bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of cyclic loading on performance of steel piles in sandy soil
Authors: Al-Neami Mohammed , Wasmi Mariam
Published: May 2018

This paper introduces an experimental study to clarify the response of steel pile models exposed to the cyclic loading. Thirty six models of two types of steel piles are tested (open ended pile and H-pile) with lengths equal to (30, 40, and 50) cm. Three diameters (2.5, 3.5, and 4.1) cm for open ended pipe pile and three flange widths (2.6, 3.6, and 4.4) cm for H-pile are investigated. Jacking technique is employed to installed piles models in dry sandy samples with two different relative densities (60% for medium sand 80% for dense sand). It is found that the pile geometry (diameter and length) with sand density have a high impact on the number of cycles. Analysis of results showed that increasing of pile diameter and relative density cause a reduction in the number of cycles when the length of steel pile models are fixed while variety of diameters of open ended pipe pile has a small effect on the number of cycles. It was found that pipe piles with open ended have more resistance to the cyclic loading compared with H piles under the same geometric conditions (pile diameter, embedded length and sand density) especially in medium sand. Finally, if the testing conditions are the same, number of cycles is decreased with increasing in amplitude loading
Effect of foundation embedment on the response of a multi-story building to earthquake excitation
Authors: Hamood Mohammed , Abid Sajjad
Published: May 2018

During an earthquake, the behaviour of any structure is affected not only by the superstructure response, but also by the response of the soil beneath. Recent structural failure patterns have indicated the significance of soil-structure interaction (SSI) effects. The present study focuses on SSI analysis considering the embedment depth of the foundation of a symmetric six stories reinforced concrete (RC)space bare frame building resting on stiff soil and subjected to seismic loading. The finite element analysis software ANSYS v17.2 is used. Time history (TH) analysis has been adopted. The Response in terms of lateral displacements, base shear forces, base moments and variation in natural time periods are calculated from the analysis of the soil foundation structure interaction (SFSI) model. Results are compared with that obtained from conventional method assuming rigid support at the base (fixed base) of the structure. The results show that the SFSI considering different embedment depths are significant in altering the seismic response of the multi-story building (MSB).
Ultimate capacity of piles penetrating in weak soil layers
Authors: Al-Obaidi Ahmed , Mahmood Pinar
Published: May 2018

A pile foundation is one of the most popular forms of deep foundations. They are routinely employed to transfer axial structure loads through the soft soil to stronger bearing strata. Piles generally used to increase the load carrying capacity of the foundation and reduce the settlement of the foundation. On the other hand, many cases in practice where piles pass through different layers of soil that contain weak layers located at different depths and extension, also some time cavities with a different shape, size, and depth are found. In this study, a total of 96 cases is considered and simulated in PLAXIS 2D program aiming to understand the influence of weak soil on the ultimate pile capacity. The piles embedded in the dense sand with a layer of weak soil at different extension and location. The cross section of the geometry used in this study was designed as an axisymmetric model with the 15-node element; the boundary condition recommended at least 5D in the horizontal direction, and (L+5D) in the vertical direction where D and L are the diameter and length of pile, respectively. The soil is modeled as Mohr-Coulomb, with five input parameters and the behavior of pile material represented by the linear elastic model. The results of the above cases are compared with the results found in a pile embedded in dense soil without weak layers or cavities. The results indicated that the existence of weak soil layer within the surrounding soil around the pile decreases the ultimate capacity. Furthermore, it has been found that increase in the weak soil width (extension) leads to reduction in the ultimate capacity of the pile. This phenomenon is applicable to all depth of weak soil. The influence of weak layer extension on the ultimate capacity is less when it is presentin the upper soil layers.
Improvement of engineering soil properties using non -traditional additives
Authors: Waheed Mohanned , Asmael Noor
Published: May 2018

Laboratory experiments are conducted to evaluate the effect of some non-traditional additives on the engineering properties of clayey soil, which show problematic phenomenon when used as a construction material. The conducted tests covered the influence of these additives on various parameters like consistency limits, compaction characteristics and CBR value. Two nontraditional stabilizers are selected in this study, polymers and phosphoric acid at three different percent which are (1%, 3% and 5%) of the dry soil weight. It is concluded that addition of the polymer to the clayey soil results in a slight increase in plastic limit while the liquid limit is not affected accompanied by a marginal decrease in the dry unit weight while the optimum moisture content remains unaffected. The addition of phosphoric acid to the clayey soil has no effect on its Atterberg limits. In general, it is observed that polymer is found to be ineffective as a stabilizer to improve clayey soils, especially in small amounts of about (3%). The phosphoric acid treated soil gained better improvement for all amounts of additive used. For (3%) acid treated soil the CBR is about (360%) compared to that of untreated soil, for that, it can be concluded that the improvement using phosphoric acid in the clay soils is a promising option and can be applied to solve the geotechnical stabilization problems.
Field observations and finite element 3-D analysis of soil displacements close to unsupported excavation
Authors: Aljorany Ala Nasir , Al-Qaisee Ghusoon Sadiq
Published: May 2018

