bluuebunny/crossref_metadata_2025 huggingface dataset:
On the direct and inverse transmission eigenvalue problems for the Schrödinger operator on the half line
Authors: Xu Xiao‐Chuan
Published: May 2020

For the direct problem, we give the asymptotic distribution of the (real and nonreal) transmission eigenvalues for the Schrödinger operator on the half line. For the inverse problem, we prove that the potential can be uniquely determined by all transmission eigenvalues, the parameter in the boundary condition, and some nonzero value related to the potential (whereas without the certain constant γ). The reconstruction algorithms are also revealed.
A high isolation dual‐polarized microstrip patch antenna based on backed substrate integrated cavity and pins‐loaded cross slot
Authors: Wang Jing , Wang Wei , Liu Aimeng , Guo Meng , Wei Zhenyu
Published: May 2020

A X‐band aperture‐coupled patch antenna based on backed substrate integrated cavity (SIC) and pins‐loaded cross slot with dual linear polarization and high isolation is investigated. Loaded pins are applied to cross aperture to reduce the mutual coupling between the slots. SIC is used to reduce the coupling caused by parallel plate mode. Moreover, one‐cross‐point structure of feed networks is used to further improve the isolation. A prototype of the dual‐polarized antenna is fabricated and measured. The measured results show that the dual‐polarized antenna exhibits impedance bandwidths better than 30% (voltage standing wave ratio ≤2), cross polarizations better than −27 dB. And the isolation between the two ports is above 51 dB. To the best knowledge of the authors, this is the highest isolation yet achieved for a patch antenna with wide bandwidth.
Probabilistic analysis of three‐dimensional tunnel face stability in soft rock masses using Hoek–Brown failure criterion
Authors: Zhang Jiahua , Zhang Lianyang , Wang Weijun , Zhang Daobing , Zhang Biao
Published: May 2020

This paper investigates tunnel face stability in soft rock masses via coupled limit and reliability analyses. Specifically, a 3D face collapse mechanism was first constructed. Then the Hoek–Brown failure criterion was introduced into the limit analysis via the tangential technique. Taking the variability of rock mass parameters and loads into consideration, a reliability model was established. The collapse pressure and failure range of tunnel faces were determined. In addition, the required factor of safety (FS) and supporting pressure under three safety levels were obtained, and the corresponding safety level graphs for support design were presented. Comparison of the obtained results with previous work demonstrates the rationality of the 3D collapse mechanism and the validity of the results. A decrease in the geological strength index, Hoek–Brown parameter mi, and uniaxial compressive strength or an increase in the disturbance factor results in a nonlinear increase of the collapse pressure and an enlargement of the failure zone. Such changes also lead to a nonlinear increase of the required support pressure under a certain safety level. By contrast, the FS does not exhibit any obvious change when these parameters vary. Therefore, when a rock mass is of poor quality or heavily disturbed, the advance support should be enlarged from upper front to right above the tunnel face. Moreover, as the safety level increases, both the required FS and supporting pressure of the tunnel face increase nonlinearly at a higher rate.
Fracture closure modes during flowback from hydraulic fractures
Authors: Dahi Taleghani Arash , Cai Yuzhe , Pouya Amade
Published: May 2020

Flowback analysis recently has been considered as a potential tool for assessing induced fractures through corresponding pressure analyses and rate transient analysis. In this paper, we study fracture closure mechanisms during the flowback of fracturing fluid after hydraulic fracturing treatments. Although it is known that flowback can be significantly affected by the geometry of the fractures and closure stress, there has not been any effort to understand the problem from the geomechanical point of view; rather, available studies assume that a fracture closes uniformly with constant fracture compressibility. The coupled geomechanics and fluid flow model presented in this paper help to elucidate how geostresses may affect fracturing fluid recovery under different conditions. We perform a scaling analysis to formulate the occurrence of different fracture closure modes and then use numerical analyses to verify our scaling parameters. The factors governing the flowback process include the mechanical and petrophysical properties of the rock as well as preexisting discontinuities such as natural fractures. Three different closure modes for fracture networks are described and numerically verified. The occurrence of each mode can dramatically affect fracturing fluid recovery. The role of fluid leakoff into the formation, fractures conductivity, and drawdown strategy are examined for each fracture closure scenario.
A Secondary Data Analysis Examining Young Adults’ Performance in an Internet Weight Loss Program with Financial Incentives
Authors: LaRose Jessica Gokee , Leahey Tricia M. , Lanoye Autumn , Reading Jean , Wing Rena R.
Published: May 2020

Objective

In traditional behavioral weight loss (BWL) programs, young adults fare worse than older adults with respect to engagement, retention, and weight loss, but money and use of technology have been cited as program factors that might improve outcomes for this population. This study evaluated young adult performance in internet‐based BWL (IBWL) offering financial incentives for self‐monitoring and weight loss.

Methods

Participants (N = 180; BMI = 33.2 ± 6.0 kg/m2) were randomly assigned to a 12‐week IBWL or IBWL + incentives (IBWL + $) group. This secondary data analysis compared young adults (ages 18‐35) in IBWL (n = 16) with young adults in IBWL + $ (n = 12) on percent weight loss, engagement, and retention. Young adults (n = 28) were also compared with older adults (ages 36‐70; n = 152) on these outcomes.

