bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of curing conditions on long term mechanical property of improved surplus soils
Authors: Miyashita Yukika , Sanjeewani Dayani , Kuwano Reiko
Published: June 2019

In this study, the effect of environmental exposure conditions on the long term mechanical property of surplus soils improved by lime and cement was investigated by conducting unconfined compression tests on the specimens cured under different conditions. As the result of the experiments after about 1 year (336 days) from specimen preparation, the unconfined compressive strengths of the soaked specimens were found to be the smallest, while those of the sealed specimens were the largest. Effect of soaking on the strengths appeared obviously in the cement treated soil, while the effect decreased when the duration of initial sealed curing increased. It was inferred that these differences in the strengths were caused by the changes in physical properties such as degree of saturation, and chemical properties due possibly to the leaching of hydration products during soaked curing.
Multi-scale analysis on soil improved by alkali activated binders
Authors: Vitale Enza , Russo Giacomo , Deneele Dimitri
Published: June 2019

In the present paper, the use of alkali activated binders to improve engineering properties of clayey soils is presented as an alternative to traditional binders such as lime or cement. An alkali-activated fly ash and its chemo-physical evolution has been monitored at increasing curing times by means of X-Ray Diffraction and Scanning Electron Microscopy. Alkali-activated binder has been mixed with soil for evaluating the improvement of its mechanical behaviour. One-dimensional compression tests on treated samples have been performed with particular reference to effects induced by binder content and curing time. Test results showed a high initial reactivity of the alkali activated systems promoting formation of new mineralogical phases responsible of the mechanical improvement of the treated soil.
Small Strain Stiffness of Artificially Cemented Soft Clay: Modelling the Effect of Structure Degradation
Authors: Khan Qasim , Ng Yannick , Ku Taeseo
Published: June 2019

This paper presents a study on the evolution of small strain stiffness (Gmax) along vertical and horizontal directions for lightly cemented clay. Soft clays have historically been a subject for studying the evolution of stiffness anisotropy under varying loading conditions. These studies have focused on stress history (overconsolidation) effects as well. However, for lightly cemented clays, such studies are limited and their main scope has primarily been on the evolution of vertically aligned stiffness (GVH) at varying effective confining stresses. This study investigates the effect of isotropic loading on uncemented and lightly cemented kaolin clay. Kaolin clay mixed with 10% cement is used in this study. Stiffness measurements have been conducted using bender elements for obtaining GVH and GHH hence resulting in the measurement of vertical and horizontal stiffness values respectively. By comparing the behaviour of both samples, the influence of bonding and fabric due to cementation on the evolution of stiffness and anisotropy is studied. In order to characterize the behavior of structure in cemented soil with confining stress, a modelling equation is applied for the cemented sample to predict the variation of Gmax before and after yielding.
Geotechnical characteristics of polystyrene treated sand
Authors: Yoon Boyeong , Kim Jang-un , Lee Jihwan , Lee Woojin
Published: June 2019

Many polymeric materials are recently used in geotechnical practice for enhancing the engineering properties of soils. Among the various polymers, this study aims at investigating the geotechnical properties of silica sand coated with polystyrene(PS), which is rarely studied in geotechnical engineering. The polystyrene coated sand was prepared by polymerizing styrene monomer on the surface of silanized sand with median diameter of 0.467 mm. Testing specimens were prepared at 3 different initial relative densities (30, 50 and 70%) by air pluviation. Comprehensive experiments, including one-dimensional compression test with bender elements and triaxial test, were performed to observe the change in geotechnical properties due to the coating of PS on sand surface. The results demonstrate that the adsorbed polymer plays different roles according to strain levels. At very small strain, the polymer on the sand surface may increase the interparticle contact area by applying additional adhesion force between soil particles, leading to an increase in Gmax. However, with an increase in strain level, the polymer will act as the lubricant between sand particles; therefore, the coated sand can show increased compression index and decreased friction angle.
Experimental analysis of the effect of electrokinetic treatment of soils
Authors: Gargano Sara , Lirer Stefania , Liguori Barbara , Flora Alessandro
Published: June 2019

In Europe, large amounts of materials are dredged annually to maintain channels and harbour activities. Consolidation processes in dredged sediments take very long-time due to the high-water content, much more than those considered in the typical problems of geotechnical engineering. The electrokinetic treatment (EK) can be an effective technique to accelerate the dewatering of these sediments and, at the same time, to improve their mechanical properties. An experimental research is under course at the University of Napoli Federico II with the aim to analyse the effects induced by EK treatments on the physic-chemical and mechanical properties of two different soils. Some laboratory tests have been carried out in a special apparatus (special oedometer) adopting two different pore fluids (tap water and sea water). The laboratory results show that the effect of EK treatment, both in terms of induced water flow and improvement of soil mechanical properties, is affected by the chemical properties of the pore fluid and by the physical and mineralogical characteristics of the particles. The results obtained at the macro-scale (specimen) have been analysed at the micro-scale by means of X-ray diffraction analysis and Scanning Electron Microscopy, comparing the microstructures of treated and untreated soils specimens.
Mechanical Behaviour of Reinforced Sand with Natural Curauá Fibers through Full Scale Direct Shear Tests
Authors: Coelho de Carvalho Leila Maria , Dal Toé Casagrande Michelé
Published: June 2019