Soil displacements due to unsupported deep excavation may cause severe damages to the nearby structures and foundations systems. Such excavations affect the state of stresses and displacements field of the surrounding soil. In this study, the soil displacements at five observation points were continuously monitored for23 days, which was the time period of excavation of about 7 m deep open tunnel. The reference points were installed on the ground surface at horizontal distance ranging from 1.25 to 3.25 m from tunnel excavation edge. The construction work was related to the project of developing the Army Channel/ Zeyouna section in the Eastern part of Baghdad City. The field observations indicate upward vertical displacement and outward lateral displacements during the first 10 days when the excavation depth was within 4 m. After that, the displacement trend was generally reversed. The displacement values were within 12 mm and vary from one observation point to another depending on the lateral distance of each point from excavation edge. The finite element package PLAXIS 3D was used to simulate the problem after obtaining the required soil parameters by an extensive site investigation. The analysis results in general, compare well with the field observations in terms of soil displacements at the reference points, especially during the first 10 days. This finding may reveal the reliability of the analysis results at other locations in the surrounding soil.
Some traffic characteristics of rural roads in Iraq
Authors: Al-Jameel Hamid Athab , Kadhim Ali Jihad
Published: May 2018

Now a days, modeling traffic characteristics are very important in evaluating traffic facilitates such normal section, weaving and merging sections. Lane changing and lane utilization are important traffic characteristics that are widely studied. Therefore this study is focused on both of these. The lane changing behavior affects the capacity and safety of roads. The distribution of vehicles among lanes of roadway is important in terms of different aspects such as safety, traffic management and even the structural design of roads. Field data have been collected from different rural roads. Two types of roads were studied; two-lane section and three-lane section. The results of analysis for collected data indicate that the driver behaviour is different in terms of lane utilization in Iraq from other countries and the same behaviour was found for lane changes also. Compared to other countries, Iraq has the lowest lane utilization and highest frequency of lane changes. These data are urgently needed nowadays for calibrating and validating the sophisticated programs such as simulated microscopic programs. These data are so important to mimic the reality for driver behaviors in rural roadways.
Improvement of traffic performance at intersections in Karbala city
Authors: Sofia Gandhi , Al-Haddad Abdulhaq , Al-Haydari Israa Saeed
Published: May 2018

This study deals with the evaluation of traffic performance at the road network around the old city of Karbala from the southern side, at Al-Tarbia Street and Fatima Al-Zahraa Street, through the evaluation of intersections performance. This is followed by suggestions of some improvement proposals, which vary from changing timing plan, geometric improvement, to change intersection type completely. The study area composed of seven intersections, three intersections are four legs signalized, and the other four are roundabouts. The video recording technique is used to collect the traffic data for 27 approaches. These data are abstracted from video films using EVENT program, and processed by prepared EXCEL sheets. While, the spot speed data for each entire link in the network are collected using pavement marking method. SYNCHRO software was used for evaluation and analysis of signalized intersections, suggestion of best timing plan, and coordination. SIDRA INTERSECTION software was used for evaluation and analysis of both signalized intersections and roundabouts. The best proposal was also evaluated for the target year.
Demand estimation of bus as a public transport based on gravity model
Authors: Asmael Noor , Waheed Mohanned
Published: May 2018

Bus as a public transport is a suitable service to meet the travel demand between any two zones. Baghdad faced with severe traffic problems along with the development in city size and economy. Passengers have to wait lots of time during commutation to work because of the serious traffic jams. In the last years, rate of car ownership has increased as income levels have gone up and cars have become a preferable mode of transport. Bus, as the only public mode of transport available, is suffering from inconvenience, slowness, and inflexibility. A big emphasis must be given to the public transport system because it introduces an active utilization of limited resources, energy and land. This study determines the demand of public routes for buses using boarding / alighting values to generate a model and assign these demand values to the bus network. Five public routes were selected to collect the required data. Ride check and Point check survey was conducted for each selected route. The results of this study were public demand assigned to the selected bus routes, dwell time, load factor and headway. It is observed that R1 and R3 have the heaviest travel demand; they need special study to improve bus performance and make better transit. The model developed with only limited data available to predict travel demand will assist transportation planners and related agencies in decision making.
Fresh and some mechanical properties of sifcon containing silica fume
Authors: Salih Shakir , Frayyeh Qais , Ali Manolia
Published: May 2018

Slurry infiltrated fiber concrete (SIFCON) is one of the recently developed construction material. SIFCON could be considered as a special type of fiber concrete with high fiber content. The matrix of SIFCON consists of flowing cement mortar or cement slurry. SIFCON has a very good potential for application in area where resistance to impact and high ductility are needed especially in designing the seismic retrofit, in the structures under impact and explosive effects and repair of structural reinforced concrete element. The main objective of this paper is to determine the effect of steel fiber content and silica fume (SF) cement replacement on the mechanical properties of SIFCON concrete. The percentage of SF replacement was 10% by weight of cement in SIFCON slurry, and three different volume fractions of hooked ended steel fiber (6, 8.5, and 11) % were used. The tested properties of SIFCON were compressive strength and splitting tensile strength which were carried out on standard size of cubes and cylinders respectively at the age of 7and 28 days. It was observed that the mechanical properties of SIFCON were affected in a positive manner by using silica fume as a partial replacement of cement and by adding steel fiber reinforcement in different percentages. The compressive and splitting tensile strength up to 83.7 MPa and 17.3MPa, respectively were obtained at the age of 28 days.
Shrinkage of high performance lightweight concrete exposed to hot-dry weather conditions
Authors: Ahmed Hisham , Khalil Wasan , Jumaa Nada H.
Published: May 2018

