performances of PCL/PVC/Organoclay Nanobioblends Films for Packaging Applications
Authors: Hadj‐Hamou Assia Siham , Yahiaoui Farida
Published: August 2019

A series of antimicrobial PCL/PVC/OMMTs nanobioblends films are successfully prepared via melt blending process of the poly (ϵ‐caprolactone) (PCL), poly (vinyl chloride) (PVC), and three different clay types namely Cloisite 30B (C30B), trimethylhexadecyl ammonium (OMMT1), and cetylpyridinium chloride monohydrate (OMMT2) modified montmorillonite. All the PCL/PVC/OMMTs nanocomposites display mixed intercalated/partially exfoliated structures as attested by X‐Ray Diffraction and Transmission Electron Microscopy. Glass transition, fusion and cristallization of these nanomaterials are studied using differential scanning calorimetry (DSC). The organoclay effect on the mechanical, barrier and antimicrobial properties is investigated. The results confirm that the insertion of 3 wt% of OMMT (whatever its intercalant agent nature) into the PCL/PVC matrix leads to (1) a remarkable improvement in barrier properties, (2) an interesting enhancement in mechanical properties, and (3) a strong antimicrobial activity against Staphylococcus aureus (Gram‐positive) and Escherichia coli (Gram‐negative).
Hierarchical Nanotube Self‐Assembly of DNA Minor Groove‐Binding Ligand DB921 via Alkali Halide Triggering
Authors: Mizuta Ryo , Devos Juliette M. , Narayanan Theyencheri , Oliva Mizar , Gray Melissa , Webster Jessica , Ling Wai‐Li , Round Adam , Munnur Deeksha , Mossou Estelle , Farahat Abdelbasset , Boykin David W. , Wilson W. David , Neidle Stephen , Schweins Ralf , Rannou Patrice , Haertlein Michael , Forsyth V. Trevor , Mitchell Edward
Published: August 2019

A systematic study into a novel self‐assembling system is presented whereby the small molecule DB921 forms nearly monodisperse nanotubes upon addition of a suitable salt. Small‐angle X‐ray scattering and negative stain transmission electron microscopy are employed as the principal characterization methods to study both the fundamental assembly processes and reaction kinetics. The assembly is found to be hierarchical, culminating with helical winding of intermediate ribbon structures into nanotubes. The driving force for this process is likely the electrostatic interaction between DB921 and salt anions; this aspect can be used to control nanotube assembly and morphology.
Self‐Assembling Amyloid Sequences as Scaffolds for Material Design: A Case Study of Building Blocks Inspired From the Adenovirus Fiber Protein
Authors: Kokotidou Chrysoula , Tamamis Phanourios , Mitraki Anna
Published: August 2019

In the last two decades the study of the properties of biological self‐organization has created a separate area of research, ranging from biomedicine and biotechnology to materials science and nanotechnology. In particular, the design of self‐assembling protein and peptide building blocks is often achieved by drawing inspiration from natural fibrous proteins such as collagen, elastin, silk, and spider silks that are built up from repetitive sequences. Self‐assembling proteins and peptides are water soluble and biocompatible nanostructures formed spontaneously under mild conditions through non‐covalent interactions. They form supramolecular structures such as ribbons, nanotubes, and fibers. The wide range of chemical functionalities found in peptides (i.e., 20 amino acids) enables the design and engineering of specific interactions with target materials for potential technological applications. Moreover, with the aid of computational methods, tailor made modifications can be inserted for the «on‐demand» design of functional amyloid materials binding to ions or compounds. Technologically, the self‐organized structures can be used as templates for the growth of inorganic materials, such as metallic nanoparticles (silver, gold, and platinum), silica, calcium phosphates etc. Self‐assembling peptides may also create hydrogels and entangled fibrous networks that can be used as scaffolds for attachment, growth and proliferation of living cells, allowing tissue repair and engineering. In this short review we summarize the progress made in the field with emphasis on our progress on how to translate fundamental structural knowledge from the adenovirus fiber protein into self‐assembling nanomaterials targeted for novel applications.
Synergistic Sorption of Mixed Solvents in Wood Cell Walls: Experimental and Theoretical Approach
Authors: Aguilera‐Segura Sonia Milena , Bossu Julie , Corn Stéphane , Trens Philippe , Mineva Tzonka , Le Moigne Nicolas , Di Renzo Francesco
Published: August 2019