Results

Young adult weight loss was −2.8% ± 5.2% in IBWL and −5.4% ± 5.7% in IBWL + $ (P = 0.23, partial η2 = 0.06). A greater proportion of young adults in IBWL + $ achieved a 10% weight loss compared with IBWL (42% vs. 6%, P = 0.02). Compared with older adults, young adults were less engaged, but there were no differences for retention or weight loss (P values > 0.05).

Conclusions

Findings suggest that technology‐based BWL has the potential to eliminate weight loss disparities observed between young adults and older adults in in‐person BWL trials. Moreover, adding financial incentives holds promise for promoting clinically meaningful weight loss for young adults.
Should the Same Safety Scrutiny of Antiobesity Medications be Applied to Other Chronic Usage Drugs?
Authors: Halpern Bruno , Mancini Marcio C.
Published: May 2020

Obesity treatment is highly stigmatized, mainly because of the stigma of obesity itself. The frequent withdrawal of medications, lorcaserin being the last example, contributes to this stigma, but it is also probably a reflection of it, as data suggest that the threshold for a withdrawal is lower than with other classes of drugs. Safety should always be an absolute priority for every new medication, especially when used on a chronic basis; however, the safety scrutiny given to antiobesity medications is not given for other medications, such as postmenopausal hormone therapy and central nervous system drugs for psychiatric use. The withdrawal of medications for obesity can also impact future research in the area, so we need transparency and equality. Transparency in knowing exactly what reason led to a drug being discontinued and equality in long‐term safety should be a concern with any medication prescribed for chronic diseases.
Effectiveness of a parent‐targeted video on neonatal pain management: Nonrandomized pragmatic trial
Authors: Korki de Candido Ligyana , Harrison Denise , Ramallo Veríssimo Maria de La Ó , Bueno Mariana
Published: May 2020

The “Be sweet to babies” video is a knowledge translation tool targeted at parents on the use of analgesic strategies during painful procedures performed in neonates. This study aimed to evaluate the effectiveness of the Portuguese version of this video on maternal involvement in neonatal pain management during the newborn screening blood test. Nonrandomized, pragmatic clinical trial. The study was conducted in a rooming‐in unit. All mothers received a pamphlet regarding neonatal pain management and were invited to participate in daily education sessions conducted by nurses, which included the video. The intervention group included mothers who voluntarily watched the video, while the control group was comprised of mothers who did not attend the education sessions or left the session before watching the video. Data were collected by interviews conducted by the research team. Descriptive and inferential analysis considered a confidence interval of 95%. A total of 73 mothers were included in the study. Analgesic strategies were used in 14 (40%) of the procedures in the intervention group and 9 (24%) in the control group, a clinically important difference of 16% points between groups, although no statistically significant difference was found (P = .13). Breastfeeding was the most commonly used strategy. Watching the video increased the chance of implementing analgesic strategies by 2.1 times (P = .19), while nurses suggesting the use of analgesia increased this chance by 5.5 times (P = .006). Although no statistical significance was found, the results suggest the clinical significance and feasibility of the “Be sweet to babies” video as a KT tool targeted at parents on neonatal pain management during nonurgent painful procedures. In addition, maternal involvement in pain care significantly increased when pain relief strategies were recommended by nurses, which suggests that nurses have a key role in facilitating parental participation.
Nano‐in‐Micro Sildenafil Dry Powder Formulations for the Treatment of Pulmonary Arterial Hypertension Disorders: The Synergic Effect of POxylated Polyurea Dendrimers, PLGA, and Cholesterol
Authors: Restani Rita B. , Pires Rita F. , Baptista Pedro V. , Fernandes Alexandra R. , Casimiro Teresa , Bonifácio Vasco D. B. , Aguiar‐Ricardo Ana
Published: May 2020

POXylated polyurea dendrimer nanoparticles (PUREG4OOx48) are loaded with sildenafil (SDF) by a supercritical carbon dioxide–assisted (scCO2) impregnation. Further supercritical CO2‐assisted spray drying (SASD) leads to hybrid nano‐in‐micro dry powder formulations that are investigated aiming at efficient pulmonary delivery of SDF in pulmonary arterial hypertension treatment. This is the first report of the production of poly(D,L‐lactide‐co‐glycolide)‐cholesterol (PLGA‐Chol) microparticles processed by SASD. The optimized formulation of nano‐in‐microparticles is composed of PLGA, Chol, and PUREG4OOx48, loaded with SDF solutions in a 77:23 ratio (PLGA‐Chol:dendrimer, w/w). The dry powders are fully characterized and found to be highly biodegradable and biocompatible, and the SDF release profile evaluates under different pH values. The median mass average diameter (MMAD) of the nano‐in‐micro systems varies between 2.57 and 5 µm and the fine particle fraction (FPF) between 36% and 29% for PUREG4OMeOx48[PLGA‐Chol] and PUREG4OEtOx48[PLGA‐Chol], respectively. The data validate the potential use of these new formulations in inhalation therapy. In vitro studies are also carried out in order to evaluate the effect of the free drug in cell viability and formulations cytotoxicity.
Preparation and Characterization of Aluminum‐Lithium Alloy Powder Coated by In‐situ Polymerization of Styrene
Authors: Cao Zhengyu , Hu Aobo , Xia Bin , Pang Ai‐min , Cai Shuizhou
Published: May 2020