The main aim of this investigation is to study the combined effect of hot-dry weather conditions on the plastic and drying shrinkage of high performance lightweight aggregate concrete (HPLWAC) specimens, along with the other properties including, workability, setting time compressive and splitting strength. The experimental program including the use of fixed mix proportions and was carried out in a typical Iraqi summer day (under actual conditions) of different times during the day. The results indicate that the use of lightweight aggregate play a main role in decreasing the effect of hot dry weather on plastic shrinkage, as well as the plastic shrinkage strain of HPLWC specimens cast at 12:00 pm. less than that of normal weight aggregate concrete specimens by about 36.7%. While drying shrinkage of HPLWC specimens at initial ages up to 7 days was low and it increases with a higher rate at later ages.
Compressive strength improvement for recycled concrete aggregate
Authors: Mohammed Dhiyaa , Tobeia Sameh , Mohammed Faris , Hasan Sarah
Published: May 2018

Increasing amount of construction waste and, concrete remnants, in particular pose a serious problem. Concrete waste exist in large amounts, do not decay and need long time for disintegration. Therefore, in this work old demolished concrete is crashed and recycled to produce recycled concrete aggregate which can be reused in new concrete production. The effect of using recycled aggregate on concrete compressive strength has been experimentally investigated; silica fume admixture also is used to improve recycled concrete aggregate compressive strength. The main parameters in this study are recycled aggregate and silica fume admixture. The percent of recycled aggregate ranged from (0-100) %. While the silica fume ranged from (0-10) %. The experimental results show that the average concrete compressive strength decreases from 30.85 MPa to 17.58 MPa when the recycled aggregate percentage increased from 0% to 100%. While, when silica fume is used the concrete compressive strength increase again to 29.2 MPa for samples with 100% of recycled aggregate.
Assessment the thermal properties lightweight concreteproduced by using local industrial waste materials
Authors: AbdulAmeer Osama
Published: May 2018

In this research study of the thermal properties of light weight concrete produced from using two locally industrial wastes materials, to evaluate the thermal insulation, and some physical properties like strength of concrete (compressive and flexural tensile strength and variation of density of light weight concrete. Two types of wastes admixtures were used in this study, (chopped rubber, and wood sawdust) with (5%, 10%, 15% and 20%) percent of each one. Thermal conductivity, compressive strength, flexural tensile strength and variation of density have been examined for each specimen at all percentages of admixtures, and compare with the reference concrete specimens. Experimental test results indicated that using these types of wastes as replacement of fine aggregate in concrete significantly affects the thermal conductivity, compressive strength, flexural tensile strength (rise or fall out), especially at (5%) of adding materials, as well as utilization of additives in concrete to produce low density mixture with wood sawdust or as high density concrete when using rubber chopped in the concrete mixture.
Cost optimization for public school building projects during design stage using value engineering
Authors: Hassan Afrah , Yahya Majid
Published: May 2018

During the past ten years, various systems of building components have been applied in public school projects in Iraq, with no systematic method used for selection and evaluation, but only based on the designer’s experience. This paper displays evaluation and selection techniques based on value engineering methodology to find the optimal cost for school building projects in Iraq during design stage. The most important criteria for performance, constructability and sustainability criteria, which based on the Leadership in Energy and Environment Design used in this assessment were obtained from a survey of 49 professional designers and consultants, adoption of the Super Decisions Software Program, which uses analytical hierarchy process (AHP) for determining the relative importance of the main criteria and sub-criteria, that allows the decision-makers to evaluate the suitable alternatives of design for the external wall system in Iraq’s school buildings was built.
Characteristics of flow over the free overfall of triangular channel
Authors: Irzooki Raad , Hasan Safa
Published: May 2018

In the present paper, the effects of side slopes, bed slopes and bed roughness on the flow over free overfalls in triangular channels have been studied experimentally. For this purpose, three models of triangular channels with free overfalls have been constructed and fixed in a 6m length laboratory flume. These three models had length of 244cm with different values of side slopes (Z) (0.8(H):1(V), 1:1 and 1.33:1). Each one of these models had four different bed slopes (S) (0, 0.0041, 0.0082 and 0.0123). For each bed slope, the bed was roughened with three particle sizes of sand (ds) (1.18mm, 2.36mm, and 4.75mm). The experimental testing program included sixteen series of experiments for each model. Four of them were for smooth beds and twelve for rough beds. A total of forty eight experiments were tested for different rates of discharge (Q). Experimental results of all models showed that Froude number (Frb) of flow decreases with the increasing of end depth ratio values (yb/yc) for different bed roughness, different bed slopes. The relations between the brink depth (yb) and the critical depth (yc) were found to be a simple linear formula for various bottom slope and different bottom roughness. An empirical expression was obtained for the flow over the free overfall in triangular channels for different bed slopes and roughness. The results of the present study have been compared with studies were obtained by other investigators, the comparison shows a very good agreement between them.
Analytical predictions of moment curvature relationship of steel beam columns under fire attack
Authors: Al-Thairy Haitham
Published: May 2018