Inclusion of natural fibers (sisal, curauá, coco fiber and others) for soil improvement has been the study object in diverse geotechnical areas and it is a topic of growing interest, within the research area of new geotechnical materials. The state of the art in this subject highlights excellent results as soil strength parameters improve and post-cracking strength (toughness) increase. Soil reinforcement technique with fibers is established in the technology of composite materials, this being a combination of two or more materials presenting properties that the component materials do not possess on their own. The aim of this paper is to study the mechanical behaviour of sand-fiber composite by inserting natural curauá fibers into a sandy matrix, with different fiber contents. The fibers were randomly distributed in the soil mass. The experimental program included physical and mechanical characterization of the composites, using full-scale direct shear tests, with samples measuring 30 x 30 cm and 15 cm high. Direct shear tests were carried out using fibers with 25 mm length and 0.5 and 0.75% fiber content (relative to the soil dry weight). The specimens also presented a relative density of 50% and moisture content of 10%. It was sought to establish a pattern behaviour so that the addition of curauá fiber influence can be explained, thus, comparing with the sandy soil shear strength parameters. Inclusion of natural curauá fibers as soil reinforcement presented satisfactory results, as an increase in the soil shear strength parameters was observed when compared with sandy soil results.
Vane shear strength of bio-improved sand reinforced with natural fibre
Authors: Usman Qureshi Mohsin , Al-Hilly Abdulsalam , Al-Zeidi Ola , Al-Barrami Ashwaq , Al-Jabri Ahed
Published: June 2019

In the recent developments, bio-improvement has considerably enhanced the geotechnical properties and reduced degradation of loose desert sand without the environmental concerns. However, the effect of bio-improvement on sand weakens due to water submergence. Therefore, it is necessary to explore the techniques for retaining the strength of bio-improved sand in water submerged state. So, this paper reports the geotechnical performance of submerged bio-improved sand reinforced by discrete natural fibres. The desert sand sampled from Al-Sharqia Desert of Oman, bio-improved by xanthan gum and reinforced by discrete natural fibres obtained from date palm tree. Date palm fibres having a diameter less than 0.2mm and length 1cm were employed for sand reinforcement. Vane shear tests and standard compaction tests were performed on specimens having different mix ratios of sand-xanthan gum with and without natural fibres. The qualitative description of bio-improvement and fibre reinforcement effect on the desert sand is also presented as the photomicrographs taken by field emission scanning electron microscope. According to the results of strength tests at higher moisture content state, the discrete fibre reinforcement has enhanced the geotechnical performance of sand improved at lower concentrations.
Evaluation of resilient behavior of a clayey soil with polyethylene terephthalate (PET) insertion for application in pavements base
Authors: Carvalho Bárbara , Casagrande Michéle , Farias Márcio
Published: June 2019

The growing production and consumption of PET bottles represent a major environmental problem because they end up being improperly discarded in nature or simply stocked. With the aim to attenuate the environmental problem caused by this residue, this research proposes the use of PET flakes as an alternative material for pavements base. In order to analyze the geotechnical performance of the material, physical tests, compaction and Cyclic Triaxial tests (Resilient Modulus) were carried out on pure soil as well as on the mixture of soil and PET flakes in weight percentages of 3, 5 and 7 %. The computer program SisPav (Franco, 2007) was used to perform a mechanistic-empirical design for a typical pavement structure with parameters obtained for the mixtures. The results indicated that the insertion of PET influences the mechanical behavior of the soil. It was found that resilient modulus increases, with respect to that of pure soil, for mixtures with the lowest content of PET (3%). For tests with higher contents of PET flakes, the Resilient Modulus decreases. This research concluded that the clayey soil mixed with PET flakes can be used as an alternative material for pavements base, as long as a low content of flakes is used.
Influence of thermal cycles on the deformation of soil-pile interface in energy piles
Authors: Vasilescu Roxana , Yin Kexin , Fauchille Anne-Laure , Kotronis Panagiotis , Dano Christophe , Manirakiza Richard , Gotteland Philippe
Published: June 2019

Energy piles are double purpose foundation elements used both for transferring loads to the soil and temperature regulation in buildings. The response of the pile-soil interface is influenced by daily and seasonal temperature variations. In order to assess the impact of thermal cycles on the mobilization of shear strength in energy piles, a series of saturated soil-concrete interface direct shear tests were performed in the laboratory for different temperature gradients with a new interface direct shear device adapted for thermomechanical loading. As natural soils are very complex due to a high variability of mineralogy and anisotropy, silica and carbonate sands were chosen in this study. Those sands are considered as the main types of sandy soils commonly met in geotechnics. The experimental campaign is divided in two parts: (i) Concrete-soil direct shear tests at 13°C (constant temperature) to be used as a reference (ii) Concrete-soil direct shear tests after 10 temperature cycles with a gradient ΔT=10°C, under submerged conditions. For these two types of soils, realistic temperature cycles applied between 8 and 18°C cause the overall low contraction of the samples. However the interface friction angles are not significantly modified before and after the temperature cycles. Even if the vertical strains of soils are cumulative along temperature cycles, soil’s strains and friction angle changes are relatively negligible for the temperatures and water content tested, which support the low impact of temperature cycles on the deformation of soil concrete foundation under submerged conditions. These experimental results bring new features which will be implemented in numerical models to study the long-term use of energy piles.
Effect of Interface Friction on Passive Force on Bridge Abutments
Authors: Rollins Kyle , Fredrickson Amy , Scott Eric
Published: June 2019

