bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictions of Thermo‐Mechanical Properties of Cross‐Linked Polyacrylamide Hydrogels Using Molecular Simulations
Authors: An Meng , Demir Baris , Wan Xiao , Meng Han , Yang Nuo , Walsh Tiffany R.
Published: January 2019

Hydrophilic acrylamide‐based hydrogels are emerging platforms for numerous applications, but the resources to fully exploit these materials are currently limited. A deep understanding of the molecular‐level structure/property relationships in hydrogels is crucial to progressing these efforts. Such relationships can be challenging to elucidate on the basis of experimental data alone. Here, molecular simulations are used as a complementary strategy to reveal the molecular‐level phenomena that govern the thermo‐mechanical properties of hydrogels. The focus is on acrylamide‐based hydrogels cross‐linked with N,N′‐methylenebisacrylamide, generated using previously established computational cross‐linking procedure. The water content is found to be a key determinant in the elastic response of these hydrogels, with enhanced tensile and shear properties at low water content. However, it is also found that increasing water content enhances the hydrogel's thermal conductivity, with the dominant contribution arising from the non‐bonded contributions to the heat flux. In addition, chemical cross‐linking improves the heat transfer properties of the hydrogel, whereas a reduction in convective heat transfer is predicted with an increase in hydrogel cross‐linking. These simulations provide a rational basis for designing and testing customized hydrogel formulations for maximizing both thermal conductivity and mechanical properties.
Bridging two‐liquid theory with molecular simulations for electrolytes: An investigation of aqueous NaCl solution
Authors: Saravi Sina H. , Ravichandran Ashwin , Khare Rajesh , Chen Chau‐Chyun
Published: January 2019

We reexamine the theoretical framework of electrolyte nonrandom two‐liquid model and formulate the binary interaction parameters as functions of species diameter (
σ), effective interaction strength (
ɛ), the domain radius around the center species (
R), and the nonrandomness factor (
α). We show that these quantities can be directly obtained from molecular simulations using aqueous NaCl as the model system. The binary interaction parameters determined from the simulations are consistent with those obtained from regression of experimental data. Our work provides a molecular interpretation of the classical thermodynamic model and shows a way to predict from molecular simulations the binary interaction parameters for use in process industries. © 2019 American Institute of Chemical Engineers AIChE J, 65: 1315–1324, 2019
Hydrothermal reaction of K‐feldspar powder in NaOHCa (OH)2 mixed medium
Authors: Liu Changjiang , Ma Hongwen , Gao Yuan
Published: January 2019

The hydrothermal reactions between K‐feldspar powder and NaOHCa (OH)2 mixed alkaline medium at 240°C were investigated. The effects of Na ratio (xNa, Na2O/(Na2O + CaO) in mole) on the phase and composition change in solid products were explored in detail. Results showed that increase in xNa led to the orderly formation of compounds following the sequence of CaOSiO2H2O → Na2OCaOSiO2H2O → Na2OAl2O3SiO2H2O, and K+ was accessible into solution after reaction. The new products after reaction was tobermorite, pectorite, nepheline hydrate, analcime, and hydroxycancrinite, depending on different xNa. The hydrothermal reaction was deduced to be a coupled dissolution and reprecipitation process, which was governed by the chemical equilibrium with the change in solution chemistry.
Chemical structure modifications and nano‐technology applications for improving ADME‐Tox properties, a review
Authors: Farouk Faten , Shamma Rehab
Published: January 2019

The chemical structure of a drug molecule affects its physicochemical properties and subsequent biological activities. Many pharmacologically active molecules fail to reach the market or have an inconvenient route of administration due to their chemical structure. This is especially important with the recent tendency to develop drug candidates beyond the drug‐likeness space for addressing difficult targets such as protein–protein interfaces. The objective of this review is to discuss chemical and pharmaceutical approaches for circumventing structure‐related problems and achieving acceptable ADME‐Tox properties. The chemical structure‐associated limitations are critically discussed. Chemical modifications and pharmaceutical technology applications for improving drug‐likeness are illustrated. Attention is paid to modern therapeutic candidates and targets. In conclusion, chemical modifications as well as nanotechnology applications can be used effectively to enhance absorption, permeability, and selective distribution to a body compartment, to improve drug specificity, to limit off‐target toxicity as well as to enhance stability and to protect against metabolism. The nano‐technology‐based solutions are relatively easier to develop over a new molecular entity, but adopting the chemical approach is more established in terms of safety, quality control, and regulatory assessment methods.
Subject English as citizenship education
Authors: Belas Oliver , Hopkins Neil
Published: January 2019

This article is equal parts educational history and political philosophy. We aim to remind readers that subject English (SE) and indeed state education emerge from the contradictory impulses of classical liberalism, and that, more than simply resembling citizenship education, SE emerges in the first instance as a form of highly normativising citizenship education. We further argue that, following England's recent educational reforms initiated by former Education Secretary Michael Gove, SE continues to be framed in moral terms consistent with citizenship education—again, of a highly normativising sort. England's current educational policy generally, and specifically the framing of SE, employs the language of liberal possibility, while ultimately espousing an invidious exclusionary and assimilationist politics. The framing of SE, moreover, is one that misrepresents the supposedly ‘rich and varied literary heritage’ it is supposed to exemplify and promote. The current political landscape in which the study of literature takes place is one where a crisis of liberalism is manifest (in terms of populism, radicalisation or apathy). However, we do not believe the answer is to retreat into a sealed, hermetic canon that excludes the reality that England and English literature are fundamentally multicultural and polyethnic. SE will be the poorer for not fully acknowledging and embodying this, for not enabling students to imaginatively and critically engage with characters and experiences that reflect both the present and long‐standing diversity of English society, as well as its present and long‐standing inequalities.
Knockdown of LncRNA GHET1 suppresses prostate cancer cell proliferation by inhibiting HIF‐1α/Notch‐1 signaling pathway via KLF2
Authors: Zhu Yanfeng , Tong Yue , Wu Jianhua , Liu Yuejuan , Zhao Mingjia
Published: January 2019