Aluminum‐lithium alloy powder has broad application prospects in the field of energetic materials due to its good thermal performance. However, the high reactivity of lithium and the incompactness of the surface oxide layer result in the continuous oxidation of the active metal during storage, thereby deteriorating the thermal performance of the powder. In this paper, a layer of polystyrene (PS) was successfully coated on the surface of Al‐10Li (10 wt.%) alloy powder by in‐situ polymerization of styrene (St). According to an orthogonal test, the optimum coating conditions for protection factor were as follows: m(St)/m(Al‐10Li) was 1 : 1; m(AIBN)/m(St) was 5 %; the reaction temperature was 75 °C; the reaction time was 4 h. The structure, surface morphology and thermal properties were characterized by XPS, FTIR, SEM and TG‐DTA. Furthermore, the aging stability of powders were studied by TG‐DTA. The results showed that the decay rate of the weight increase of the active metal of Al‐10Li alloy powder decreased significantly after coating, which demonstrated that the polystyrene coating effectively protected the active metal of Al‐10Li alloy powder, prevented pre‐oxidation of Al‐10Li alloy powder in air and improved its storage stability.
The next generation of venom‐based drugs
Authors: Greener Mark
Published: May 2020

Some venom‐derived drugs, such as captopril and exenatide, are already used therapeutically, and researchers are continuing to develop new venom‐based treatments for a wide range of conditions, including autoimmune and cardiovascular diseases, chronic pain and cancer. This article explores the potential for new venom‐based drugs and some of the problems researchers need to overcome.
Conductivity Modulation of a Slit Channel in a Monolayer MoS2 Homostructure
Authors: Kong Xiangcong , Li Tao , Xu Yeming , Cao Lin , Lu Minghui , Wu Di , Min Tai
Published: May 2020

The 1D‐edge structure can potentially demonstrate higher conductivity in 2D materials because of dangling bonds and symmetry breaking. Studies use edge contact to circumvent the contact‐scaling problem in 2D field‐effect transistors (FETs) but with a rather complicated device fabrication process. Herein, a new concept is proposed directly using edges as the modulated channel, realized in a simple monolayer MoS2 homostructure. When two 1D edges lie close to each other, they form a slit, which may demonstrate distinctive electronic features. The local conductivity along naturally and artificially created slits in monolayer MoS2 is evaluated using noninvasive scanning microwave impedance microscopy with high spatial resolution. It is found that the two edges of the slits can show dramatically different conductivity due to the potential difference between the two parts separated by the slit, which can be controlled independently by the back‐gate voltage and scanning conditions. Even when the back‐gate voltage is off, the potential difference across the slit can retain, which makes it nonvolatile. This feature enables a MoS2 flake to work as a homostructure device, in which the slit can perform as an efficient channel. The findings provide an alternative perspective of using slit as a new approach for 2D electronic devices.
The effect of green tea supplementation on obesity: A systematic review and dose–response meta‐analysis of randomized controlled trials
Authors: Lin Ying , Shi Dianfeng , Su Bo , Wei Jing , Găman Mihnea‐Alexandru , Sedanur Macit Melahat , Borges do Nascimento Israel Júnior , Guimaraes Nathalia Sernizon
Published: May 2020

The effects of green tea (GT) in obese subjects have been evaluated in different studies, but no consensus has been obtained due to the heterogeneity of the results. The dosage, the type of extract, and the duration of the intervention are the main contributors to the heterogeneity of the results. Therefore, the present systematic review and meta‐analysis aimed to evaluate the efficacy and dose–response relationship of GT. Several databases were searched from inception to September 2019 to identify clinical trials that examined the influence of GT supplements on obesity indices in humans. Combined results using the random‐effects model indicated that body weight (WMD: −1.78 kg, 95% CI: −2.80, −0.75, p = .001) and body mass index (BMI) (WMD: −0.65 kg/m2, 95% CI: −1.04, −0.25, p = .001) did change significantly following GT administration. The reduction in waist circumference (WC) after GT consumption was significant in subjects in trials employing GT ≥800 mg/day (WMD: −2.06 cm) and with a treatment duration <12 weeks (WMD: −2.39 cm). Following the dose–response evaluation, GT intake did alter body weight, with a more important reduction when the GT dosage was <500 mg/day and the treatment duration was of 12 weeks. The results of present meta‐analysis study support the use of GT for the improvement of obesity indices. Thus, we suggest that the use of GT can be combined with a balanced and healthy diet and regular physical exercise in the management of obese patients.
Association of cardiovascular events with antidepressants in the elderly
Authors: Lam Y. W. Francis
Published: May 2020

Many patients with cardiovascular disease exhibit depressive symptoms and are treated with antidepressants. The literature has long suggested concerns regarding adverse effects of tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) on the heart, including risk of arrhythmias. A recent study examined the relationship between antidepressants and adverse cardiovascular events in elderly patients with a history of cardiovascular disease.
Calculation of core‐level electron spectra of ionic liquids
Authors: Lembinen Meeri , Nõmmiste Ergo , Ers Heigo , Docampo‐Álvarez Borja , Kruusma Jaanus , Lust Enn , Ivaništšev Vladislav B.
Published: May 2020