Fire attack is one of the worst scenarios that may cause catastrophic consequences of steel buildings such as progressive collapse and failure. Current design codes and standards have addressed fire as one of the extreme loading conditions to be accounted for in the design of buildings. However, most of the approaches and procedures suggested by these codes and standards still lack accuracy and rationality. The purpose of this paper is to develop an analytical approach to predict the elastic-plastic moment-curvature relationship of steel beam - columns section under elevated temperature. The analytical method was derived based on dividing the steel section to layers and integrating the resistance moment equation of each layer in terms of the section curvature taking into account the effect of elevated temperature on the material properties of the steel by using EC3 reduction factors of the yield stress and modulus of elasticity. The suggested method has been validated against numerical simulation results. Validation results have shown the reliability of the suggested method to predict the resistance moment - curvature relationship of steel beam-column members at different elevated temperatures and under different values of the axial compressive force. The suggested methods may be used to develop more accurate design approaches for steel beam columns under fire condition.
Behavior of reinforced concrete slender rectangular columns under uniaxial loading
Authors: Muhammad Bassman
Published: May 2018

Two proposed formulae are presented to obtain the reinforced concrete slender column capacity. Reinforced concrete slender columns are used more nowadays than in the past 30 years because of development of engineering materials. Structural engineers that adopted the ACI 318M Code know that the design of this type of columns is more tedious than short ones. This research proposes two formulae that reflect the ultimate strength of cross section of slender columns, one for the axial and the second for the bending moment. Case study of 656250 columns is generated to cover most variable properties of columns, analyzed using MATLAB (R2017a) Program to obtain the ultimate strength of cross section then compared to the strength of slender columns.
Removal of cadmium Cd(ii) and silver Ag(i) from aqueous solutions by nano activated alumina. part i: batch adsorption experiments
Authors: Wadie Alaa , Al-Khawaja Enas
Published: May 2018

The extent of removal of heavy metal ions cadmium Cd(II) and silver Ag(I) in single and binary system by adsorption on alumina has been investigated. Adsorption experiments were performed in batch technique from synthetic solutions using high purity nano activated alumina prepared in laboratory as adsorbent for heavy metals remove. Several experimental parameters that affect the extent of adsorption of the metal ions of interest have been investigated such as adsorbent dosage, concentration of the adsorbate, contact time, agitation speed and pH of the system under study. The equilibrium nature of the adsorption of the metal ions at different concentrations has been followed by Freundlich and Langmuir adsorption isotherms. Correlation coefficients (R2) derived from these plots are (0.965) for cadmium Cd(II) and (0.966) for silver Ag(I). This work proposes a cost-effective method for the efficient removal of Cd(II) and Ag(I) from aqueous solutions. The conditions required for effective removal have been optimized.
Metallopeptidases ofToxoplasma gondii:in silicoidentification and gene expression
Authors: Escotte-Binet Sandie , Huguenin Antoine , Aubert Dominique , Martin Anne-Pascaline , Kaltenbach Matthieu , Florent Isabelle , Villena Isabelle
Published: May 2018

Metallopeptidases are a family of proteins with domains that remain highly conserved throughout evolution. These hydrolases require divalent metal cation(s) to activate the water molecule in order to carry out their catalytic action on peptide bonds by nucleophilic attack. Metallopeptidases from parasitic protozoa, includingToxoplasma, are investigated because of their crucial role in parasite biology. In the present study, we screened theT. gondiidatabase using PFAM motifs specific for metallopeptidases in association with the MEROPS peptidase Database (release 10.0). In all, 49 genes encoding proteins with metallopeptidase signatures were identified in theToxoplasmagenome. An Interpro Search enabled us to uncover their domain/motif organization, and orthologs with the highest similarity by BLAST were used for annotation. These 49 Toxoplasmametallopeptidases clustered into 15 families described in the MEROPS database. Experimental expression analysis of their genes in the tachyzoite stage revealed transcription for all genes studied. Further research on the role of these peptidases should increase our knowledge of basicToxoplasmabiology and provide opportunities to identify novel therapeutic targets. This type of study would also open a path towards the comparative biology of apicomplexans.
DEGEA-Curriculum: Sedierung und Notfallmanagement in der Endoskopie für Endoskopiepflege- und Endoskopieassistenzpersonal – Update 2018
Authors: Beilenhoff Ulrike , Engelke Monika , Kern-Waechter Elisabeth , Pfeifer Ute , Riphaus Andrea , Wietfeld Kornelia , Maeting Silvia
Published: May 2018

Das DEGEA-Curriculum, basierend auf der S3-Leitlinie „Sedierung in der gastrointestinalen Endoskopie, bietet einen qualitätsorientierten Rahmen, um Endoskopiefachpersonal in Sedierung und Notfallmanagement zu schulen. Dieses Curriculum wurde nun aktualisiert.
Patienten mit eingeschränkter Nierenfunktion
Authors: van der Giet Markus
Published: May 2018