The behavior of poplar wood and its components in water‐ethanol mixtures is investigated through a coupled experimental and theoretical approach including physico‐chemical and dynamic mechanical analyses and molecular dynamics simulations. Affinity for water‐ethanol vapors, measured by isothermal gravimetric sorption experiments, features a maximum for mixed vapors. The longitudinal viscoelastic behavior of the same wood upon immersion in ethanol‐water solutions, measured by dynamic mechanical analysis, features a minimum in storage modulus and a maximum damping upon immersion in solutions of intermediate composition. Optical microscopy observation of solvent‐saturated samples evidences inter‐ and intra‐cellular disbonding in pure ethanol and ethanol aqueous solutions. Molecular dynamics simulations provide information on interactions of water‐ethanol solutions with models of cellulose microfibers and lignin. The relative solvation of cellulose microfibers by water and ethanol shows a nearly linear variation with the composition of the solution. In contrast, the accessibility of lignin dimers to the solvent presents a maximum at intermediate ethanol concentrations, in correspondence with a conformational transition of the dimer towards an extended conformation. The modelization of the interactions of cellulose and lignin in water‐ethanol solutions indicates a minimum of adhesion of the two components of wood in the presence of solutions with intermediate concentrations.
Market structure determinants of performance for independent supermarkets
Authors: Volpe Richard , Cho Clare
Published: August 2019

We create a novel dataset by merging Nielsen TDLinx data with the results of a survey of supermarket managers. We study the determinants of store performance for independent supermarkets, as measured by sales per square foot, paying particular attention to local market structure. The results show a negative and significant impact of market concentration on independent supermarket performance, which is robust to model specification. We also identify a number of format‐specific impacts and performance drivers such as store characteristics, all of which motivate future research.
Existence and uniqueness of solutions for nonlinear Volterra‐Fredholm integro‐differential equation of fractional order with boundary conditions
Authors: Laadjal Zaid , Ma Qing‐Hua
Published: August 2019

In this paper, we established some results concerning the existence and uniqueness of a nonlinear Volterra‐Fredholm integro‐differential equation of Caputo fractional order subject to the boundary value conditions. These new results are obtained by applying standard fixed point theorems. An example is presented to illustrate our main result.
Dual‐band reconfigurable coding metasurfaces hybridized with vanadium dioxide for wavefront manipulation at terahertz frequencies
Authors: Wang Hongjun , Deng Li , Zhang Chen , Qu Meijun , Wang Ling , Li Shufang
Published: August 2019

In this article, we propose a frequency reconfigurable reflective coding metasurface hybridized with vanadium dioxide (VO2) meta‐atoms for wavefront manipulation at terahertz (THz) frequencies using the Pancharatnam‐Berry (PB) phase principle. At room temperature, the meta‐atoms can achieve a nearly constant 180° reflection phase difference illuminated by linearly x‐ and y‐polarized waves while maintaining almost consistent reflection amplitude within 3.76 to 3.84 THz, corresponding to the conductivity of . Once the temperature is increased and VO2 is in a fully metallic state with the conductivity of , the meta‐atoms operate at 1.18 to 1.47 THz. Flexible controls of scattering patterns of the PB coding metasurface can be realized utilizing the meta‐atoms. Numerical simulations demonstrate that the designed VO2‐based metasurface can generate multibeams as expected. This work opens a pathway in designing frequency reconfigurable coding metasurface to generate multibeams in THz, which holds great potential in new concept antennas for future wireless communication systems.
A compact planar antenna with extended patch and truncated ground plane for ultra wide band application
Authors: Baudha Sudeep , Basak Amartya , Manocha Mayank , Yadav Manish V.
Published: August 2019

In this article, a compact broadband planar monopole microstrip patch antenna with extended patch and a truncated ground plane is proposed for ultra‐wideband application. The optimal dimensions of the proposed antenna are 20 × 20 × 1.6 mm3. The proposed antenna is fabricated on FR4 substrate that is a low‐cost commercially available substrate with εr = 4.3 and a loss tangent of 0.025. The impedance bandwidth (defined by the magnitude of S11 less than −10 dB) of the proposed antenna is 127% (3.13‐14.07 GHz). The peak gain and radiation efficiency of the proposed antenna are 3.4 dB and 78%, respectively. The proposed antenna exhibits a stable radiation pattern at the operating band. The simulated results of the proposed antenna are observed to be in agreement with the measured results when fabricated. The proposed antenna supports various frequency bands such as ultra‐wideband, 3.5/5.5 GHz WiMAX bands, 5.2/5.8 GHz WLAN bands, X Band (8‐12 GHz), satellite communication, and other wireless communication services. The proposed design and its various results have been discussed in further detail.
Simple method for computing scattered radiation in breast tomosynthesis
Authors: Diaz Oliver , Elangovan Premkumar , Young Kenneth C. , Wells Kevin , Dance David R.
Published: August 2019

Purpose

Virtual clinical trials (VCT) are a powerful imaging tool that can be used to investigate digital breast tomosynthesis (DBT) technology. In this work, a fast and simple method is proposed to estimate the two‐dimensional distribution of scattered radiation which is needed when simulating DBT geometries in VCTs.

