581 research outputs found
Investigation of the Effect of Rising Temperature and Traffic Loading on the Behaviour of Rigid Pavements to Minimise Maintenance Requirements â Case Study of Lebanese Roads
The aim of this project is to study the effects of high temperature on the performance of rigid pavements including that of Lebanese roads and to develop suitable design and maintenance approaches that enable such pavements to sustain high loading of temperature and traffic.
The objectives are to gain a deeper understanding of the condition and performance of existing highway rigid pavements and the need for a durable pavement. More specifically, to fully understand the effect of climate change in terms of temperature changes on rigid pavements and to identify structural layers configuration and material properties that enable the pavement to sustain high temperature and heavy traffic loading, and to develop more effective and sustainable rigid pavement structures to minimise maintenance requirements. The work also includes the design of suitable overlays to maintain and extend the life of the existing rigid pavements.
The methodology used to complete the project is by analysing pavement deflection and the effect of high temperature using specialised highway and structural analysis software, particularly the packages KENPAVE, STREETPAVE12 and ABAQUS.
The main findings are that fatigue and erosion are the two most significant failing scenarios for rigid pavement, but more specifically, as the temperature increases, the cracking index increases which may lead to fatigue failure. Finite element models and analyses were used to determine the distress caused by traffic loading and high temperature. This research has found that the main factors that strengthen the performance and sustainability of the rigid pavements under high temperature and traffic loading are: thicker slab, high modulus concrete, strong and thicker foundation layers and a subgrade with high CBR%, in addition to a strong and thicker overlay to extend the life of the pavement.
The key conclusions are that rising temperatures and high traffic loading have been identified as having a major effect on the performance of rigid pavement, leading to fatigue failure criteria. Erosion is also a common failure criterion which establishes itself at times of high traffic loading. It has been found here that the cracking index of the concrete slab increases when the air temperature changes from 20°C to 60°C. At higher temperatures and with thinner slabs, the cracking index occurrence increases. In conclusion, in Lebanon a minimum of 260 mm rigid pavement would be more suitable to reduce pavement failing under fatigue criteria
The Constructability of the Cheops Pyramid
Abstract
The aim of this paper is to forecast the methodology by which Cheops Pyramid as a historic building was built, based on notions of modular patterns discovered within the following planar illustrations, starting at the apex and descending to its grand base.
Some of Cheopsâ heritage in terms of form and function has existed for millennia, as its mark was recapped with a front line that was constructed thousands of years before. Such a voyage through the missing captures of the building techniques wouldnât have occurred without the incidental outcome that resulted from overlaying the various pixelated plans of block arrangements on the floor maps of Cheops. This building is believed to exhibit norms similar to those governing the balance between matter and void in the universe.
By assessing this historical masonry structure of Giza, we have come to find some regulatory approaches concerning how to asses the construction of such a building by predicting their interiors, spatial definitions, customs, and layouts. As there are no major records of their plans, the best practice anticipated in this paper is to modularize the figurative appearance of such buildings, by imitating themes of the repetitive patterns of past regional Egyptian architecture seen as pixels. This led to the fundamental solution to such a dilemma in building construction.
Keywords: Cheops, Pyramid, Balance, Historical Building
Nucleus accumbens volume is related to obesity measures in an ageâdependent fashion
Motivation theories of obesity suggest that one of the brain mechanisms underlying pathological eating and weight gain is the dysregulation of dopaminergic circuits. While these dysregulations occur likely at the microscopic level, studies on gray matter volume reported macroscopic differences associated with obesity. One region suggested to play a key role in the pathophysiology of obesity is the nucleus accumbens (NAcc). We performed a metaâanalysis of findings regarding NAcc volume and overweight/obesity. We additionally examined whether gray matter volume in the NAcc and other mesolimbic areas depends on the longitudinal trajectory of obesity, using the UK Biobank dataset. To this end, we analysed the data using a latent growth model, which identifies whether certain variables of interest (e.g. NAcc volume) is related to another variable's (BMI) initial values or longitudinal trajectories. Our metaâanalysis showed that, overall, NAcc volume is positively related to BMI. However, further analyses revealed that the relationship between NAcc volume and BMI is dependent on age. For younger individuals such relationship is positive, while for older adults it is negative. This was corroborated by our analysis in the UK Biobank dataset, which includes older adults, where we found that higher BMI was associated with lower NAcc and thalamus volume. Overall, our study suggests that increased NAcc volume in young age might be a vulnerability factor for obesity, while in the older age decreased NAcc volume with increased BMI might be an effect of prolonged influences of neuroinflammation on the brain
Treatment of tumour recurrence after resection of hepatocellular carcinoma. Analysis of 97 consecutive patients
OBJECTIVE:
To evaluate the long-term results of aggressive treatment of HCC recurrence.
METHODS:
Two hundred and nine consecutive patients underwent hepatic resection for HCC in our hospital. Tumour recurrence was diagnosed in 97 (51%) of the 190 patients with curative resection. Sixteen underwent hepatic resection: two right hepatectomies, one three-segmentectomy, one left hepatectomy, five two-segmentectomies, six segmental resections and one subsegmentectomy. Two patients with metastasis in the spine were submitted to a vertebral body resection. Twenty-five patients were treated with percutaneous ethanol injection or intra-arterial chemoembolization. Fifty-four patients with a poor performance status and liver function or multiple extra hepatic recurrences did not receive any treatment.
RESULTS:
There were no operative deaths. The postoperative mortality rate was 5.5% (one patient). The cumulative overall survival after the second resection was respectively 89%, 46% and 31% at 1, 3 and 5 years. There was a significant difference in survival between patients treated with repeat resection and those submitted to a non-surgical or conservative treatment (p<0.0001). There were no differences in operative deaths, postoperative mortality and morbidity between the first and second hepatic resection.