On the example of 40 ion pairs (5 cations times 8 anions), this study demonstrates how the core‐level binding energy values can be calculated and used to plot theoretical spectra at low computational cost using density functional theory methods. Three approaches for obtaining the binding energy values are based on delta Kohn–Sham (ΔKS) calculations, 1s KS orbital energies, and atomic charges. The ΔKS results show reasonable agreement with the available experimental X‐ray photoelectron data. The 1s KS orbital energies correlate well with the ΔKS results. Atomic charge correlation with ΔKS is improved by accounting for the charges of neighboring atoms. Assignment of binding energies to atoms and the applicability of the mentioned methods to model systems of ionic liquids are discussed.
Autoimmune pulmonary alveolar proteinosis prior to myelodysplastic syndrome
Authors: Foo Chuan Tai , Chhor Louis , Thien Francis
Published: May 2020

We report the first case of autoimmune pulmonary alveolar proteinosis (PAP) associated with and preceding myelodysplastic syndrome. A 74‐year‐old female with a history of polymyalgia rheumatica presented with six months history of progressive exertional breathlessness. Examination revealed bilateral chest crackles and exertional desaturation. A diagnosis of autoimmune PAP was made based on the presence of autoantibodies to granulocyte‐macrophage colony‐stimulating factor and characteristic findings on chest computed tomography, bronchoalveolar lavage, and transbronchial biopsies. Bilateral whole lung lavage was performed with prompt improvement in symptoms. Fourteen months later, she presented with new breathlessness and was diagnosed with myelodysplasia on bone marrow biopsy. No recurrence of alveolar proteinosis was detected. This case highlights the importance of follow‐up and screening of patients with autoimmune PAP for haematological conditions.
Parameterized bilinear matrix inequality techniques for gain‐scheduling proportional integral derivative control design
Authors: Shi Ye , Tuan Hoang Duong , Apkarian Pierre
Published: May 2020

Proportional‐integral‐derivative (PID) structured controller is the most popular class of industrial control but still could not be appropriately exploited in gain‐scheduling control systems. To gain the practicability and tractability of gain‐scheduling control systems, this paper addresses thegain‐scheduling PID control. The design of such a controller is based on parameterized bilinear matrix inequalities, which are then solved via a bilinear matrix inequality optimization problem of nonconvex optimization. Several computational procedures are developed for its computation. The merit of the developed algorithms is shown through the benchmark examples.
On the adaptive control of robot manipulators with velocity observers
Authors: Arteaga–Pérez Marco A. , Ortiz–Espinoza Alethia , Romero José G. , Espinosa–Pérez Gerardo
Published: May 2020

To achieve accurate tracking control of robot manipulators many schemes have been proposed. A common approach is based on adaptive control techniques, which guarantee trajectory tracking under the assumption that the robot model structure is perfectly known and linear in the unknown parameters, while joint velocities are available. Despite tracking errors tend to zero, parameter errors do not unless some persistent excitation condition is fulfilled. There are few works dealing with velocity observation in conjunction with adaptive laws. In this note, an adaptive control/observer scheme is proposed for tracking position of robot manipulators. It is shown that tracking and observation errors are ultimately bounded, with the characteristic that when a persistent excitation condition is matched then they, as well as the parameter errors, tend to zero. Simulation results are in good agreement with the developed theory.
Characterizing the pore size distribution of a chloride silt soil during freeze–thaw processes via nuclear magnetic resonance relaxometry
Authors: Liu Jianpeng , Yang Ping , Li Lin , Zhang Ting
Published: May 2020

Soil pore size distribution (PSD) is typically used to predict the soil freezing characteristic curve and estimate the hydrological and mechanical properties during freeze–thaw cycles. However, direct measurements of frozen soil PSD remain a great challenge. This study proposed a method to determine the PSD of frozen soils based on nuclear magnetic resonance (NMR) relaxometry. Tests were performed on a saturated chloride silt soil at different salt contents (0.3, 1.0, 2.0, and 3.0%) and temperatures (between –30 and 0 °C) during a freeze–thaw cycle. The NMR‐detected PSD (only accounting for pores occupied by unfrozen water) varied with soil temperature, salt content, and freeze–thaw cycle. The sequence of the water–ice phase change and hysteresis were also identified in a freeze–thaw cycle. A regression analysis was performed on the cumulative NMR‐detected PSD via a variant van Genuchten model. The critical freezing pore radius and the thickness of unfrozen water film were computed and used to transform NMR‐detected PSD into the actual PSD of frozen soils on the basis of a pore radius transformation equation established in this paper. Notably, the actual PSD accounted for pores occupied by ice and unfrozen water. The actual PSD indicated that the water–ice phase change was more pronounced in macro‐ and mesopores, especially at lower temperatures and salt content. A comparison between the calculated average pore size and those presented in other studies showed that the proposed technique is a valuable alternative for the prediction of actual frozen soil PSD.
Self‐Phosphorization of MOF‐Armored Microbes for Advanced Energy Storage
Authors: Hu Jiapeng , Yuan Xietao , Wang Chonglong , Shao Xixi , Yang Baiyu , Abdul Razzaq Amir , Zhao Xiaohui , Lian Yuebin , Deng Zhao , Chen Muzi , Peng Yang
Published: May 2020