Prostate cancer (PC) is one of the most common cancers in male groups worldwide. Long noncoding RNAs (LncRNAs) are reported to be dysregulated in a variety of cancers, including PC. This study aimed to explore the role of LncRNA GHET1 in the pathogenesis of PC. RT‐qPCR was carried out to examine the relative expression level of GHET1 in PC patients. In vitro, GHET1 siRNA (si‐GHET1) was used to investigate the biological role of GHET1 in PC cell lines. Cell proliferation was detected by CCK‐8 and colony formation assay, while cell cycle and cell apoptosis were analyzed using flow cytometry. Moreover, western blot was carried out to measure the protein expression levels of KLF2 and HIF‐1α/Notch‐1 signal pathway. We found that GHET1 showed higher expression in PC tissues and had a negative correlation with KLF2 expression. Knockdown of GHET1 significantly suppressed the cell proliferation, induced cell cycle arrest at G0/G1 phase and promoted cell apoptosis. Additionally, si‐GHET1 transfection induced KLF2 upregulation and HIF‐1α/Notch‐1 signal pathway suppression, which could be rescued by si‐KLF2 transfection. These results suggest the key role of GHET1 in PC progression. Moreover, GHET1 might be explored to be a potential target for clinical treatment of PC. © 2019 BioFactors, 45(3):364–373, 2019
Occupational class and male cancer incidence: Nationwide, multicenter, hospital‐based case–control study in Japan
Authors: Zaitsu Masayoshi , Kaneko Rena , Takeuchi Takumi , Sato Yuzuru , Kobayashi Yasuki , Kawachi Ichiro
Published: January 2019

Little is known about socioeconomic inequalities in male cancer incidence in nonwestern settings. Using the nationwide clinical and occupational inpatient data (1984‐2016) in Japan, we performed a multicentered, matched case–control study with 214 123 male cancer cases and 1 026 247 inpatient controls. Based on the standardized national classifications, we grouped patients’ longest‐held occupational class (blue‐collar, service, professional, manager), cross‐classified by industrial cluster (blue‐collar, service, white‐collar). Using blue‐collar workers in blue‐collar industries as the referent group, odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by conditional logistic regression with multiple imputation, matched for age, admission date, and admitting hospital. Smoking and alcohol consumption were additionally adjusted. Across all industries, a reduced risk with higher occupational class (professionals and managers) was observed for stomach and lung cancer. Even after controlling for smoking and alcohol consumption, the reduced odds persisted: OR of managers in white‐collar industries was 0.80 (95% CI 0.72‐0.90) for stomach cancer, and OR of managers in white‐collar industries was 0.66 (95% CI 0.55‐0.79) for lung cancer. In white‐collar industries, higher occupational class men tended to have lower a reduced risk for most common types of cancer, with the exception of professionals who showed an excess risk for prostate cancer. We documented socioeconomic inequalities in male cancer incidence in Japan, which could not be explained by smoking and alcohol consumption.
Harnessing the Chemistry of the Indole Heterocycle to Drive Discoveries in Biology and Medicine
Authors: Norwood Verrill M. , Huigens Robert W.
Published: January 2019

Indole‐containing compounds demonstrate an array of biological activities relevant to numerous human diseases. The biological activities of diverse indole‐based agents are driven by molecular interactions between indole agent and critical therapeutic target. The chemical inventory of medicinally useful or promising indole compounds spans the entire structural spectrum, from simple synthetic indoles to highly complex indole alkaloids. In an analogous fashion, the chemistry behind the indole heterocycle is unique and provides rich opportunities for extensive synthetic chemistry, enabling the construction and development of novel indole compounds to explore chemical space. This review will present heterocyclic chemistry of the indole nucleus, indole compounds of clinical use, complex indole alkaloids and indole‐inspired discovery efforts by multiple research groups interested in using novel indole‐containing small molecules to drive discoveries in human biology and medicine.
Working with prisoners who self‐harm: A qualitative study on stress, denial of weakness, and encouraging resilience in a sample of correctional staff
Authors: Smith Hayden P. , Power Jenelle , Usher Amelia M. , Sitren Alicia H. , Slade Karen
Published: January 2019

Background

Rates of self‐harm are high among prisoners. Most research focuses on the vulnerable prisoner, and there is little on the impact of these behaviours on staff.

Aims

To investigate staff perceptions of self‐harming behaviours by prisoners, including their views on its causes, manifestation, prevention in institutions, and impact on them.

Methods

Semistructured interviews were conducted with 20 administrative and 21 therapeutic prison staff who are responsible in various ways for prisoners who self‐harm. Their narratives were explored using interpretative phenomenological analysis.