A correct understanding of passive force-deflection response is important for lateral load evaluations of bridges during extreme events such as earthquakes and from thermal expansion and contraction of the superstructure. In these cases, the ultimate passive force is highly sensitive to the interface friction between the abutment wall and the adjacent geomaterials. These geomaterials may simply consist of compacted sand or gravel; however, for geosynthetic reinforced soil (GRS) backfill a geosynthetic fabric may be placed between the abutment wall and soil which can reduce the interface friction. In still other cases, a zone of compressible material such as geofoam may be used as a barrier between the soil and abutment to reduce lateral earth pressures. To evaluate the effect of the interface friction on passive force-deflection curves, large-scale testing was performed with a test abutment that was 3.35 m wide and 1.68 m high. Backfill materials consisted of sand, gravel, GRS backfill, and a geofoam inclusion between a sand backfill and the abutment. As a result of lower interface friction, the GRS backfills only developed 80% of the force developed by the unreinforced gravel. The geofoam inclusion decreased the passive force by about 70% as a result of reduced interface friction.
Three-dimensional numerical assessment of axial and torsional interface shear behaviour
Authors: Su Jiaxing , Frost David , Martínez Alejandro
Published: June 2019

Interfaces between geo-materials and soils play a critical role in a wide spectrum of geotechnical structures and soil/site characterization techniques in geotechnical engineering. Consequently, understanding the mechanics of interface shear behaviour at different scales can benefit both soil characterization and the design of geotechnical systems. This paper presents a series of numerical simulations that utilize the 3D discrete element modelling (DEM) technique and compares the results with those obtained from laboratory counterpart tests under axial and torsional axisymmetric interface shear. The difference observed in macro- and meso-scale responses under these loading conditions, such as shear strength, volumetric change, and shear zone characteristics are evaluated. In addition, responses at microscale including particle displacement trajectory, particles rotation, and local void ratio evolution are assessed allowing for links to the results obtained at larger spatial scales. These 3D numerical model studies expand the micromechanical processes under different shearing conditions previously presented by the authors from 2D to 3D space.
Modelling of undrained shearing of soft natural clays
Authors: Petalas Alexandros L. , Karlsson Mats , Karstunen Minna
Published: June 2019

stress-strain response of soft natural clays is characterised by anisotropy, destructuration and rate-dependency. An accurate constitutive description of these materials should take into consideration all of the characteristics above. In this paper, two constitutive models for soft soils, namely the SCLAY1S and Creep-SCLAY1S models are used to simulate the undrained response of two soft natural clays, Gothenburg clay from Sweden and Otaniemi clay from Finland. The SCLAY1S model accounts for the effect of inherent and induced anisotropy and destructuration, while the Creep-SCLAY1S accounts also for the creep and rate effects. The model simulations are compared against triaxial compression and extension tests on anisotropically consolidated samples. The results demonstrate the need to incorporate all features represented in the Creep-SCLAY1S model when modelling structured natural clays.
Preliminary assessment of variability of selected Hardening Soil model parameters for glacial tills and clays from Poland
Authors: Bogusz Witold , Witowski Marcin
Published: June 2019

Typical ranges of variability of basic soil parameters are relatively well known. Such knowledge is important to aid engineers in the selection of characteristic values for design or as a basis for conducting sensitivity analyses for more complex soil-structure interaction problems. However, for application of advanced non-linear constitutive models, which often are defined by model-specific parameters, such variability is rarely known. To improve parameter estimation, as well as to provide a basis for the choice of realistic variability range, a database of high quality laboratory tests can be used. The paper presents the results of preliminary assessment of variability of selected Hardening Soils model parameters for overconsolidated glacial tills and clays from Poland, based on a local database of triaxial test results.
Stress-strain behaviour of Toyoura sand in undrained triaxial compression
Authors: Dołżyk-Szypcio Katarzyna
Published: June 2019

The stress-plastic dilatancy relationship for Toyoura sand sheared under undrained triaxial conditions was analysed by use of Frictional State Theory. Under undrained conditions, plastic strain increments are counterbalanced by elastic strain increments. The linear stress ratio-plastic dilatancy relationships at different stages of sand shear were obtained by assuming that Poisson's ratio is a function of shear strain. Contrary to a drained condition, natural state parameter values are not special for characteristic points of sand behaviour under undrained conditions.
Recent centrifuge modelling of offshore geotechnical problems at IWHR
Authors: Liang Jianhui , Song Xianhui
Published: June 2019

Centrifuge modelling has been proven to be an efficient and reliable approach for examining offshore geotechnical problems. This study reports the two series of centrifuge tests to understand the behaviour of spudcan penetration in a “soft-stiff-soft clay” stratigraphy and the behaviour of gravity anchor subjected to a lateral loading. A hydraulic system has been adopted to apply the large compressive and tensional load on the spudcan and gravity anchor, respectively. Load cells were installed on the base of the spudcan to directly measure the stress acting on the spudcan base. A 2D laser scanner was adopted to monitor the horizontal, vertical movement and tilting of the gravity anchor. The influence of the relative soil stiffness on the spudcan pentration behaviour and the soil deformation and interaction with the gravity anchor are discussed based on the centrifuge test results.
Examining the seismic behaviour of partially saturated sand using centrifuge shaking table tests
Authors: Zhang Zitao , Xiao Jianzhang , Wei Yingqi , Cai Hong , Liang Jianhui , Yan Jun
Published: June 2019