Bei eingeschränkter Nierenfunktion ist eine arterielle Hypertonie ein häufiger Begleiter. Seit über 2 Jahrzehnten ist bekannt, dass ein nicht kontrollierter
Blutdruck mittelfristig zu einem schnelleren Nierenfunktionsverlust führt und damit auch eine Nierenersatztherapie fast unweigerlich droht. In den letzten
Jahrzehnten hat man über klinische Studien versucht, den idealen Zielblutdruckwert zu ermitteln, der die Progression der Niereninsuffizienz maximal reduziert
und damit gleichzeitig auch die kardiovaskuläre Morbidität und Mortalität positiv beeinflusst. In den aktuellen Leitlinien der Europäischen
Hypertoniegesellschaft oder auch von KDIGO wurde ein systolisches Blutdruckziel von unter 140 mmHg zur optimalen Behandlung von nierenkranken Hypertonikern
definiert. Aber nach Analyse der SPRINT-Studie gibt es sehr gute Hinweise, dass eine Blutdrucksenkung auf unter 130 mmHg systolisch auch für nierenkranke
Patienten Sinn macht. Eine erste Leitlinie US-amerikanischer kardiologischer/nephrologicher/hypertensiologischer Fachgesellschaften hat dieses Ziel von unter
130/80 mmHg bei Nierenkrankheit auch bereits definiert.
Dialysepatienten
Authors: Gohlisch Christopher , van der Giet Markus
Published: May 2018

Blutdruckprobleme sind beim Dialysepatienten ein alltägliches Problem. Während wir mittlerweile sehr gut wissen, welche Ziele wir in der Blutdrucktherapie beim
nierengesunden Patienten anstreben, so sind die entsprechenden Zielwerte für Dialysepatienten deutlich weniger klar. Durch das terminale Versagen der Niere
erscheint der kardiovaskuläre Risikofaktor Hypertonie entschärft zu werden, da andere, urämiebedingte Risikofaktoren für die kardiovaskuläre Mortalität
dominanter werden. Darüber hinaus ändert sich die Blutdruckregulation bei Dialysepatienten erheblich. In der vorliegenden Übersicht wird zusammengefasst, wann
und wie bei Dialysepatienten der Blutdruck gemessen werden sollte. Außerdem werden neben den möglicherweise zu erreichenden Blutdruckzielen auch die derzeit
bekannten Behandlungsstudien zusammenfassend dargestellt.
Full-thickness resection with an over-the-scope device: possible translocation of adenoma tissue in a case of an incomplete resection at the appendix
Authors: Dumoulin Franz , Gorris Dominik , Berger Susanne , Hildenbrand Ralf , Sido Bernd
Published: May 2018

Background and study aims Clip-assisted endoscopic full-thickness resection has great potential for treatment of difficult-to-resect colorectal neoplasia. Here, we report on endoscopic full-thickness resection at the appendiceal orifice with the appendix in situ requiring emergency surgery due to acute appendicitis. Final histopathology showed appendicitis and residual serrated adenoma within the appendiceal stump, but unexpectedly, also a displaced adenoma fragment at the serosal surface of the cecum. Given the transmural placement of the clip prior to snare resection, translocation of neoplastic tissue to the extra luminal site in cases of incomplete adenoma/carcinoma resection could be a concern.
The clinical significance and synchronous polyp burden of large (≥ 20 mm) sessile serrated polyps in patients without serrated polyposis syndrome
Authors: Desomer Lobke , Tate David J. , Jayanna Mahesh , Pellise Maria , Awadie Halim , Burgess Nicholas G. , McLeod Duncan , Mahajan Hema , Lee Eric Y. T. , Williams Stephen J. , Bourke Michael J.
Published: May 2018

Background Sessile serrated polyps (SSPs) are important precursors of colorectal carcinoma and interval cancer. Large SSPs (≥ 20 mm) outside the definition of serrated polyposis syndrome (SPS) have not been studied in comparison with SPS. We aimed to describe the characteristics of patients with large SSPs in this context.

Methods Patients with at least one SSP (≥ 20 mm) were eligible. Data from three consecutive colonoscopies were used to compare clinical and endoscopic characteristics in three patient groups: SPS, a solitary large SSP, and patients with at least two SSPs without fulfilling the criteria for SPS (oligo-SSP). Data on the diagnostic colonoscopy were collected retrospectively, whereas the remaining data was collected prospectively.

Results 67/146 patients (45.9 %) had SPS, 53/146 (36.3 %) had a solitary SSP, and 26/146 (17.8 %) were categorized as oligo-SSP. Personal (16.4 %, 9.4 %, and 11.5 %, respectively) and family (17.9 %, 17.0 %, and 23.1 %, respectively) history of colorectal carcinoma did not differ significantly between groups. Polyp burden was greater in SPS compared with solitary SSP but was not different from oligo-SSP (advanced adenomas: SPS 32.8 % vs. solitary SSP 9.4 % [P = 0.002] vs. oligo-SSP 34.6 % [P = 0.87]; ≥ 10 conventional adenomas: 11.9 % vs. 0 % [P = 0.01] vs. 3.8 % [P = 0.44], respectively). Dysplasia in large SSPs was frequent in all groups (41.1 % overall). SPS was recognized by referring endoscopists in only 9.0 % of cases.