Utilization of microbes as the carbon source and structural template to fabricate porous carbon has incentivized great interests owing to their diverse micromorphology and intricate intracellular structure, apart from the obvious benefit of “turning waste into wealth.” Challenges remain to preserve the biological structure through the harsh and laborious post‐synthetic treatments, and tailor the functionality as desired. Herein, Escherichia coli is directly coated with metal–organic frameworks (MOFs) through in situ assembly to fabricate N, P co‐doped porous carbon capsules expressing self‐phosphorized metal phosphides. While the MOF coating serves as an armoring layer for facilitating the morphology inheritance from the bio‐templates and provides metal sources for generating extra porosity and electrochemically active sites, the P‐rich phospholipids and N‐rich proteins from the plasma membrane enable carbon matrix doping and further yield metal phosphides. These unique structural and compositional features endow the carbon capsules with great capabilities in suppressing polysulfide shuttling and catalyzing reversible oxygen conversion, ultimately leading to the superb performance of lithium–sulfur batteries and zinc–air batteries. Combining the bio‐templating strategy with hierarchical MOF assembly, this work opens a new avenue for the fabrication of highly porous and functional carbon for advanced energy applications.
Thermoplasmonic‐Triggered Release of Loads from DNA‐Modified Hydrogel Microcapsules Functionalized with Au Nanoparticles or Au Nanorods
Authors: Wang Chen , Vázquez‐González Margarita , Fadeev Michael , Sohn Yang Sung , Nechushtai Rachel , Willner Itamar
Published: May 2020

Microcapsules consisting of hydrogel shells cross‐linked by glucosamine–boronate ester complexes and duplex nucleic acids, loaded with dyes or drugs and functionalized with Au nanoparticles (Au NPs) or Au nanorods (Au NRs), are developed. Irradiation of Au NPs or Au NRs results in the thermoplasmonic heating of the microcapsules, and the dissociation of the nucleic acid cross‐linkers. The separation of duplex nucleic acid cross‐linkers leads to low‐stiffness hydrogel shells, allowing the release of loads. Switching off the light‐induced plasmonic heating results in the regeneration of stiff hydrogel shells protecting the microcapsules, leading to the blockage of release processes. The thermoplasmonic release of tetramethylrhodamine‐dextran, Texas Red‐dextran, doxorubicin‐dextran (DOX‐D), or camptothecin‐carboxymethylcellulose (CPT‐CMC) from the microcapsules is introduced. By loading the microcapsules with two different drugs (DOX‐D and CPT‐CMC), the light‐controlled dose release is demonstrated. Cellular experiments show efficient permeation of Au NPs/DOX‐D or Au NRs/DOX‐D microcapsules into MDA‐MB‐231 cancer cells and inefficient uptake by MCF‐10A epithelial breast cells. Cytotoxicity experiments reveal selective thermoplasmon‐induced cytotoxicity of the microcapsules toward MDA‐MB‐231 cancer cells as compared to MCF‐10A cells. Also, selective cytotoxicity towards MDA‐MB‐231 cancer cells upon irradiation of the Au NPs‐ and Au NRs‐functionalized microcapsules at λ = 532 or 910 nm is demonstrated.
Barriers to contrast‐enhanced ultrasound in New Zealand and proposed solutions
Authors: Necas Martin , Ong Qi Hao
Published: May 2020

Introduction

Contrast‐enhanced ultrasound (CEUS) appears underutilised in New Zealand (NZ). The purpose of this survey was to gain an understanding of the barriers that prevent NZ practitioners from implementing CEUS and to offer practical solutions on how to solve such barriers.

Methods

A questionnaire was distributed to 88 delegates of two regional meetings on the topic of CEUS convened in Tauranga and Auckland, NZ in November and December 2019.

Results

Response rate was 82%. Of the 72 respondents, 56 were sonographers and 14 radiologists. The 72 respondents provided 129 responses regarding the barriers that have hindered them or their department in implementing and performing CEUS. The most common barriers were lack of knowledge on part of sonographers or radiologists (n = 23, 42%), lack of support from radiologists (n = 21, 38%), uncertainty about funding or charges (n = 14, 25%), lack of interest on part of radiologists (7, 12%) and lack of leadership (7, 12%).

Conclusion

This study revealed a broad range of barriers that have prevented practitioners of ultrasound from implementing and performing CEUS. The analysis of these barriers and practical solutions are provided so that readers who are not yet performing CEUS can anticipate and address these common barriers.
Numeric modelling of innovative semi‐rigid connections under cyclic loading
Authors: Aydin Abdulkadir Cüneyt , Ardalani Aysan , Maali Mahyar , Kiliç Mahmut
Published: May 2020

This paper presents the analytical results of six steel bolted T‐connection models and four steel bolted beam‐to‐column connection models with top and seat angles. This study was undertaken to analyse the influence of bolted T‐connections instead of welded connections and the influence of angles with and without stiffeners on the behaviour of the beam‐to‐column connections under hysteretic loading. The aim was to compare the energy dissipation of different connections with each other. The energy dissipation characteristics are obtained from the main characteristics of moment‐rotation hysteresis curves. This study shows that the energy dissipation decreased by about 2–29 % and 2–13 % for bolted T‐connection and top‐and‐seat‐angle connection models respectively after switching from one cycle to another in five hysteretic loadings.
Influence of nano SiO2 and nano CaCO3 particles on strength, workability, and microstructural properties of fly ash‐based geopolymer
Authors: Durak Uğur , Karahan Okan , Uzal Burak , İlkentapar Serhan , Atiş Cengiz Duran
Published: May 2020