Results

Despite prison staff being experienced with prisoners' self‐harming behaviours, including severe acts of self‐harm, they were apt to reject any negative impact on their own mental health or well‐being. This denial of negative impact was accompanied by perceptions of the inmate's actions being manipulative and attention seeking. Prison staff also perceived institutional responses to self‐harming behaviours by prisoners as being mixed, ambiguous, or showing preference for relying on existing suicide protocols rather than task‐specific guidance.

Conclusions

Although staff gave explanations of prisoner self‐harm in terms of “manipulative behaviour,” prisoners' self‐harm is, in fact, complex, challenging, and often severe. This staff perception may reflect denial of impact of often distressing behaviours on them personally and their own coping mechanisms. This could be feeding in to a perceived lack of clear and effective institutional responses to the self‐harm, so further research is needed to determine how staff could broaden their views, and respond more effectively to prisoners. Psychologically informed group work and/or reflective practice are among the candidates for such help for staff.
N‐Doped Hierarchical Porous Carbon with Open‐Ended Structure for High‐Performance Supercapacitors
Authors: Cao Shubo , Qu Ting , Zhang Ang , Zhao Yongbin , Chen Aihua
Published: January 2019

N‐doped hierarchical porous carbon with an open‐ended nanostructures were prepared through activating hollow carbon spheres (HCS), which were synthesized by using the self‐assembled amphiphilic block copolymer polystyrene‐b‐poly(4‐vinyl pyridine) (PS‐b‐P4VP) as template and pyrrole as carbon and nitrogen source. Through chemical activation with KOH, the original close‐ended HCS became open‐ended nanostructures (denoted as A‐HCS). This unique structure possesses several important properties as electrode for application in supercapacitors: (a) large surface area (1583 m2/g) and pore volume (3.82 cm3/g), (b) hierarchical porous carbon with small size (<100 nm) and thin curved walls (thickness <20 nm), (c) high N content (6.73 at%). Compared with the close‐ended HCS, the open‐ended A‐HCS exhibits better performance. The A‐HCS electrode presents a high specific capacitance (284 F/g at 0.2 A/g), good rate capability (70 % retention as the current density increased from 0.2 to 30 A/g), and superior cycling stability (96 % retention after 5000 cycles at 10 A/g). These results demonstrate that the N‐doped hierarchical porous carbon material with open‐ended nanostructure represents an alternative promising candidate as an efficient electrode material for supercapacitors.
Experimental investigation of dynamic asphaltene adsorption on calcite packs: The impact of single and mixed‐salt brine films
Authors: Monjezi Reza , Ghotbi Cyrus , Jafari Behbahani Taraneh , Bakhshi Puyan
Published: January 2019

In this study, the dynamic adsorption of asphaltene on a calcite surface is investigated. This study investigates the effect of mixed‐salt brines on asphaltene adsorption. The results of this work can facilitate the understanding of the complex wettability behaviour of carbonate reservoirs. All experiments were performed in porous media, which were sand‐packs filled with calcite powder, to study the influence of the type and concentration of salt on adsorption. The experiments were conducted with asphaltene concentration of 500 mg/L for brines of NaCl, Na2SO4, and a mixture of the two at various ionic strengths. In addition, two tests were performed with an asphaltene concentration of 2000 mg/L to observe the effect of increasing the asphaltene concentration on the adsorption. Moreover, the impact of brine film on asphaltene adsorption was investigated by conducting an additional experiment without brine saturation. The results show that by increasing the ionic strength, asphaltene adsorption increased at first owing to the reduction of electrostatic forces, then it reached its maximum, and it finally decreased as a result of the rise in the hydration force. The results show that in the presence of Na2SO4 brine, the asphaltene adsorption is more than that of the NaCl brine. For the mixed‐salt brine, as the ionic strength was increased, the asphaltene adsorption decreased at first and then it became constant. Furthermore, quadrupling the initial asphaltene concentration increased the adsorption up to 3.4 times. Additionally, the presence of brine film reduced the asphaltene adsorption by ∼80 %.
An Overview, Advantages and Therapeutic Potential of Nonpeptide Positive Allosteric Modulators of Glucagon‐Like Peptide‐1 Receptor
Authors: Smelcerovic Andrija , Lazarevic Jelena , Tomovic Katarina , Anastasijevic Marija , Jukic Marko , Kocic Gordana , Anderluh Marko
Published: January 2019

Due to uncomfortable injection regimens of peptidic agonists of glucagon‐like peptide‐1 receptor (GLP‐1R), orally available nonpeptide positive allosteric modulators (PAMs) of GLP‐1Rs are foreseen as the possible future mainstream therapy for type 2 diabetes. Herein, current GLP‐1R PAMs are reviewed. Based on the effectiveness and in silico predicted physicochemical properties, pharmacokinetics, and toxicity, possible candidates for further development as oral drugs were selected. The suggestion is that GLP‐1R PAMs might be used orally alone or in combination with dipeptidyl peptidase‐4 (DPP‐4) inhibitors, which could offer an optimal treatment option next to metformin monotherapy in type 2 diabetes mellitus, or in a wider spectrum of indications. Quercetin acts as a GLP‐1R PAM and DPP‐4 inhibitor, and therefore, might be considered as a pioneering agent with a dual mechanism of action, in terms of GLP‐1R positive allosteric modulation and DPP‐4 inhibition for potentiating GLP‐1 dependent effects.
Targeting Asexual and Sexual Blood Stages of the Human Malaria Parasite P. falciparum with 7‐Chloroquinoline‐Based 1,2,3‐Triazoles
Authors: Wadi Ishan , Prasad Davinder , Batra Neha , Srivastava Kumkum , Anvikar Anupkumar R. , Valecha Neena , Nath Mahendra
Published: January 2019