Similar to fully saturated sand, the partially saturated sand can also liquefy under certain conditions during earthquakes. This study aims to characterize the seismic behaviour of partially saturated sand. Centrifuge shaking table tests were performed using the IWHR horizontal-vertical centrifuge shaker. The experimental results indicate that the liquefaction resistance of the partially saturated sand increases with decreasing the degree of saturation and with increasing the initial effective stress right before shaking. The boundary between the liquefied and un-liquefied sand becomes deeper and deeper during shaking.
Rainfall induced erosion of soils used in earth roads
Authors: Ngezahayo Esdras , Burrow Michael P.N. , Ghataora Gurmel S.
Published: June 2019

Earth roads in rural areas of the developing world are key engines to the development of countries. They give access to education and health services, sustain agriculture and businesses, and promote social interactions between communities. However, earth roads suffer substantially from poor engineering and funding for construction and maintenance. Rainfall is probably their most dangerous enemy resulting in soil particle detachment leading to the loss of surface material. A laboratory rainfall simulator was used to identify the performance of an earth road surface compacted at the maximum dry density against rainfall energy and surface flow. Under the rain intensity of 30mm/hr, erosion increased with rain duration from 0 to 30 minutes. Fine sand (0.06 – 0.02mm) and medium sand (0.02 – 0.6mm) particles eroded faster than coarse sand (0.6 – 2mm) and gravel (> 2mm) particles of the sediments collected at 5 minutes intervals of time. Additionally, a 20cm x 20cm photograph at the same place was analysed using ImageJ software and showed reduction in number of particles from 18554 at 10 min to 5803 at 25 min as smaller particles had eroded in the meantime.
A proposed method to determine in-situ shear modulus and shear strain decay curves in different structured soil
Authors: An Ran , Kong Lingwei , Guo Aiguo , Zhang Xianwei
Published: June 2019

This paper illustrates the application of the self-boring pressuremeter test and the seismic dilatometer test to acquire the in-situ decay curves of stiffness with shear strain level (G-γ decay curves) of three types of structural soil, which are granite residual soil, structural soft soil and expansive soft rock. The proposed approach in combines the functions of SBPT and SDMT to provide the high standard of accuracy for the small-strain stiffness (from SDMT) and the major attenuation stage of stiffness (from SBPT). Using the proposed mathematical model can properly describe the tendency in typical in-situ G-γ decay curves based on the data of tests. To analyse the suitability of the proposed approach, the G-γ curve obtain from the resonant column test of granite residual soil is also employed to compare with the in-situ curves. The shear modulus G obtained from laboratory tests is found to be smaller and the stiffness attenuation rate is found to be faster than the curve of the in-situ test, which reflects the process of sampling, transporting and preparation of soil samples could cause unrecoverable damages in soil.
Internal Mammary Lymph Node Visualization as a Sentinel Sonographic Sign of Tuberculous Pleurisy
Authors: Messineo Ludovico , Quadri Federico , Valsecchi Alberto , Lonni Sara , Palmiotti Antonio , Giampietro Marchetti
Published: June 2019

Background Tuberculous pleurisy is one of the primary sites of extrapulmonary tuberculosis, but clinicians currently lack the diagnostic tools necessary for early recognition in the absence of typical signs and symptoms. With this study, we aimed to test the association between internal mammary adenopathies and tuberculous pleurisy (TP).

Methods 60 patients with a post-thoracoscopic histological diagnosis of granulomatosis or acute infective pleurisy were retrospectively enrolled. All of them had chest sonography and/or CT scan data available. At least two expert chest sonography physicians re-analyzed the sonography images to look for any internal mammary adenopathy. Such findings were compared to the CT data.

Results Chest sonography showed internal mammary adenopathy ipsilateral to the pleural effusion in 97 % of 29 patients who had a diagnosis of TP, and in 13 % of those with an acute infective pleurisy (p < 0.001). Receiver operator characteristic analysis revealed 97 % sensitivity and 87 % specificity for this technique in predicting TP (area under curve 0.92 ± 0.04, p < 0.001). CT detection power and node measures were significantly similar (p < 0.001).

Conclusion Sonographic internal mammary node visualization ipsilateral to the pleural effusion may become a sentinel sign for TP, contributing to early diagnosis or orienting the diagnostic management towards invasive procedures in uncertain cases.
Ultrasound-Guided High Intensity Focused Ultrasound Ablation for Symptomatic Uterine Fibroids: Preliminary Clinical Experience
Authors: Lyon Paul Christopher , Rai Vic , Price Natalia , Shah Aarti , Wu Feng , Cranston David
Published: June 2019

Objective To evaluate the middle-term efficacy and complications of ultrasound-guided high intensity focused ultrasound (USgHIFU) for the treatment of symptomatic uterine fibroids in an NHS population.

Methods A prospective observational single-center study at a single university hospital in Oxford, UK. Patients with symptomatic uterine fibroids who declined standard surgical/radiological intervention and were referred to the HIFU unit were considered for USgHIFU treatment. Clinical evaluation, adverse event monitoring, uterine fibroid symptoms and health-related quality of life questionnaire (UFS-QOL) and contrast-enhanced pelvic magnetic resonance imaging (MRI) were performed before and at regular intervals after treatment to assess patient outcome.