The influence of nano SiO2(NS) and CaCO3(NC) particles on the properties of class F fly ash based geopolymer mortar activated with different sodium ion concentrations have been investigated. Mortar mixture proportions were 1:3:0.3 for binder, sand, and water, respectively. Nano SiO2 and CaCO3 particles were replaced with a binder by weight basis at the ratios of 1, 2, and 3% in the mixtures. Sodium concentrations amount used were 8, 10, and 12% Na+ of binder content. Geopolymer mortar samples were cured at 60, 75, and 90°C in a furnace for 24, 48, and 72 hr. After the heat curing process, flexural, and compressive strength tests were performed. The changes in the microstructure of geopolymer due to influence of nanoparticles were examined by utilizing isothermal calorimetric studies on geopolymer paste, and field‐emission scanning electron microscopy (FESEM). Based on laboratory work results, it was concluded that for all sodium ion concentrations, the addition of nano SiO2 and CaCO3 particles improved the flexural and compressive strengths after 24 hr heat curing. However, the favorable effects of nanoparticles on strength properties tend to disappear after 48 and 72 hr heat curing. The results of isothermal calorimetric studies showed that nano SiO2 and CaCO3 particles accelerated the geopolymeric reactions at an early age. FESEM results showed that additions of nanoparticles made the microstructure of geopolymer products more intense and compact.
Synthesis, Characterization, Structural Description, Micellization Behavior, DNA Binding Study and Antioxidant Activity of 4, 5 and 6‐Coordinated Copper(II) and Zinc(II) Complexes
Authors: Iqbal Muhammad , Karim Amir , Ali Saqib , Bilal Hazrat , Rehman Ata Ur
Published: May 2020

Four mononuclear copper(II) and zinc(II) complexes were synthesized by the reaction of copper and zinc salts with 3,4‐dichlorophenylactic acid, 2‐bromophenylactic acid, biphenylacetic acid (O‐donor ligand) and bipyridine (N‐donor ligands) having the general formulae [(L)2Cu(bp)(H2O)] (1), [(BpA)2Cu(bp)] (2), [(L)2Zn(bp)(H2O)] (3) and [(L*)2Zn(bp)] (4) (L = 3,4‐dichlorophenylacetate, L* = 2‐bromophenylacetate bp = bipyridine, and BpA = biphenylacetate). Structures of all compounds were characterized through FT‐IR spectroscopy and X‐ray diffraction analysis. FT‐IR spectra of all complexes confirmed the binding mode of Cu‐O and Zn‐O. XRD data revealed that complexes 1–3 exhibited distorted octahedral arrangement, whereas complex 4 has a distorted tetrahedral environment. Micellization behavior was examined with anionic surfactant (SDS) by conductance measurement as well as absorption spectral analysis. DNA binding study was assessed through viscosity measurement and UV/Vis spectrophotometry. DPPH free radical scavenging assay was measured by UV/Vis spectrophotometry. The results showed nice biological potential of all the complexes.
Interspinifex Ni sulfide ore from Victor South-McLeay, Kambalda, Western Australia
Authors: Staude Sebastian , Barnes Stephen J. , Markl Gregor
Published: May 2020

Spinifex-textured olivine plates hosted in sulfides are usually named “interspinifex ore” in komatiite-hosted sulfide deposits. This ore type is rare but provides important genetic information on sulfide deposits, komatiite volcanology and thermomechanical erosion processes. Occurrences in Victor South-McLeay and Moran South (Kambalda, Western Australia) differ significantly from previously reported occurrences in their stratigraphic location, position within the ore profile and textural appearance. Thus, their formation process has to be reconsidered. Interspinifex ore reported here is situated in the lower portion of the basal lava flow between massive and net-textured sulfides in the centre of the embayment and between massive sulfides and older basalt in a “pinchout” where the sulfides melted sideways into older basalt on the embayment edge. Interspinifex ore is composed of up to 10-cm-long aggregates of parallel plates in the upper portion of massive sulfides and is overlain by barren komatiite. The texture does not allow for a classic single explanation. Thus, two possible formation mechanisms are envisaged: (1) A younger komatiite melt intrudes into its own olivine and sulfide liquid cumulate pile, while the sulfides are still liquid. The injection on top of the sulfides causes the formation of an emulsion, from which the spinifex forms due to the temperature gradient between the melts. (2) Interspinifex ore is a relic of an early komatiite flow formed in a series of successive pulses of komatiite and sulfide liquid. The spinifex of the komatiite is invaded by a younger batch of sulfide liquid replacing interstitial silicate melt.
All congruences below stability-preserving fair testing or CFFD
Authors: Valmari Antti
Published: May 2020

In process algebras, a congruence is an equivalence that remains valid when any subsystem is replaced by an equivalent one. Whether or not an equivalence is a congruence depends on the set of operators used in building systems from subsystems. Numerous congruences have been found, differing from each other in fine details, major ideas, or both, and none of them is good for all situations. The world of congruences seems thus chaotic, which is unpleasant, because the notion of congruence is at the heart of process algebras. This study continues attempts to clarify the big picture by proving that in certain sub-areas, there are no other congruences than those that are already known or found in the study. First, the region below stability-preserving fair testing equivalence is surveyed using an exceptionally small set of operators. The region contains few congruences, which is in sharp contrast with an earlier result on the region below Chaos-Free Failures Divergences (CFFD) equivalence, which contains 40 well-known and not well-known congruences. Second, steps are taken towards a general theory of dealing with initial stability, which is a small but popular detail. This theory is applied to the region below CFFD.
Acute Care Surgery Models Worldwide: A Systematic Review
Authors: van der Wee Mats J. L. , van der Wilden Gwendolyn , Hoencamp Rigo
Published: May 2020

Background

The Acute Care Surgery (ACS) model was developed as a dedicated service for the provision of 24/7 nontrauma emergency surgical care. This systematic review investigated which components are essential in an ACS model and the state of implementation of ACS models worldwide.