Novel 4‐amino‐7‐chloroquinoline‐based 1,2,3‐triazole hybrids were synthesised in good yields by CuI‐catalysed Huisgen 1,3‐dipolar cycloaddition reactions of 2‐azido‐N‐(7‐chloroquinolin‐4‐ylaminoalkyl)acetamides with various terminal alkynes. These new hybrids were screened in vitro against asexual blood stages of the chloroquine‐sensitive 3D7 strain of P. falciparum. The most active compounds were further screened against asexual and sexual stages (gametocytes) of the chloroquine‐resistant RKL‐9 strain of P. falciparum. Although all compounds were less potent than chloroquine against the 3D7 strain, the three best compounds were appreciably more active than chloroquine against the RKL‐9 strain, displaying IC50 values of <100 nm, with one of them having an IC50 of 2.94 nm. Further, the lead compounds were gametocytocidal with IC50 values in the micromolar range, and were observed to induce morphological deformations in mature gametocytes. Most compounds demonstrated little or no cytotoxicity and exhibited good selectivity indices. The most active compounds represent promising candidates for further evaluation of their schizonticidal and gametocytocidal potential.
Grain Selection and Crystal Orientation in Single‐Crystal Casting: State of the Art
Authors: Raza Muhammad Huzaifa , Wasim Ahmad , Hussain Salman , Sajid Muhammad , Jahanzaib Mirza
Published: January 2019

The properties of single‐crystal superalloys depend highly upon crystallographic orientation and the selection of single crystal (SX) in directional solidification (DS) process. The assessment of SX selection and crystallographic orientation determines the mechanical properties of the casting. Generally, it is considered that the deviation from [001] orientation should be less than 10° for better mechanical properties. This article provides a quantitative literature review analyzing the experimental results of 30 papers that studied the effects of process parameters on crystal orientation and grain selection in SX‐casting process. Key parameters that control the SX casting during DS process include spiral selector parameters, starter block parameters, withdrawal rate, pouring temperature, and ceramic mold temperature. The analysis in this research provides a strong evidence to assist the standard operating range of each parameter. A lack of focus in the literature on alloys is found. A framework based on the key parameters is also proposed in this review.
Atomic‐Scale Direct Identification of Surface Variations in Cathode Oxides for Aqueous and Nonaqueous Lithium‐Ion Batteries
Authors: Byeon Pilgyu , Lee Hyeon Jeong , Choi Jang Wook , Chung Sung‐Yoon
Published: January 2019

The electrochemical (de)intercalation reactions of lithium ions are initiated at the electrode surface in contact with an electrolyte solution. Therefore, substantial structural degradation, which shortens the cycle life of cells, is frequently observed at the surface of cathode particles, including lithium–metal intermixing, phase transitions, and dissolution of lithium and transition metals into the electrolyte. Furthermore, in contrast to the strict restriction of moisture in lithium‐ion cells with nonaqueous organic electrolytes, electrode materials in aqueous‐electrolyte cells are under much more reactive environments with water and oxygen, thereby leading to serious surface chemical reactions on the cathode particles. The present article presents key results regarding structural and composition variations at the surface of oxide‐based cathodes in both high‐performance nonaqueous and recently proposed aqueous lithium‐ion batteries; in particular, focusing on direct atomic‐scale observations preformed by means of scanning transmission electron microscopy. Precise identification of surface degradation at the atomic level is thus emphasized because it can provide significant insights into overcoming the limitations of current lithium‐ion batteries.
On‐Site Purification of Copper‐Contaminated Vanadium Electrolytes by using a Vanadium Redox Flow Battery
Authors: Reynard Danick , Vrubel Heron , Dennison Christopher R. , Battistel Alberto , Girault Hubert
Published: January 2019

Corrosion of carbon‐based electrodes and bipolar plates is a major hurdle and can be a cause of failure in commercial vanadium redox flow batteries (VRFBs). Carbon corrosion was found to occur in a commercial VRFB (10 kW/40 kWh), whereby cracks through bipolar plates enabled the electrolyte to leach the copper current collectors at the end of the stacks, contaminating the entire electrolyte solution. In this work, the effects of copper contaminants on the operation of a VRFB were studied. A simple and effective procedure to identify copper contamination on‐site and to purify the electrolyte was developed. The process was used to purify large quantities (6000 L) of copper‐contaminated electrolytes to levels below 1 ppm.
An efficient clustering and load balancing of distributed cloud data centers using graph theory
Authors: Devi R. Kanniga , Murugaboopathi G.
Published: January 2019