Results 12 of 22 referred patients underwent one session of USgHIFU ablation of 14 fibroids overall and received a two-year follow-up. No serious adverse events were reported, but a second-degree skin burn was observed in one patient who had a surgical scar from a previous caesarean section. Mean symptom severity scores (SSS-QOL) improved significantly from 56.5 ± 29.1 (SD) at baseline to 33.4 ± 23.3 (p < 0.01) at three months, 45.0 ± 35.4 (p < 0.05) at one year and 40.6 ± 32.7 (p < 0.01) at two years post-treatment. The mean non-perfused volume ratio was 67.7 ± 39.0 % (SD) in the treated fibroids (n = 14) within three months of treatment. The mean volume reduction rates of the treated fibroids were 23.3 ± 25.5 % (SD) at 3 months post-treatment (p < 0.01, n = 14), 49.3 ± 23.7 % at 12 months (p < 0.05, n = 8), and 51.9 ± 11.1 % at 24 months (p < 0.005, n = 8).

Conclusion This study demonstrates the clinical efficacy of USgHIFU ablation of uterine fibroids and the low risk of complications. We believe that this noninvasive approach may offer an alternative therapy for women with symptomatic uterine fibroids. While HIFU is fast becoming the standard of care for fibroid ablation in other countries, to our knowledge, this study is the first to present clinical experience of US-guided HIFU ablation of symptomatic uterine fibroids in an NHS population.

Plain Language Summary High intensity focused ultrasound (HIFU) can be used for the noninvasive ablation of symptomatic uterine fibroids, and MR-guided treatment has already gained FDA approval. Ultrasound-guided HIFU has the advantage of offering practicalities in anesthesia and considerable cost-savings over MR-guided treatments. In this prospective study we have demonstrated the middle-term efficacy and favorable safety profile of ultrasound-guided HIFU for the treatment of symptomatic uterine fibroids for the first time in an NHS population.
Molecular Targets Involved in the Neuroprotection Mediated by Terpenoids
Authors: González-Cofrade Laura , de las Heras Beatriz , Apaza Ticona Luis , Palomino Olga M.
Published: June 2019

Natural products and their derivatives represent the most consistently successful source of drug leads. Terpenoids, a structurally diverse group, are secondary metabolites widely distributed in nature, endowed with a wide range of biological activities such as antibacterial, anti-inflammatory, antitumoral, or neuroprotective effects, which consolidate their therapeutic value. During the last decades, and taking into consideration the prevalence of aging-related diseases, research activity into the neuroprotective effects of these types of compounds has increased enormously. Several signaling pathways involved in neuroprotection are targets of their mechanism of action and mediate their pleiotropic protective activity in neuronal cell damage. In the present review, molecular basis of the neuroprotection exerted by terpenoids is presented, focusing on preclinical evidence of the therapeutic potential of diterpenoids and triterpenoids on neurodegenerative disorders. By acting on diverse mechanisms simultaneously, terpenoids have been emphasized as promising multitarget agents.
First Stereoselective Total Synthesis of Ciryneol C
Authors: Sharada Ambati , Kundeti Lakshmi Srinivasa Rao , Ramakrishna Kallaganti V. S. , Nagaiah Kommu
Published: June 2019

The acetylene derivative Ciryneol C was isolated from the roots of C. japonicum. The asymmetric total synthesis of Ciryneol C was achieved in seven steps, with Horner–Wittig olefination, regioselective epoxide opening, and Cadiot–Chodkiewicz coupling reactions being the key steps.
Click Chemistry Approach to Isoindole-1,3-dione Tethered 1,2,3-Triazole Derivatives
Authors: Kaur Rajneesh , Singh Raman , Kumar Antresh , Singh Kuldeep
Published: June 2019

A convenient and efficient approach for the synthesis of novel 1,2,3-triazole tethered isoindol-1,3-dione conjugates by a nucleophilic substitution reaction of phthalic anhydride with 1,2,3-triazole containing carbohydrazide is described. The latter were prepared by using click chemistry.
Theoretical studies of silicon hetero-junction solar cells with rib structure
Authors: Ichikawa Yukimi , Osawa Yoshiaki , Noge Hiroshi , Konagai Makoto
Published: June 2019

The open-circuit voltage of a solar cell is known to increase with deceasing wafer thickness if the cell is adequately passivated. However, it is not easy to handle very thin wafers because they are brittle and are subject to warpage. To provide thinned wafers that have adequate mechanical strength, we proposed a thin Si wafer-based solar cell that uses a rib structure in a previous work. We formed a lattice-shaped rib structure on the rear side of a thin Si wafer to improve the wafer’s strength and fabricated the conventional Si hetero-junction structure by depositing hydrogenated amorphous Si on the wafer. For optimum design of the rib structure cell, we analytically studied the effect of rib dimensions on wafer strength and photovoltaic characteristics. A simplified structural analysis was performed to investigate the mechanical strength of the rib structure for various rib dimensions. Photovoltaic characteristics of rib structure silicon hetero-junction cells were also studied by a two-dimensional device simulator to understand the effect of rib dimensions. From these analyses, we theoretically demonstrated that the rib structure cell is a very good candidate to realize thin wafer Si solar cell, and can achieve both mechanical strength and electrical performance of thin Si solar cells.
Open-source software compares Abel transforms for easy use
Authors: Jaycen Amelia
Published: June 2019