Conclusion Patients with oligo-SSPs have similar synchronous polyp burden and clinical characteristics as patients with SPS and may require similar surveillance. Modification of the criteria for the diagnosis of SPS to include this group seems warranted. Patients with a solitary SSP have a lower risk of synchronous polyps, including advanced adenomas. Larger studies are warranted to determine whether these patients may return to standard surveillance following complete examination and clearance of the colon.
A Multicenter Analysis Examining Patients Undergoing Conversion of Implant-based Breast Reconstruction to Abdominally based Free Tissue Transfer
Authors: Zhao Ruya , Tran Bao , Doval Andres , Broadwater Gloria , Buretta Kate , Orr Jonah , Lee Bernard , Hollenbeck Scott
Published: May 2018

Background Breast implant placement is the most common method for postmastectomy reconstruction. For patients who develop complications associated with implant-based reconstruction, additional surgeries may be challenging. This study examined implant-based reconstruction failure in patients undergoing salvage with abdominal free tissue transfer.

Methods We conducted an Institutional Review Board approved, multicenter retrospective study of patients with implant-based primary breast reconstruction followed by implant removal and subsequent abdominal free tissue transfer between 2006 and 2016. Patient demographics, treatment details, and complications were evaluated. Severity of implant failure was graded as either (1) not severe (delayed salvage reconstruction) or (2) severe (immediate salvage reconstruction).

Results Between 2006 and 2016, 115 patients with 180 mastectomy defects underwent primary implant-based reconstruction with subsequent implant removal and abdominally based free tissue reconstruction. Of these, 68 were delayed and 47 were immediate salvage reconstruction. Factors leading to elective removal were capsular contracture, asymmetry, and implant malposition. Factors leading to obligatory removal were infection, delayed wound healing, and implant extrusion. Postmastectomy radiation was significantly associated with immediate salvage reconstruction (p < 0.001, odds ratio = 3.9) as were large volume implants (p = 0.06). Deep inferior epigastric perforator flaps comprised 78.3% of all abdominally based free tissue reconstructions, while muscle-sparing transverse rectus abdominus myocutaneous flaps comprised 18.3%. Overall flap failure rate was 2.6% (2.94% delayed and 2.13% immediate salvage reconstruction; p = 1.0).

Conclusion Our findings suggest that abdominal free tissue transfer remains a safe and effective salvage modality for implant-based breast reconstruction failure. Patients with severe implant failure were more likely to have received radiation. Surgeons should remain cognizant of this during care of patients.
Pankreas-Stent-Dislokation und frustrane endoskopische Bergungsversuche: OP indiziert?
Authors: Hemmel Markus , Reitinger Steffen , Sackmann Michael , Schäfer Claus
Published: May 2018

Die seit Langem eingesetzten Pankreasstents migrieren zu 7,5 % nach distal, zu 5,2 % nach proximal. Trotz verschiedener Möglichkeiten und Instrumente die nach proximal migrierten Stents zu bergen, gelingt dies nur in ca. 80 % der Fälle. Aufgrund der Folgeschäden und Risiken durch den verbleibenden Stent im Pankreasgang im Sinne einer chronischen Pankreatitis mit konsekutiver OP-Indikation bzw. mit erhöhtem Karzinomrisiko, rieten wir unserem Patienten, in Anbetracht der heute überschaubaren perioperativen Risiken, zur operativen Bergung.
Standardisierte Befundung und Dokumentation der Kontrastmittelsonografie der Leber (CEUS LI-RADS)
Authors: Potthoff Andrej , Helmberger Thomas , Ignee Andre , Willmann Juergen K. , Dietrich Christoph F. ,   on behalf of the CEUS LI-RADS Working Group
Published: May 2018

In der Abklärung von hepatozellulären Karzinomen (HCCs) bei Hochrisikopatienten wurde zur standardisierten Befundung und Dokumentation der Kontrastmittel-Computertomografie (CECT) und Kontrastmittel-Magnetresonanztomografie (CEMRT) vor wenigen Jahren das „Liver Imaging Reporting and Data System” (LI-RADS) durch das American College of Radiology (ACR) erstellt. Die LI-RADS-Kategorisierung wird zur Klassifikation von Leberläsionen in der Leberzirrhose als sicher benigne (LR-1), intermediär (LR2 – 4) bis zu „definitiv HCC“ (LR-5) beurteilt. Seit 2014 wurde die LI-RADS-Klassifikation durch eine Arbeitsgruppe von internationalen Radiologen und Hepatologen auf die Kontrastmittelsonografie erweitert. Zeitgleich mit der Zulassung des Kontrastmittels SonoVue™ (in den USA Lumason™) wurde die Klassifikation 2016 in die LI-RADS Kategorisierung integriert und wird in diesem Artikel erläutert (CEUS-LI-RADS).
Fine topology and locally Minkowskian manifolds
Authors: Agrawal Gunjan , Sinha Soami Pyari
Published: May 2018

Fine topology is one of the several well-known topologies of physical and mathematical relevance. In the present paper, it is obtained that the nonempty open sets of different dimensional Minkowski spaces with the fine topology are not homeomorphic. This leads to the introduction of a new class of manifolds. It turns out that the technique developed here is also applicable to some other topologies, namely, the s-topology, space topology, f-topology, and A-topology.
Remarks on the slow relaxation for the fractional Kuramoto model for synchronization
Authors: Ha Seung-Yeal , Jung Jinwook
Published: May 2018