The prime focus of the Cloud Service Providers is enhancing the service delivery performance of the distributed cloud data centers. The clustering and load balancing of distributed cloud data centers have significant impact on its service delivery performance. Hence, this paper models distributed cloud data center environment as a network graph and proposes a two‐phase cluster‐based load balancing (CLB) algorithm based on a graph model. The first phase proposes a Cloud Data Center Clustering algorithm to cluster the distributed cloud data centers based on their proximity. The second phase proposes a Client‐Cluster Assignment algorithm to perform uniform distribution of the client requests across the clusters to enable load balancing. To assess the performance, the proposed algorithms are compared with other K‐constrained graph‐based clustering algorithms namely, graph‐based K‐means and K‐spanning tree algorithms on a simulated distributed cloud data center environment. The experimental results reveal that the proposed CLB algorithm outperforms the compared algorithms in terms of the average clustering time, load distribution, and fairness index and hence improves the service delivery performance of the distributed cloud data centers.
Investigation of the antibacterial and antifungal activity of thiolated naphthoquinones
Authors: Wellington Kevin W. , Nyoka Nomgqibelo B. P. , McGaw Lyndy J.
Published: January 2019

The WHO has stated that antibiotic resistance is escalating to perilously high levels globally and that traditional therapies of antimicrobial drugs are futile against infections caused by resistant microorganisms. Novel antimicrobial drugs are therefore required. We report in this study on the inhibitory activity of the 1,4‐naphthoquinone‐2,3‐bis‐sulfides and 1,4‐naphthoquinone sulfides against two bacteria and a fungus to determine their antimicrobial properties. The 1,4‐naphthoquinone sulfides have potent activity with a minimum inhibitory concentration (MIC) of 7.8 μg/mL against Staphylococcus aureus (Gram +ve), an MIC of 23.4 μg/mL against the fungus, Candida albicans, which was better than that of Amphotericin B (MIC = 31.3 μg/mL), and against Escherichia coli (Gram −ve) an MIC of 31.3 μg/mL was obtained. The 1,4‐naphthoquinone had an MIC of 11.7 μg/mL against S. aureus and the 1,4‐naphthohydroquinone also had the same activity against E. coli.

Hit, Lead & Candidate Discovery
Using multiple data sources to investigate foraging niche partitioning in sympatric obligate avian scavengers
Authors: Byrne Michael E. , Holland Amanda E. , Turner Kelsey L. , Bryan A. Lawrence , Beasley James C.
Published: January 2019

As carrion feeders competing for a limited and ephemeral resource, avian scavengers are ideal model organisms to study mechanisms of niche partitioning. Previous work has focused on observations of species’ interactions at carcasses, and although fruitful, the inclusion of behavior beyond that at carcasses, such as movement patterns, could yield a more comprehensive understanding of mechanisms of foraging niche partitioning. Our goal was to assess how differences in physiological, morphological, and social characteristics between sympatric black vultures (Coragyps atratus) and turkey vultures (Cathartes aura) manifest interspecific variation in movement patterns, foraging habitats, and carcass use to reduce direct competition. Both species are obligate scavengers that co‐occur across much of the New World. Turkey vultures are solitary foragers with enhanced olfactory capabilities and wings optimized for energy‐efficient low‐altitude soaring. Black vultures are aggressive, heavier bodied, and forage socially. We assessed interspecific variation in carcass exploitation using experimental carcass trials encompassing a range of habitats, carcass sizes, and seasons, and used GPS telemetry to compare how soaring conditions influenced daily space use and diurnal patterns of movement activity for each species. Turkey vultures occurred more often at small (i.e., rabbit) carcasses, and those obscured by forest cover than black vultures, and were the first vultures recorded at 94% of carcasses visited by both species. Both species increased movement rates and daily ranges when soaring conditions were favorable; however, turkey vultures had higher travel rates regardless of soaring conditions. Our results suggest the olfactory sense of turkey vultures allows them to locate smaller and visually obscured carcasses more efficiently than black vultures, facilitated by wing morphology that allows them to forage over large areas efficiently. Socially foraging black vultures appear specialized at locating larger carcasses in open habitats, which does not require as much foraging flight as turkey vultures. Our study illustrates how inclusion of movement ecology into niche partitioning studies provides a more complete understanding of the mechanisms of coexistence in avian scavenger guilds. This approach may provide important information to guide conservation efforts, such as supplemental feeding, of imperiled vulture species.
A novel solution for real‐time wireless networks: Telehealth psychological services in rural area
Authors: Luitel P. , Alsadoon Abeer , Prasad P. W. C. , Al‐Janabi Shahd , Chapagain B. , Pham Linh , Hisham Alsadoon Omar
Published: January 2019

Telehealth psychological services is a time‐efficient and cost‐effective therapy solution for persons in rural areas. The high congestion resulting from these infrastructure issues, which includes low‐bandwidth wireless connections and channels prone to data loss, tends to increase video delays, thereby making real‐time video transmission during telehealth psychological services challenging. The purpose of this study is, hence, to enable the successful implementation of telehealth psychological services in rural areas by minimising end‐to‐end video transmission delay and improving bandwidth efficiency. Our proposed system uses a distortion‐aware TCP‐friendly adaptive congestion control algorithm that adapts the congestion window size according to path characteristics and quality. Indeed, evaluation results show that our algorithm—as compared to a reference—significantly improves peak signal‐to‐noise ratio and end‐to‐end delay; thus, suggesting that the adoption of an adaptive congestion window size in our system can improve network bandwidth efficiency and reduce information delay resulting from packet queuing and unnecessary packet loss. The outcome is successful high‐definition video transmission during telehealth psychological services.
Experimental studies on characteristics of fire whirl in a vertical shaft
Authors: Gao Zheming , Li Shusheng , Gao Ye , Chow Wan Ki
Published: January 2019