PyAbel makes Abel transforms plug-and-play, so users can try them all, compare the results and benefit from a user-friendly interface that enables efficient data-processing.
Resonator responses to coupled vibrational modes lead to regions of unstable oscillation
Authors: Bandari Anashe
Published: June 2019

Researchers studied the dynamic behavior of MEMS resonators in the presence of coupled vibrational modes and used it to build a bifurcation diagram.
On mixed dynamics of two-dimensional reversible diffeomorphisms with symmetric non-transversal heteroclinic cycles
Authors: Gonchenko S. V. , Gonchenko M. S. , Sinitsky I. O.
Published: June 2019

We consider one-parameter families (general unfoldings) of two-dimensional reversible diffeomorphisms that contain a diffeomorphism with a symmetric non-transversal heteroclinic cycle. We show that in such families there exist Newhouse intervals of parameters such that the values corresponding to the co-existence of infinitely many stable, completely unstable, saddle and symmetric elliptic periodic orbits are generic (that is, they form Baire second-category sets). Also, the closures of the sets of orbits of different types have non-empty intersections.
Linear forms of a given Diophantine type and lattice exponents
Authors: German O. N.
Published: June 2019

In this paper we prove an existence theorem concerning linear forms of a given Diophantine type and apply it to study the structure of the spectrum of lattice exponents.
Instantaneous blow-up versus local solubility of the Cauchy problem for a two-dimensional equation of a semiconductor with heating
Authors: Korpusov M. O. , Panin A. A.
Published: June 2019

We consider the Cauchy problem for a model third-order partial differential equation with non-linearity of the form

. We prove that for

the Cauchy problem in

has no local-in-time weak solution for a large class of initial functions, while for

a local weak solution exists.
Recruiting people with HIV to an online self-management support randomised controlled trial: barriers and facilitators
Authors: Klassen Karen M. , Millard Tanya , Stout Julia , McDonald Karalyn , Dodson Sarity , Osborne Richard H. , Battersby Malcolm W. , Fairley Christopher K. , Kidd Michael R. , McMahon James , Baker David , Elliott Julian H.
Published: June 2019

Background
Recruitment of people to randomised trials of online interventions presents particular challenges and opportunities. The aim of this study was to evaluate factors associated with the recruitment of people with HIV (PWHIV) and their doctors to the HealthMap trial, a cluster randomised trial of an online self-management program. Methods: Recruitment involved a three-step process. Study sites were recruited, followed by doctors caring for PWHIV at study sites and finally PWHIV. Data were collected from study sites, doctors and patient participants. Factors associated with site enrolment and patient participant recruitment were investigated using regression models. Results: Thirteen study sites, 63 doctor participants and 728 patient participants were recruited to the study. Doctors having a prior relationship with the study investigators (odds ratio (OR) 13.3; 95% confidence interval (CI) 3.0, 58.7; P = 0.001) was positively associated with becoming a HealthMap site. Most patient participants successfully recruited to HealthMap (80%) had heard about the study from their HIV doctor. Patient enrolment was associated with the number of people with HIV receiving care at the site (β coefficient 0.10; 95% CI 0.04, 0.16; P = 0.004), but not with employing a clinic or research nurse to help recruit patients (β coefficient 55.9; 95% CI –2.55, 114.25; P = 0.06). Conclusion: Despite substantial investment in online promotion, a previous relationship with doctors was important for doctor recruitment, and doctors themselves were the most important source of patient recruitment to the HealthMap trial. Clinic-based recruitment strategies remain a critical component of trial recruitment, despite expanding opportunities to engage with online communities.
dTcf/Pangolinsuppresses growth and tumor formation inDrosophila
Authors: Song Shilin , Andrejeva Diana , Freitas Flávia C. P. , Cohen Stephen M. , Herranz Héctor
Published: June 2019

Wnt/Wingless (Wg) signaling controls many aspects of animal development and is deregulated in different human cancers. The transcription factor dTcf/Pangolin (Pan) is the final effector of the Wg pathway inDrosophilaand has a dual role in regulating the expression of Wg target genes. In the presence of Wg, dTcf/Pan interacts with β-catenin/Armadillo (Arm) and induces the transcription of Wg targets. In absence of Wg, dTcf/Pan partners with the transcriptional corepressor TLE/Groucho (Gro) and inhibits gene expression. Here, we use the wing imaginal disk ofDrosophilaas a model to examine the functions that dTcf/Pan plays in a proliferating epithelium. We report a function of dTcf/Pan in growth control and tumorigenesis. Our results show that dTcf/Pan can limit tissue growth in normal development and suppresses tumorigenesis in the context of oncogene up-regulation. We identify the conserved transcription factorsSox box protein 15(Sox15) andFtz transcription factor 1(Ftz-f1) as genes controlled by dTcf/Pan involved in tumor development. In conclusion, this study reports a role for dTcf/Pan as a repressor of normal and oncogenic growth and identifies the genes inducing tumorigenesis downstream of dTcf/Pan.
Tracking the evolution of CNS remyelinating lesion in mice with neutral red dye
Authors: Baydyuk Maryna , Cha David S. , Hu Jingwen , Yamazaki Reiji , Miller Evan M. , Smith Victoria N. , Kelly Katherine A. , Huang Jeffrey K.
Published: June 2019