Methods

Monte Carlo simulations are used to precalculate scatter‐to‐primary ratio (SPR) for a range of low‐resolution homogeneous phantoms. The resulting values can be used to estimate the two‐dimensional (2D) distribution of scattered radiation arising from inhomogeneous anthropomorphic phantoms used in VCTs. The method has been validated by comparing the values of the scatter thus obtained against the results of direct Monte Carlo simulation for three different types of inhomogeneous anthropomorphic phantoms.

Results

Differences between the proposed scatter field estimation method and the ground truth data for the OPTIMAM phantom had an average modulus and standard deviation of over the projected breast area of 2.4 ± 0.9% (minimum −17.0%, maximum 27.7%). The corresponding values for the University of Pennsylvania and Duke University breast phantoms were 1.8 ± 0.1% (minimum −8.7%, maximum 8.0%) and 5.1 ± 0.1% (minimum −16.2%, maximum 7.4%), respectively.

Conclusions

The proposed method, which has been validated using three of the most common breast models, is a useful tool for accurately estimating scattered radiation in VCT schemes used to study current designs of DBT system.
Using Side-Scan Sonar and N-Mixture Modeling to Estimate Atlantic Sturgeon Spawning Migration Abundance
Authors: Vine Joshua R. , Kanno Yoichiro , Holbrook S. Chad , Post William C. , Peoples Brandon K.
Published: August 2019

Understanding the relationship between number of spawners and recruitment is essential for managing fish populations. Atlantic Sturgeon Acipenser oxyrinchus (ATS) are endangered anadromous fish inhabiting the rivers, estuaries, and marine environments along the Atlantic coast of North America. Atlantic Sturgeon are periodic life history strategists that exhibit both spring and fall spawning migrations. Traditional capture–mark–recapture techniques can be used to estimate spawning run abundance but are resource intensive and potentially stressful on migrating individuals. Noninvasive methods, such as side-scan sonar, can be a less stressful alternative to estimating abundance. We sampled the uppermost portion of the Savannah River, USA, over 50 occasions from August to November 2017 using side-scan sonar. Bayesian N-mixture modeling was used to estimate spawner abundance and covariate effects based on spatially and temporally replicated count data obtained from sonar recordings. We detected at least one ATS on each sampling occasion and estimated a maximum daily spawner abundance between 35 and 55 individuals (95% credible interval) within the sampled area during the 2017 fall spawning season. Maximum discharge significantly affected ATS detection, and site average maximum depth significantly affected ATS abundance. Our results suggest that side-scan sonar can be used as an alternative to traditional mark–recapture techniques for spawner abundance estimation. Routine sampling by using our methods will efficiently produce spawning run estimates and provide insight regarding the effects of environmental covariates on spawner abundance seasonally.
Optimizing acquisition and fitting conditions for 1H MR spectroscopy investigations in global brain pathology
Authors: Hoefemann Maike , Adalid Victor , Kreis Roland
Published: August 2019

Purpose

To optimize acquisition and fitting conditions for nonfocal disease in terms of voxel size and use of individual coil element data. Increasing the voxel size yields a higher signal‐to‐noise ratio, but leads to larger linewidths and more artifacts. Several ways to improve the spectral quality for large voxels are exploited and the optimal use of individual coil signals investigated.

Methods

Ten human subjects were measured at 3 T using a 64‐channel receive head coil with a semi‐LASER localization sequence under optimized and deliberately mis‐set field homogeneity. Eight different voxel sizes (8 to 99 cm3) were probed. Spectra were fitted either as weighted sums of the individual coil elements or simultaneously without summation. Eighteen metabolites were included in the fit model that also included the lineshapes from all coil elements as reflected in water reference data. Fitting errors for creatine, myo‐Inositol and glutamate are reported as representative parameters to judge optimal acquisition and evaluation conditions.

Results

Minimal Cramér‐Rao lower bounds and thus optimal acquisition conditions were found for a voxel size of ~ 70 cm3 for the representative upfield metabolites. Spectral quality in terms of lineshape and artifact appearance was determined to differ substantially between coil elements. Simultaneous fitting of spectra from individual coil elements instead of traditional fitting of a weighted sum spectrum reduced Cramer‐Rao lower bounds by up to 17% for large voxel sizes.