The collective behavior of an oscillatory system is ubiquitous in our nature, and one interesting issue in the dynamics of many-body oscillatory systems is the relaxation dynamics toward relative equilibria such as phase-locked states. For the Kuramoto model, relaxation dynamics occurs exponentially fast for generic initial data. However, some synchronization phenomena observed in our nature exhibit a slow subexponential relaxation. Thus, as one of the possible attempts for such slow relaxation, a second-order inertia term was added to the Kuramoto model in the previous literature so that the resulting second-order model can exhibit a slow relaxation dynamics for some range of inertia and coupling strength. In this paper, we present another Kuramoto type model exhibiting a slow algebraic relaxation. More precisely, our proposed model replaces the classical derivative by the Caputo fractional derivative in the original Kuramoto model. For this new model, we present several sufficient frameworks for fractional complete synchronization and practical synchronization.
Engineering the electronic band structures of novel cubic structured germanium monochalcogenides for thermoelectric applications
Authors: Ul Haq Bakhtiar , AlFaify S. , Ahmed R. , Butt Faheem K. , Laref A. , Goumri-Said Souraya , Tahir S. A.
Published: May 2018

Germanium mono-chalcogenides have received considerable attention for being a promising replacement for the relatively toxic and expensive chalcogenides in renewable and sustainable energy applications. In this paper, we explore the potential of the recently discovered novel cubic structured (π-phase) GeS and GeSe for thermoelectric applications in the framework of density functional theory coupled with Boltzmann transport theory. To examine the modifications in their physical properties, the across composition alloying of π-GeS and π-GeSe (such as π-GeS1-xSex for x =0, 0.25, 0.50, 0.75, and 1) has been performed that has shown important effects on the electronic band structures and effective masses of charge carriers. An increase in Se composition in π-GeS1-xSex has induced a downward shift in their conduction bands, resulting in the narrowing of their energy band gaps. The thermoelectric coefficients of π-GeS1-xSex have been accordingly influenced by the evolution of the electronic band structures and effective masses of charge carriers. π-GeS1-xSex features sufficiently larger values of Seebeck coefficients, power factors and figures of merit (ZTs), which experience further improvement with an increase in temperature, revealing their potential for high-temperature applications. The calculated results show that ZT values equivalent to unity can be achieved for π-GeS1-xSex at appropriate n-type doping levels. Our calculations for the formation enthalpies indicate that a π-GeS1-xSex alloying system is energetically stable and could be synthesized experimentally. These intriguing characteristics make π-GeS1-xSex a promising candidate for futuristic thermoelectric applications in energy harvesting devices.
Optical properties of flexible fluorescent films prepared by screen printing technology
Authors: Chen Yan , Ke Taiyan , Chen Shuijin , He Xin , Zhang Mei , Li Dong , Deng Jinfeng , Zeng Qingguang
Published: May 2018

In this work, we prepared a fluorescent film comprised phosphors and silicone on flexible polyethylene terephthalate (PET) substrate using a screen printing technology. The effects of mesh number and weight ratio of phosphors to silicone on the optical properties of the flexible films were investigated. The results indicate that the emission intensity of the film increase as the mesh decreased from 400 to 200, but the film surface gradually becomes uneven. The fluorescent film with high emission intensity and smooth surface can be obtained when the weight ratio of phosphor to gel is 2:1, and mesh number is 300. The luminous efficiency of the fabricated LEDs combined the fluorescent films with 460 nm Ga(In)N chip module can reach 75 lm/W. The investigation indicates that the approach can be applied in the remote fluorescent film conversion and decreases the requirements of the particle size and the dispersion state of fluorescent materials.
Molecular simulation of the water-triolein-oleic acid mixture: Local structure and thermodynamic properties
Authors: Couallier E. , Riaublanc A. , David Briand E. , Rousseau B.
Published: May 2018

An artificial oil-in-water emulsion analogous to those found in bioresources or food matrices is simulated and studied experimentally. It is composed of one of the major natural free fatty acids (the oleic acid, OA) and the corresponding triacylglyceride (trioleic glyceride, or triolein, GTO). Because of the large time and length scales involved, the molecular simulations are done with the Martini force field, a coarse-grained model. This allowed us to study the water–OA–GTO system at different compositions with more than 20 000 molecules and up to 2 μs. Interfacial tension was measured using the pendant drop method and compared with molecular simulation results. We observe very good agreement at high OA concentrations and deviations up to 15% at low OA concentrations. The water solubility in the lipid phase is in fair agreement with experiments, between 0.03 and 0.32 mol/l, rising with the OA content. The area occupied by OA and GTO at the interface between water and the pure product fitted with experimental data (AOA = 36.6 Å2 and AGTO = 152.1 Å2). The consistency between simulation and experimental results allowed a structural analysis of the interface. A bilayer structure of the lipids at the water/oil interface is proposed, containing preferentially oleic acid but also triolein. Through all these results, the usefulness of coarse-grained simulation for the description of water–oil interfacial organization is demonstrated. This method will be used later to bring local information on the organization of target compounds, necessary in biomass fractionation processes or food additive formulations, for example.
Altering thermal transport by strained-layer epitaxy
Authors: Majdi Tahereh , Pal Souvik , Hafreager Anders , Murad Sohail , Sahu Rakesh P. , Puri Ishwar K.
Published: May 2018