Methods

A literature search was conducted using PubMed, MEDLINE, EMBASE, Cochrane library, and Web of Science databases. All relevant data of ACS models were extracted from included articles.

Results

The search identified 62 articles describing ACS models in 13 countries. The majority consist of a dedicated nontrauma emergency surgical service, with daytime on‐site attending coverage (cleared from elective duties), and 24/7 in‐house resident coverage. Emergency department coverage and operating room access varied widely. Critical care is fully embedded in the original US model as part of the acute care chain (ACC), but is still a separate unit in most other countries. While in most European countries, ACS is not a recognized specialty yet, there is a tendency toward more structured acute care.

Conclusions

Large national and international heterogeneity exists in the structure and components of the ACS model. Critical care is still a separate component in most systems, although it is an essential part of the ACC to provide the best pre‐, intra‐ and postoperative care of the physiologically deranged patient. Universal acceptance of one global ACS model seems challenging; however, a global consensus on essential components would benefit any healthcare system.
Measuring NO and temperature in plasma preheated air using UV absorption spectroscopy
Authors: Sepman Alexey , Gullberg Marcus , Wiinikka Henrik
Published: May 2020

A new fast sensor for simultaneous high temperature diagnostics (above 800 K) of nitrogen oxide (NO) concentration and gas temperature (T) was developed based on the spectral fitting of low-resolution NO UV absorption near 226 nm. The sensor was intended for process control in future low-carbon footprint heavy process industries using renewable powered electro fuels (e.g. H2, NH3) or plasma torches as heat source. Due to excitation of molecular vibration, the shape of the selected NO feature, including (0, 0), (1, 1), and (2, 2) vibrational transitions of the A2Σ+ − X2Π2 electronic system had a strong temperature sensitivity at temperatures above 800 K. The fitting was made using the well-known NO molecular constants of the A2Σ+ − X2Π2 electronic system. To reduce the computational time, a library of the molecular spectra calculated at different temperatures was created. The fitting of an experimental spectrum representing the convolution of the instrument line function of the spectrometer with the molecular spectra was performed using the pre-calculated library spectra. Based on comparison with conventional measurement methods, the accuracy of the developed sensor was within 15% for NO and about 40 K for T, clearly showing the potential for fast in situ diagnostics in hot process gases.
Linking fluid dynamics and olivine crystal scale zoning during simulated magma intrusion
Authors: Cheng Lilu , Costa Fidel , Bergantz George
Published: May 2020

The compositional zoning styles of natural crystals produced during magma intrusion can be used to investigate the structure of magmatic plumbing systems and its relation to expressions of volcanic unrest (seismic, deformation, volatiles). However, magma intrusion is a progressive, dynamic process and yields non-monotonic heterogeneities in physio-chemical variables such as complex spatial variations in temperature and liquid composition with time. Such changes in variables are difficult to incorporate in models of crystal zoning in natural systems. Here we take another approach by integrating the results of a numerical multiphase simulation of melt arrival in an olivine-rich reservoir with models of chemical re-equilibration of olivine. We evaluate the diversity of chemical zoning styles and the inferred time scales using Fe–Mg diffusion in olivine for a limited range of system geometries and time-composition-temperature values. Although our models are still a large simplification of the processes that may occur in natural systems we find several time-dependent and systematic relations between variables that can be used to better interpret natural data. The proportions of zoned and unzoned crystals, the zoning length scales, and the calculated diffusion times from the crystals, vary with time and the initial position of the crystal in the reservoir. These relationships can be used, for example, to better constrain the plumbing structure and dynamics of mafic eruptions from monogenetic volcanoes by detailed studies of changes in the zoning of the crystal cargo with eruptive sequence. Moreover, we also find that the time scales obtained from modeling of crystals at a single temperature and boundary condition tend to be shorter (> about 25%) than the residence time, which could also be tested in natural studies by combining crystal time scale records with monitoring datasets.
Theoretical study on preference of open polymer vs. cyclic products in CO2/epoxide copolymerization with cobalt(III)-salen bifunctional catalysts
Authors: Roznowska Aleksandra , Dyduch Karol , Lee Bun Yeoul , Michalak Artur
Published: May 2020

The preference of open chain of growing macromolecule vs. possible cyclic form was examined for the bifunctional cobalt(III)-salen catalyst for the copolymerization of CO2 with epoxides. A variety of possible isomers was considered (resulting from trans/cis-β salen arrangement, different mutual orientation of quaternary ammonium-chains, and possible binding modes). To explore the conformational space, a combined approach was applied, utilizing semiempirical (PM7) MD and the DFT calculations. The preference of the open and cyclic macromolecules attached to the metal center was compared with the corresponding results for isolated model macromolecules, and the systems built of the macromolecule interacting with the tetra-butyl ammonium cation. Result shows that the cyclic structures are strongly preferred for isolated ions, with relatively low cyclization barriers. In the field of positive point charge, the open structures are strongly preferred. For the ions interacting with tetrabutyl ammonium cation, the cyclic structures are preferred, due to delocalization of the positive charge in the cation. For the complexes involving model and “real” Co(III)-salen catalysts, the open structures are strongly preferred. The possible cyclization by dissociation of alkoxide and its transfer to the neighborhood of quaternary ammonium cation is characterized by high activation barriers. Further, the transfer of alkoxide from the metal center to the cation is less likely than the transfer of carbonate, since the metal-alkoxide bond-energy energy is much stronger than energy of metal-carbonate bonding, as shown by ETS-NOCV results. The conclusions are in qualitative agreement with experimental data showing high selectivity towards copolymer formation in the copolymerization processes catalyzed by bifunctional Co(III) salen-complexes.
Granular dampers in microgravity: sharp transition between modes of operation
Authors: Sack Achim , Windows-Yule Kit , Heckel Michael , Werner Dominik , Pöschel Thorsten
Published: May 2020