An internal fire whirl can be generated readily in a tall shaft model with appropriate gap width at one corner. Experimental study was carried out to investigate the relationship between the characteristics of an IFW and the corner gap width in a 9‐m‐tall vertical shaft model. The vertical shaft had a 2.1 m by 2.1 m square section with gasoline pool fire of different diameters burning inside. The gap width was varied to investigate its impact on fire whirl characteristics, such as flame development, swirling intensity, flame height, flame temperature, and heat release rate of the gasoline pool fire. Vigorous flame swirling motions were generated when the ratio of the gap width to the shaft section perimeter was within the range 0.16 to 0.21. From the flame streamline angle, it was observed that the swirling component was much stronger than buoyancy component near the bottom of burning region. The swirling component decreased and became roughly the same as buoyancy near the middle. Finally, it diminished to being much weaker than buoyancy near the top of the fire. These observations suggest that the Froude number Fr decreased from a large number to 1, and then continued to decrease to 0.
Electronic Raman scattering as a probe for investigating interactions between impurities in silicon
Authors: Stavrias N. , Spizzirri P.G. , Prawer S.
Published: January 2019

Electronic Raman scattering (ERS) is investigated as a probe for interactions between impurities in silicon. We report ERS measurements of donors (P, Sb, and As) and acceptors (B) at various concentrations and measurements at various illumination wavelengths. The difference between above and below indirect band gap measurement is discussed in terms of the difficulties of using ERS as a localised probe. We extend the previous literature on impurity interactions of Si:P in the bulk to include Sb and B and demonstrate that the perturbation of the observed ERS transition energy resulting from wavefunction overlap of nearest neighbours is opposite for donors and acceptors. Finally, we model the magnitude of the shift to the first order as a function of the mean impurity atom separation.
Phase transformations of bovine serum albumin: Evidences from Rayleigh‐Brillouin light scattering
Authors: Dmitriev A.V. , Vashchenkov V.E. , Fedoseev A.I. , Lushnikov S.G.
Published: January 2019

Rayleigh‐Brillouin light‐scattering studies of a high‐concentration solution of bovine serum albumin (BSA, pH = 7.45, C = 100 mg/ml) in a sodium phosphate buffer in the temperature range 300–370 K are presented. It is shown that the temperature dependences of relative changes in the Brillouin shift and half width at half maximum and intensity of the Brillouin doublet and intensity of Rayleigh components exhibit anomalies in the vicinity of 335, 345, and 363 K. Analysis of the literature data allowed us to construct a phase diagram showing a sequence of BSA phase transformations in the temperature range from 300 to 375 K and to correlate the anomalies in the scattering spectra to the regions of phase transformations. The anomalies in the behavior of the light‐scattering spectra in the vicinity of Tm = 335 K are attributable to the melting temperature and the formation of BSA self‐assembled aggregates. The formation of a phase with oriented β‐sheet rich mature fibrils at Tm < T < 347 K is confirmed by elastic light scattering experiments. This phase passes into a gel‐like phase in which the aggregates are rearranged and a polymer network, which is finally converted to a gel in the vicinity of 363 K is formed. Thus, the Rayleigh‐Brillouin scattering experiments demonstrated the evolution of the structure, which manifested itself in the anomalous temperature behavior of the intensities of the Rayleigh and Brillouin components in the light‐scattering spectra. The anomalous low‐frequency dynamics of the BSA solution at denaturing and transition into a gel phase was clearly observed in the anomalous Brillouin shift behavior in the vicinity of 335 and 363 К. The sequence of phase transformations in BSA at heating from 300 to 375 K in the phase diagram correlates well with the anomalies observed in the evolution of Rayleigh‐Brillouin light scattering.
Variation of heavy metal contamination between mushroom species in the Copperbelt province, Zambia: are the people at risk?
Authors: Chungu Donald , Mwanza Alstone , Ng'andwe Phillimon , Chungu Bertha Chitala , Maseka Kenneth
Published: January 2019

BACKGROUND

Heavy metal contamination in mushrooms and the associated health risk are unknown in Zambia. We studied seven heavy metals and 23 mushroom species and interviewed 400 people.

RESULTS

Mushrooms were found to contain substantial concentrations of Cu (894.4 ± 267.9 µg g−1) and Fe (998.4 ± 454.0 µg g−1). Significant differences in transfer factors of metals occurred between mushroom species (F11,66 = 5.36, P < 0.001). The most efficient were L. kabansus (for Zn and Ni), A. miomboensis (for Cu and Fe) and T. clypeatus (for Mn, Pb and Co). These species were also among the most preferred mushrooms for consumption based on the interviews conducted. Although 60% of the mushrooms observed were edible, only 20% were frequently consumed during the mushroom season. High positive correlations observed between soils and mushrooms suggest that contamination in mushrooms increases with soil pollution. The estimated daily intake of metals and the target hazard quotient through mushroom consumption were found to be significantly influenced by mushroom species (F11,66 = 38.8, P < 0.001) suggesting that the level of exposure to heavy metals depends on the species of mushroom consumed.