Conclusion

The optimal voxel size for best precision in determined metabolite content is surprisingly large. Such an acquisition condition is most relevant for detection of low‐concentration metabolites, like NAD+ or phenylalanine, but also for longitudinal studies where very small alterations in metabolite content are targeted. In addition, simultaneous fitting of single channel spectra enforcing lineshape and coil sensitivity information proved to be superior to traditional signal combination with subsequent fitting.
Food management of early introduced caprine and bovine herds in the early Neolithic site of La Draga (Banyoles): An isotopic approach
Authors: Navarrete Vanessa , Tornero Carlos , Balasse Marie , Saña Maria
Published: August 2019

The arrival of early farmers and their livestock in the western Mediterranean during the early Neolithic marked a new way of life for the north‐east Iberian Peninsula. Given the permanence of the introduced economic strategies, which are still practiced today, and their apparently momentous outcome, this process has generally been explained as a success. The introduction of livestock must have played a fundamental role, but we know little about how these newly arrived domestic animals were managed. In this sense, the management of food habits of domestic animals could be a key factor to understand the success of different herding systems during the introduction and adaptation of domesticates in the Iberian Peninsula. Sequential analyses of δ13C and δ18O values in tooth enamel crowns are here used to provide detailed information about dietary inputs of early caprine and bovine herds introduced into the Iberian Peninsula. Our study was carried out at La Draga (5314–5209 cal BC), a site on the eastern side of Lake Banyoles (Girona, NE Iberian Peninsula). Data show that caprine and bovine herds were fed with variable foddering strategies. Sheep reflect feeding in the swamps or on forest resources with reduced seasonal dietary changes. Goat and cattle herds display food habits that could involve foddering on stored agricultural by‐products during specific season times, probably linked to reproductive and productive strategies. This information helps to reconstruct how these early Neolithic communities found the way to success in the new territories of the western Mediterranean.
Electrospun hyperbranched polylactic acid–modified cellulose nanocrystals/polylactic acid for shape memory membranes with high mechanical properties
Authors: Peng Qingyuan , Cheng Jingzhen , Lu Shaorong , Li Yuqi
Published: August 2019

The polylactic acid (PLA) nanofiber membranes reinforced with hyperbranched PLA‐modified cellulose nanocrystals (H‐PLA‐CNCs) were prepared by electrospinning. The H‐PLA‐CNCs and the nanofiber membranes were researched by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The outcomes embodied that the cellulose nanocrystals (CNCs) could be successfully improved by the hyperbranched PLA, which would offer powerful CNCs/matrix interfacial adhesion. Thus, the mechanical and shape memory properties of PLA can be improved by adding the H‐PLA‐CNCs. In particular, when the addition of H‐PLA‐CNCs was 7 wt%, the tensile strength and an ultimate strain of PLA composite nanofiber membranes was 15.56 MPa and 25%, which was 228% and 72.4% higher than that of neat PLA, respectively. In addition, the shape recovery rate of the PLA/5 wt% H‐PLA‐CNCs composite nanofiber membrane was 93%, which was 37% higher than that of neat PLA. We expected that this present study would provide unremitting efforts for the development of more effective approaches to prepare biology basic shape memory membranes with high mechanical properties.
Prenatal enzymatic diagnosis of lysosomal storage diseases using cultured amniotic cells, uncultured chorionic villus samples, and fetal blood cells: Hacettepe experience
Authors: Unal Canan , Ozkara Hatice Asuman , Tanacan Atakan , Fadiloglu Erdem , Lay Incilay , Topçu Meral , Cakar Ayse Nur , Beksac Mehmet Sinan
Published: August 2019

Aim

To evaluate the results of prenatal enzymatic diagnostic studies for detecting lysosomal storage diseases (LSDs) during 1992 to 2018.

Methods

Pregnancies subjected to “prenatal enzymatic diagnosis of LSDs” during 1992 to 2018 were retrospectively evaluated in terms of invasive prenatal tests, type of LSDs, and obstetric outcomes.

Results

A total of 142 pregnancies were evaluated for various types of LSDs of which 30, 103, and 9 cases were subjected to amniocentesis, chorionic villus sampling, and fetal blood sampling, respectively. Retrospective analysis of prenatal diagnosis revealed that LSDs affected 33% (47/142) of the fetuses. Sandhoff disease (28%), Tay‐Sachs disease (27%), and metachromatic leukodystrophy (MLD) (20%) were the most frequent LSDs among the evaluated cases with two false negatives, one each for Tay‐Sachs disease and MLD.

Conclusion

Enzymatic prenatal diagnoses of certain LSDs may serve as a primary intervention point for families with index cases of infantile or late infantile types of LSDs, since they are associated with poor outcomes, including mortality. In addition, enzyme studies alone may also be feasible for populations with increased risk of molecular heterogeneity, novel mutations, and low‐income settings where genetic analysis is inaccessible.