When a container filled with granular material is subjected to sinusoidal vibration in microgravity, dependent on the amplitude of the oscillation, the granulate may exhibit one of two distinct dynamical modes: at low amplitude, a gas-like state is observed, where the particles are relatively homogeneously distributed within the container, almost independent of the phase of the oscillation. In contrast, for large amplitude, collective motion of the particles is favoured, termed collect-and-collide regime. Both regimes are characterized by very different dissipation characteristics. A recent model predicts that the regimes are separated by a sharp transition due to a critical amplitude of the vibration. Here we confirm this prediction of a sharp transition and also the numerical value of the critical amplitude by means of experiments performed under conditions of weightlessness.
Polygenic risk scores indicates genetic overlap between peripheral pain syndromes and chronic postsurgical pain
Authors: van Reij Roel R. I. , Voncken Jan Willem , Joosten Elbert A. J. , van den Hoogen Nynke J.
Published: May 2020

Chronic postsurgical pain (CPSP) is a debilitating chronic pain condition that has a substantial effect on quality of life. CPSP shows considerable clinical overlap with different chronic peripheral pain syndromes, suggesting a shared aetiology. This study aims to assess the genetic overlap between different chronic pain syndromes and CPSP, providing relevant biological context for potential chronic pain markers of CPSP. To analyse the genetic overlap between CPSP and chronic peripheral pain syndromes, recent GWAS studies were combined for polygenic risk scores (PRS) analysis, using a cohort of CPSP patients as starting point. Biological contextualisation of genetic marker, overlap between CPSP and chronic pain syndromes, was assessed through Gene Ontology (GO), using Pathway Scoring Algorithm (PASCAL) and REVIGO. PRS analyses suggest a significant genetic overlap between CPSP and 3 chronic pain disorders: chronic widespread pain (CWP, p value threshold = 0.003, R2 0.06, p = 0.003), rheumatoid arthritis (RA, p value threshold = 0.0177, R2 = 0.04, p = 0.017) and possibly sciatica (p value threshold = 0.00025, R2 = 0.03, p = 0.045). Whereas no significant genetic overlap was found with cluster headache and migraine, the outcome for osteoarthritis (OA) was inconsistent between the cohorts. This is likely related to cohort composition, as repeated random reallocation of patients’ nullified CPSP/OA outcome variation between the discovery and replication cohorts. GO analyses suggested an aetiological involvement of genetic markers that control neurological signalling (specifically sodium channels) and inflammatory response. The current study reaffirms the impact of sample size, cohort composition and open data accessibility on the unbiased identification of genetic overlap across disorders. In conclusion, this study is the first to report genetic overlap between regulatory processes implicated in CPSP and chronic peripheral pain syndromes. Interaction between neurological signalling and inflammatory response may explain the genetic overlap between CPSP, CWP and RA. Enhanced understanding of mechanisms underlying chronification of pain will aid the development of new therapeutic strategies for CPSP with sodium channel biochemistry as a potential candidate.
Fully inkjet-printed glucose assay fabricated on highly porous pigment coating
Authors: Jutila Eveliina , Koivunen Risto , Bollström Roger , Gane Patrick
Published: May 2020

A simple paper-based microfluidic device, fabricated on a highly porous coating consisting of functionalised calcium carbonate (FCC) pigment and a microfibrillated cellulose (MFC) and/or polyvinyl alcohol (PVOH) binder, was developed for glucose detection. Both the hydrophobic patterns, consisting of alkyl ketene dimer (AKD), and the enzyme ink, consisting of glucose oxidase (GOx), horseradish peroxidase (HRP) and an indicator containing 4-aminoantipyrine (4-AAP), and sodium 3,5-dichloro-2-hydroxy-benzenesulphonic acid (DHBS) were inkjet-printed. Multiple coating formulations were tested using two indicators, potassium iodide (KI) and 4-AAP/DHBS, to find the optimal formulation with regard to detection sensitivity and assay stability. Higher binder concentrations increased the enzyme activity, especially in the case of PVOH. Two coatings, containing either solely MFC or both MFC and PVOH were ultimately chosen for the glucose assay experiments. For the assays, a 42 nl volume of buffered enzyme solution, containing a total of 5.04 mU GOx and approximately 1.01 mU HRP, in combination with 4 mM 4-AAP and 8 mM DHBS, was printed, and a 1 µl glucose solution, made up over a range of concentrations, was applied onto the samples to evaluate the response. A good linearity was achieved between detection and glucose concentration between 0.1 and 0.6 mM with both coatings. The assays remained stable for four weeks when stored at − 20 °C. The results show that the functional coated substrates offer a viable alternative to cellulose-based substrates for microfluidic applications enabling the use of small reagent and sample volumes.