CONCLUSIONS

The study has revealed that heavy metal concentrations in mushrooms exceed permissible limits and vary between species. Transfer efficiency also varies between mushroom species and contamination in mushrooms increases with soil pollution. The fact that concentrations of metals in soil were significantly high, the risk of exposure through mushroom consumption and possibly soil ingestion is even higher. © 2019 Society of Chemical Industry
Application of the Hepatic Transit Time (HTT) in Evaluation of Portal Vein Pressure in Gastroesophageal Varices Patients
Authors: Lin Yuan‐Qiang , Jiang Bo , Li He‐Qun , Jin Chun‐Xiang , Wang Hui
Published: January 2019

Objectives

To analyze the clinical significance of using hepatic transit time (HTT) to evaluate portal vein pressure in gastroesophageal varices patients.

Methods

For the observation group, we enrolled 50 gastroesophageal varices patients who had received esophagogastric variceal embolization in our hospital between January 2015 and February 2018. Patients without liver disease populated the control group and were recruited during the same time period. All patients underwent contrast‐enhanced sonography. In the observation group, free portal pressure (FPP) was detected during esophagogastric variceal embolization with ultrasound guidance. Differences in hepatic artery–hepatic vein transit time (HA‐HVTT), portal vein–hepatic vein transit time (PV‐HVTT), and parenchyma–hepatic vein transit time (PA‐HVTT) were compared between groups. Correlations between HA‐HVTT, PV‐HVTT, PA‐HVTT, and FPP in the observation group were analyzed using the Pearson coefficient and linear regression analysis.

Results

HA‐HVTT (t = 5.078; P < .001), PV‐HVTT (t = 12.163; P < .001), and PA‐HVTT (t = 2.649; P = .009) within the observation group were significantly lower than those of the control group. The areas under the curve of HTT were 0.771 (HA‐HVTT), 0.951 (PV‐HVTT), and 0.652 (PA‐HVTT), and the sensitivity and specificity of PV‐HVTT at 7.99 seconds were 86.0% and 88.0%, respectively. The HA‐HVTT (r = –0.799; P < .001), PV‐HVTT (r = –0.554; P < .001), and PA‐HVTT (r = –0.735; P < .001) negatively correlated to FPP in the observation group. Linear regression analysis showed y = –0.410x + 7.254 (HA‐HVTT and FPP), y = –0.335x + 4.983 (PV‐HVTT and FPP), and y = –0.566x + 4.997 (PA‐HVTT and FPP) in the observation group.

Conclusion

Compared with the control patients, the HTT of patients with portal hypertension–esophagogastric varices was significantly shorter, and showed an inverse relationship with FPP.
Investigation of Radiofrequency Ultrasound‐Based Fibrotic Tissue Strain Imaging Method Employing Endogenous Motion
Authors: Sakalauskas Andrius , Jurkonis Rytis , Gelman Sigita , Lukoševičius Arūnas , Kupčinskas Limas
Published: January 2019

Objectives

The paper presents the results of an initial clinical study, which were obtained using the strain elastography imaging method based on radio frequency ultrasound signal analysis.

Methods

The technique employs endogenous motion of the liver induced by beating heart and vascular pulsatility as an excitation source of tissue microdisplacement. The potential for fibrotic tissue characterization was demonstrated using a clinical data set of radio frequency ultrasound signals (23 healthy controls, 21 subjects with hepatitis, and 16 subjects with liver cirrhosis). Parametric maps, which represent the tissue strain, were derived from the gradient of the integrated spectral coefficient parameter, and correlations with the stage of liver disease were evaluated. Average endogenous strain derived from the gradient of the integrated spectral coefficient parameter and variability (standard deviation) of the strain were evaluated in the rectangular regions of interest (sizes, 1 × 1 and 2 × 2 cm) defined by the observer. The assessment of strain was performed in different frequency subbands of endogenous motion (0–10 Hz and 10–20 Hz).

Results

The best distinction between the groups was observed for the average strain derived from the gradient of the integrated spectral coefficient parameter: the controls, 13.30 ± 6.62; hepatitis, 7.12 ± 7.45; cirrhosis, 3.95 ± 2.44 μm/cm (region of interest, 1 × 1 cm; frequency subband 0–10 Hz), and 10.48 ± 6.02, 8.27 ± 5.41, 3.89 ± 2.07 μm/cm, respectively (2 × 2 cm, 0–10 Hz).

Conclusion

The investigated strain parameters showed statistically significant differences (P < .001) for the different stages of liver fibrosis in most of the cases and proved this method to be feasible.
To tell or not to tell? The roles of perceived norms and self‐consciousness in understanding consumers' willingness to recommend online secondhand apparel shopping
Authors: Lo Carolyn J. , Tsarenko Yelena , Tojib Dewi
Published: January 2019

Secondhand apparel shopping resides in a domain characterized by used goods traditionally associated with financially marginalized consumers. Acknowledging the elusive psychological barriers associated with preowned apparel, this study explores mechanisms that facilitate consumers' willingness to recommend online secondhand apparel shopping. Results from three experimental studies and a cross‐sectional survey of online secondhand shoppers in the United States reveal that hedonic and ethical benefits influence recommendation behavior via perceived norms, whereas economic benefit directly influences consumers' willingness to recommend. Moderated mediation analyses further demonstrate that self‐consciousness alters the strength of the indirect effects, such that consumers with lower self‐consciousness displayed greater willingness to recommend compared to highly self‐conscious consumers. Findings contribute to a greater theoretical understanding of the roles perceived norms and self‐consciousness play in facilitating or inhibiting recommendation behavior in a context that implicitly involves self‐disclosure of one's secondhand purchase behavior. Managerial implications offer insights on salient benefits that can be leveraged to influence word‐of‐mouth recommendation.
An efficient numerical approach to solve Schrödinger equations with space fractional derivative
Authors: Zhang Jun , Lin Shimin , Wang JinRong
Published: January 2019