Significance

To develop therapeutic strategies that enhance repair processes during central nervous system (CNS) injury, the molecular and cellular changes occurring at the injury site must be determined. However, precisely isolating the injury site, such as lesions in animal models of demyelination, has been difficult. We developed a simple and powerful method to track and analyze changes that occur within the lesion microenvironment over time. We demonstrated that neutral red-labeled lesions could be selectively isolated and processed for detailed analyses of transcripts, proteins, cell populations, and metabolites. The results of our study can be used to identify molecular pathways that promote CNS repair and the development of therapies to modulate neuroinflammation or enhance regeneration in demyelinating disorders such as multiple sclerosis.
Chemical depletion of phagocytic immune cells in
Anopheles gambiae
reveals dual roles of mosquito hemocytes in anti-
Plasmodium
immunity
Authors: Kwon Hyeogsun , Smith Ryan C.
Published: June 2019

Mosquito immunity is composed of both cellular and humoral factors that provide protection from invading pathogens. Immune cells known as hemocytes, have been intricately associated with phagocytosis and innate immune signaling. However, the lack of genetic tools has limited hemocyte study despite their importance in mosquito anti-
Plasmodium
immunity. To address these limitations, we employ the use of a chemical-based treatment to deplete phagocytic immune cells in
Anopheles gambiae,
demonstrating the role of phagocytes in complement recognition and prophenoloxidase production that limit the ookinete and oocyst stages of malaria parasite development, respectively. Through these experiments, we also define specific subtypes of phagocytic immune cells in
An. gambiae
, providing insights beyond the morphological characteristics that traditionally define mosquito hemocyte populations. Together, this study represents a significant advancement in our understanding of the roles of mosquito phagocytes in mosquito vector competence and demonstrates the utility of clodronate liposomes as an important tool in the study of invertebrate immunity.
Sfrp4 repression of the Ror2/Jnk cascade in osteoclasts protects cortical bone from excessive endosteal resorption
Authors: Chen Kun , Ng Pei Ying , Chen Ruiying , Hu Dorothy , Berry Shawn , Baron Roland , Gori Francesca
Published: June 2019

Significance

Cortical bone homeostasis combines periosteal bone formation and endocortical remodeling. Flaws in these processes lead to altered cortical bone mass. Yet, little is known about the regulatory specificities of the endocortical vs. the periosteal surfaces, both critical in determining cortical thickness. We have shown that Pyle’s disease is due to loss-of-function mutations in the Wnt antagonist SFRP4 and that its deletion in mice causes skeletal deformities closely mimicking those seen in Pyle’s disease: cortical bone thinning. Here, we further elucidate the mechanism by which cortical bone is affected and report that both osteoblast- and osteoclast-expressed Sfrp4 regulate osteoclastogenesis and that Sfrp4-dependent suppression of the noncanonical Wnt/Ror2/Jnk cascade in osteoclasts protects cortical bone from excessive endocortical resorption.
Hybridization of singular plasmons via transformation optics
Authors: Yu Sanghyeon , Ammari Habib
Published: June 2019

Significance

Surface plasmons, which are optical resonances supported by metallic nanostructures, are extremely useful for manipulating light on the nanoscale. However, designing novel plasmonic devices becomes quite challenging when the desired spectral response pattern is highly complex. Here we show that, by developing a theoretical model which combines plasmon hybridization theory with transformation optics, one can control both global and local features of the resonance spectrum in an intuitive way. As an application, we design a plasmonic metasurface whose absorption spectrum can be controlled over an extremely large class of complex patterns through only two structural parameters. Our theoretical model paves the way for the next generation of plasmonic devices, allowing for the efficient design of complex systems.
The sRNA DicF integrates oxygen sensing to enhance enterohemorrhagicEscherichia colivirulence via distinctive RNA control mechanisms
Authors: Melson Elizabeth M. , Kendall Melissa M.
Published: June 2019

To establish infection, enteric pathogens integrate environmental cues to navigate the gastrointestinal tract (GIT) and precisely control expression of virulence determinants. During passage through the GIT, pathogens encounter relatively high levels of oxygen in the small intestine before transit to the oxygen-limited environment of the colon. However, how bacterial pathogens sense oxygen availability and coordinate expression of virulence traits is not resolved. Here, we demonstrate that enterohemorrhagicEscherichia coliO157:H7 (EHEC) regulates virulence via the oxygen-responsive small RNA DicF. Under oxygen-limited conditions, DicF enhances global expression of the EHEC type three secretion system, which is a key virulence factor required for host colonization, through the transcriptional activator PchA. Mechanistically, thepchAcoding sequence (CDS) base pairs with the 5′ untranslated region of the mRNA to sequester the ribosome binding site (RBS) and inhibit translation. DicF disruptspchA cis-interactions by binding to thepchACDS, thereby unmasking thepchARBS and promoting PchA expression. These findings uncover a feed-forward regulatory pathway that involves distinctive mechanisms of RNA-based regulation and that provides spatiotemporal control of EHEC virulence.
Noninvasive preimplantation genetic testing for aneuploidy in spent medium may be more reliable than trophectoderm biopsy
Authors: Huang Lei , Bogale Berhan , Tang Yaqiong , Lu Sijia , Xie Xiaoliang Sunney , Racowsky Catherine
Published: June 2019