Since strain changes the interatomic spacing of matter and alters electron and phonon dispersion, an applied strain can modify the thermal conductivity k of a material. We show how the strain induced by heteroepitaxy is a passive mechanism to change k in a thin film. Molecular dynamics simulations of the deposition and epitaxial growth of ZnTe thin films provide insights into the role of interfacial strain in the conductivity of a deposited film. ZnTe films grow strain-free on lattice-matched ZnTe substrates, but similar thin films grown on a lattice-mismatched CdTe substrate exhibit ∼6% biaxial in-plane tensile strain and ∼7% uniaxial out-of-plane compressive strain. In the T = 700 K–1100 K temperature range, the conductivities of strained ZnTe layers decrease to ∼60% of their unstrained values. The resulting understanding of dk/dT shows that strain engineering can be used to alter the performance of a thermal rectifier and also provides a framework for enhancing thermoelectric devices.
Reactive diffusion in the presence of a diffusion barrier: Experiment and model
Authors: Mangelinck D. , Luo T. , Girardeaux C.
Published: May 2018

Reactions in thin films and diffusion barriers are important for applications such as protective coatings, electrical contact, and interconnections. In this work, the effect of a barrier on the kinetics of the formation for a single phase by reactive diffusion is investigated from both experimental and modeling point of views. Two types of diffusion barriers are studied: (i) a thin layer of W deposited between a Ni film and Si substrate and (ii) Ni alloy films, Ni(1%W) and Ni(5%Pt), that form a diffusion barrier during the reaction with the Si substrate. The effect of the barriers on the kinetics of δ-Ni2Si formation is determined by in situ X ray diffraction and compared to models that explain the kinetic slowdown induced by both types of barrier. A linear parabolic growth is found for the deposited barrier with an increasing linear contribution for increasing barrier thickness. On the contrary, the growth is mainly parabolic for the barrier formed by the reaction between an alloy film and the substrate. The permeability of the two types of barrier is determined and discussed. The developed models fit well with the dedicated model experiments, leading to a better understanding of the barrier effect on the reactive diffusion and allowing us to predict the barrier behaviour in various applications.
Chemical potential calculations in non-homogeneous liquids
Authors: Perego Claudio , Valsson Omar , Parrinello Michele
Published: May 2018

The numerical computation of chemical potential in dense non-homogeneous fluids is a key problem in the study of confined fluid thermodynamics. To this day, several methods have been proposed; however, there is still need for a robust technique, capable of obtaining accurate estimates at large average densities. A widely established technique is the Widom insertion method, which computes the chemical potential by sampling the energy of insertion of a test particle. Non-homogeneity is accounted for by assigning a density dependent weight to the insertion points. However, in dense systems, the poor sampling of the insertion energy is a source of inefficiency, hampering a reliable convergence. We have recently presented a new technique for the chemical potential calculation in homogeneous fluids. This novel method enhances the sampling of the insertion energy via well-tempered metadynamics, reaching accurate estimates at very large densities. In this paper, we extend the technique to the case of non-homogeneous fluids. The method is successfully tested on a confined Lennard-Jones fluid. In particular, we show that, thanks to the improved sampling, our technique does not suffer from a systematic error that affects the classic Widom method for non-homogeneous fluids, providing a precise and accurate result.
Experimental and numerical study on the onset of natural convection in a cavity open at the top
Authors: Saxena Ashish , Kishor Vimal , Singh Suneet , Srivastava Atul
Published: May 2018

The onset of natural convection in a 2D air filled cavity open at the top with adiabatic side walls is studied. The numerical model shows the existence of weak convective flow near the top corner of a cavity due to the thermal gradient between the walls and the atmosphere even at low Rayleigh numbers, as also confirmed by the interferometry-based experimental data. Additionally, a thermally stratified layer is formed on the lower side of the cavity. The onset of convection is seen to be dependent on the interaction of these two features in the cavity. Results of the study show that in low aspect ratio cavities, the thermally stratified layers are clearly formed and are not significantly disturbed by the flow at the corners. The onset of convection takes place in these earlier thermally stratified layers beyond a certain Rayleigh number. This convective movement is characterized by a sudden jump in the heat transfer coefficient at a critical Rayleigh number. However, for high aspect ratio cavities, the flow at the corners has significant influence on the stratified layers and results in a decrease in the value of critical Rayleigh number. Beyond a certain aspect ratio, these layers cannot be formed and hence there is no onset of convection. Simulations as well as the interferometric measurements show an inherent symmetry in the corner flows, which was seen to breakdown due to the flow-induced instabilities in the thermally stratified layers for Rayleigh numbers greater than the critical value.
Mimicking graphene physics with a plane hexagonal wire mesh
Authors: Dautova Yulia N. , Shytov Andrey V. , Hooper Ian R. , Sambles J. Roy , Hibbins Alastair P.
Published: May 2018

A hexagonal metallic-wire mesh is fabricated and experimentally characterized to demonstrate graphene-physics in an electromagnetic analogue. In contrast to previous studies, our structure has a smaller ratio of out-of-plane to in-plane dimensions, more akin to real graphene. This allows for the development of a simple analytical treatment using equivalent electric circuit theory, and we demonstrate that the predicted dispersion curves of the supported eigenmodes agree well with those obtained from experimental measurements.