We design and analyze an efficient numerical approach to solve the coupled Schrödinger equations with space‐fractional derivative. The numerical scheme is based on leap‐frog in time direction and Fourier method in spatial direction. The advantage of the numerical scheme is that only a linear equation needs to be solved for each time step size, and we proved that the energy and mass of space‐fractional coupled Schrödinger equations (SFCSEs) are conserved in the case of full‐discrete scheme. Moreover, we also analyze the error estimate of the numerical scheme, and numerical solutions converge with the order
in L2 norm. Numerical examples are illustrated to verify the theoretical results.
Compact wideband bowtie dipole orthomode transducer
Authors: Fan Jin , Zhu Kai , Yang Jian , Yan Yihua
Published: January 2019

A compact wideband orthomode transducer (OMT) with an octave bandwidth is proposed for a 0.56‐1.12 GHz receiver system in the five hundred meter aperture spherical radio telescope. The OMT operates in a cryostat at a temperature of 70 K and therefore it is critical to minimize its dimension while insuring good electrical properties. The complete OMT comprises 2 bowtie dipoles orthogonally arranged in a circular waveguide. Because of the innovative structure, competing modes, TM01 TE21, and TE01, have been effectively suppressed, and the bandwidth of the dominate mode TE11 has achieved to 2.08:1. The final optimized OMT has a length of 300 mm, shorter than a half of the popular quardruple‐ridged waveguide OMT. Measurements at room temperature agree well with simulation results, with a reflection coefficient below −10 dB for both polarizations and cross‐coupling levels of −30.5 dB over the whole required frequency range.
Log file‐based dose reconstruction and accumulation for 4D adaptive pencil beam scanned proton therapy in a clinical treatment planning system: Implementation and proof‐of‐concept
Authors: Meijers A. , Jakobi A. , Stützer K. , Guterres Marmitt G. , Both S. , Langendijk J. A. , Richter C. , Knopf A.
Published: January 2019

Background and purpose

Motion‐induced uncertainties hamper the clinical implementation of pencil beam scanning proton therapy (PBS‐PT). Prospective pretreatment evaluations only provide multiscenario predictions without giving a clear conclusion for the actual treatment. Therefore, in this proof‐of‐concept study we present a methodology for a fraction‐wise retrospective four‐dimensional (4D) dose reconstruction and accumulation aiming at the evaluation of treatment quality during and after treatment.

Material and methods

We implemented an easy‐to‐use, script‐based 4D dose assessment of PBS‐PT for patients with moving tumors in a commercially available treatment planning system. This 4D dose accumulation uses treatment delivery log files and breathing pattern records of each fraction as well as weekly repeated 4D‐CT scans acquired during the treatment course. The approach was validated experimentally and was executed for an exemplary dataset of a lung cancer patient.

Results

The script‐based 4D dose reconstruction and accumulation was implemented successfully, requiring minimal user input and a reasonable processing time (around 10 min for a fraction dose assessment). An experimental validation using a dynamic CIRS thorax phantom confirmed the precision of the 4D dose reconstruction methodology. In a proof‐of‐concept study, the accumulation of 33 reconstructed fraction doses showed a linear increase of D98 values. Projected treatment course D98 values revealed a CTV underdosage after fraction 25. This loss of target coverage was confirmed in a dose volume histogram comparison of the nominal, the projected (after 16 fractions) and the accumulated (after 33 fractions) dose distribution.

Conclusions

The presented method allows for the assessment of the conformity between planned and delivered dose as the treatment course progresses. The implemented approach considers the influence of changing patient anatomy and variations in the breathing pattern. This facilitates treatment quality evaluation and supports decisions regarding plan adaptation. In a next step, this approach will be applied to a larger patient cohort to investigate its capability as 4D quality control and decision support tool for treatment adaptation.
Isogeometric stability analysis of thin shells: From simple geometries to engineering models
Authors: Guo Y. , Do H. , Ruess M.
Published: January 2019

The buckling properties of thin‐walled structures are sensitive to different sources of imperfections, among which the geometric imperfections are of paramount importance. This work contributes to the methodology of shell buckling analysis with respect to the following aspects: first, we propose an isogeometric analysis framework for the buckling analysis of shell structures which naturally eliminates the geometric discretization errors; second, we introduce a parameter‐free Nitsche‐type formulation for thin shells at large deformations that weakly enforces coupling constraints along trimmed boundaries. In combination with the finite cell method, the proposed conceptual modeling and analysis framework is able to handle engineering‐related shell structures; and third, we introduce a NURBS modeling of measured geometric imperfection fields, which is much closer to the true imperfection shape compared to the classically used faceted FE models. We demonstrate with a number of benchmark problems and engineering models that our proposed framework is able to fully compete with established and highly sophisticated finite element formulations but at a significant higher level of accuracy and reliability of the analysis results.