Significance

In clinical in vitro fertilization (IVF), the prevailing method for preimplantation genetic testing for aneuploidy (PGT-A) requires biopsying a few cells from the trophectoderm (TE), the lineage that forms the placenta. The test is invasive, requires specialized skills, and suffers from false positives and negatives because chromosome numbers in the TE and the inner cell mass (ICM), which develops into the fetus, are not always the same. Noninvasive PGT-A (niPGT-A), which is based on sequencing DNA released into the culture medium from both TE and ICM, may offer a solution to these problems but has previously had limited efficacy. The present results show improved sensitivity and reliability of niPGT-A, suggesting a potentially superior test for noninvasive and cost-effective PGT-A in clinical IVF.
Hydrodynamic changes due to coastal reclamation activities in Daya Bay
Authors: Yin Yi , Jiang Lifang , Zhang Zhixu , Yu Hongbing
Published: June 2019

Based on the geometry and surface in Daya Bay, we artificially divided the reclamation projects into three periods to analyze the influences and changes on hydrodynamic conditions as a result of the reclamation projects. Three periods of tidal current fields, tidal prisms, and water exchange capacity are simulated by the Finite-Volume, primitive equation Community Ocean Model and the characteristics and trends of hydrodynamics in Daya Bay are discussed. The combination of observation and simulation in this paper gives a good description on the tidal dynamic system in Daya Bay. As indicated by model results, the tidal current velocity in the Bay totally decreases after numerous activities associated with reclamation construction. The decreasing current velocity region is mainly distributed near the Xiachong and Gangkou chain islands. The current velocity in 2015 decreases by approximately 5 cm s−1 compared with velocities before 2000. Future reclamation activities will exacerbate these decreasing current velocity trends in some regions. Compared with 2015, the tidal prism has significantly decreased by 1.3622 × 107 m3 due to planned reclamation. The half-water exchange times for Daya Bay in 2015 and after planned reclamation are 178.9 and 177.4 days, respectively. The water exchange capacity in Fanhe Harbor is weaker than other water fields throughout Daya Bay.
A tensile trilayered cytoskeletal endotube drives capillary-like lumenogenesis
Authors: Khan Liakot A. , Jafari Gholamali , Zhang Nan , Membreno Edward , Yan Siyang , Zhang Hongjie , Gobel Verena
Published: June 2019

Unicellular tubes are components of internal organs and capillaries. It is unclear how they meet the architectural challenge to extend a centered intracellular lumen of uniform diameter. In an RNAi-based Caenorhabditis elegans screen, we identified three intermediate filaments (IFs)—IFA-4, IFB-1, and IFC-2—as interactors of the lumenal membrane-actin linker ERM-1 in excretory-canal tubulogenesis. We find that IFs, generally thought to affect morphogenesis indirectly by maintaining tissue integrity, directly promote lumenogenesis in this capillary-like single-cell tube. We show that ERM-1, ACT-5/actin, and TBB-2/tubulin recruit membrane-forming endosomal and flux-promoting canalicular vesicles to the lumen, whereas IFs, themselves recruited to the lumen by ERM-1 and TBB-2, restrain lateral vesicle access. IFs thereby prevent cystogenesis, equilibrate the lumen diameter, and promote lumen forward extension. Genetic and imaging analyses suggest that IFB-1/IFA-4 and IFB-1/IFC-2 polymers form a perilumenal triple IF lattice, sandwiched between actin and helical tubulin. Our findings characterize a novel mechanism of capillary-like lumenogenesis, where a tensile trilayered cytoskeletal endotube transforms concentric into directional growth.
Identification of monocyte-like precursors of granulocytes in cancer as a mechanism for accumulation of PMN-MDSCs
Authors: Mastio Jérôme , Condamine Thomas , Dominguez George , Kossenkov Andrew V. , Donthireddy Laxminarasimha , Veglia Filippo , Lin Cindy , Wang Fang , Fu Shuyu , Zhou Jie , Viatour Patrick , Lavilla-Alonso Sergio , Polo Alexander T. , Tcyganov Evgenii N. , Mulligan Charles , Nam Brian , Bennett Joseph , Masters Gregory , Guarino Michael , Kumar Amit , Nefedova Yulia , Vonderheide Robert H. , Languino Lucia R. , Abrams Scott I. , Gabrilovich Dmitry I.
Published: June 2019

We have identified a precursor that differentiates into granulocytes in vitro and in vivo yet belongs to the monocytic lineage. We have termed these cells monocyte-like precursors of granulocytes (MLPGs). Under steady state conditions, MLPGs were absent in the spleen and barely detectable in the bone marrow (BM). In contrast, these cells significantly expanded in tumor-bearing mice and differentiated to polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs). Selective depletion of monocytic cells had no effect on the number of granulocytes in naive mice but decreased the population of PMN-MDSCs in tumor-bearing mice by 50%. The expansion of MLPGs was found to be controlled by the down-regulation of Rb1, but not IRF8, which is known to regulate the expansion of PMN-MDSCs from classic granulocyte precursors. In cancer patients, putative MLPGs were found within the population of CXCR1+CD15−CD14+HLA-DR−/lo monocytic cells. These findings describe a mechanism of abnormal myelopoiesis in cancer and suggest potential new approaches for selective targeting of MDSCs.