CONCLUSIONS:
Aggressive management with combined resection or loco regional therapy for intrahepatic recurrence and resection of isolated extra-hepatic recurrence may offer long-term survival in selected patients. Second liver resection for recurrence of HCC can be safely performed
Chirurgie hépatique mineure par laparoscopie en ambulatoire : étude rétrospective observationnelle
RĂ©sumĂ©Au cours de la derniĂšre dĂ©cennie, la chirurgie hĂ©patique laparoscopique (CHL) a connu un essor dans le monde entier. ParallĂšlement, la chirurgie ambulatoire a Ă©tĂ© dĂ©veloppĂ©e afin dâamĂ©liorer le confort des patients et de rĂ©duire les dĂ©penses de santĂ©. Lâobjectif de cette Ă©tude est de rapporter notre expĂ©rience prĂ©liminaire de la CHL en ambulatoire. Entre 1999 et 2014, 172 patients ont Ă©tĂ© opĂ©rĂ©s dans notre institution dâune CHL, incluant 151 rĂ©sections hĂ©patiques et 21 fenestrations de kystes hĂ©patiques. Tous les patients consĂ©cutifs, hautement sĂ©lectionnĂ©s, opĂ©rĂ©s dâune CHL en ambulatoire ont Ă©tĂ© inclus. Vingt patients ont Ă©tĂ© opĂ©rĂ©s dâune CHL en ambulatoire. Les indications Ă©taient des kystes hĂ©patiques dans 10 cas, un angiome hĂ©patique dans 3 cas, une hyperplasie nodulaire focale dans 3 cas, et une mĂ©tastase hĂ©patique de cancer colorectal dans 4 cas. La durĂ©e opĂ©ratoire mĂ©diane Ă©tait de 92minutes (dispersion : 50â240minutes). La perte sanguine mĂ©diane Ă©tait de 35mL (dispersion : 20â150mL). Il nâa pas Ă©tĂ© observĂ© de complication ni de rĂ©hospitalisation. Tous les patients Ă©taient hospitalisĂ©s en postopĂ©ratoire dans notre unitĂ© de chirurgie ambulatoire, et ont pu quitter lâĂ©tablissement 5 à 7heures aprĂšs la fin de la chirurgie. Le score mĂ©dian de douleur postopĂ©ratoire Ă la sortie Ă©tait de 3 (Ă©chelle visuelle analogique Ă 10 niveaux ; dispersion : 0â4). Le score mĂ©dian de qualitĂ© de vie Ă la premiĂšre consultation postopĂ©ratoire Ă©tait de 8 (dispersion : 6â10), et le score mĂ©dian de satisfaction esthĂ©tique Ă©tait de 8 (dispersion : 7â10). Cette sĂ©rie montre que la CHL ambulatoire est faisable et sĂ»re et chez des patients sĂ©lectionnĂ©s pour des interventions mineures.SummaryOver the last decade, laparoscopic hepatic surgery (LHS) has been increasingly performed throughout the world. Meanwhile, ambulatory surgery has been developed and implemented with the aims of improving patient satisfaction and reducing health care costs. The objective of this study was to report our preliminary experience with ambulatory minimally-invasive LHS. Between 1999 and 2014, 172 patients underwent LHS at our institution, including 151 liver resections and 21 fenestrations of hepatic cysts. The consecutive series of highly selected patients who underwent ambulatory LHS were included in this study. Twenty patients underwent ambulatory LHS. The indications were liver cysts in 10 cases, liver angioma in 3 cases, focal nodular hyperplasia in 3 cases, and colorectal hepatic metastasis in 4 cases. The median operative time was 92minutes (range: 50â240minutes). The median blood loss was 35mL (range: 20â150mL). There were no postoperative complications or re-hospitalizations. All patients were hospitalized after surgery in our ambulatory surgery unit, and were discharged 5â7hours after surgery. The median postoperative pain score at the time of discharge was 3 (visual analogue scale 0â10; range: 0â4). The median quality-of-life score at the first postoperative visit was 8 (range: 6â10) and the median cosmetic satisfaction score was 8 (range: 7â10). This series shows that, in selected patients, ambulatory LHS is feasible and safe for minor hepatic procedures
Regulation of ABCA1 expression and cholesterol efflux during adipose differentiation of 3T3-L1 cells.
Adipose cells specialized in energy storage, contain large intracellular triglyceride-rich lipid droplets, are enriched with free cholesterol, and express sterol-regulated transcription factors such as liver X receptor (LXR). The recent identification of the LXR-dependent ATP binding cassette transporter A1 (ABCA1) pathway for cholesterol release from peripheral cells has led us to address the question of the expression and function of ABCA1 in adipocytes. In 3T3-L1 adipose cells, we observed a strong induction of ABCA1 mRNA during adipose differentiation, but only limited variations in ABCA1 protein. Lipid efflux onto apolipoprotein A-I (apoA-I), which depends on ABCA1, was comparable in adipocytes and preadipocytes, demonstrating a differential regulation of ABCA1 mRNA and cholesterol efflux. We also found that total cell cholesterol remained stable during differentiation of 3T3-L1 cells, but membrane cholesterol was lower in adipocytes than in preadipocytes, suggesting redistribution of cholesterol to the lipid droplet. Finally, we show that under standard lipolytic stimulation, 3T3-L1 adipocytes do not release cholesterol onto apoA-I, a process that required long exposures to lipolytic agents (24 h). In conclusion, despite large induction of ABCA1 mRNA during differentiation, cholesterol efflux through the ABCA1 pathway remains limited in adipocytes and requires prolonged lipolysis. This is consistent with the view of the adipocyte behaving as a cholesterol sink, with plasma cholesterol-buffering properties
Nucleus accumbens volume is related to obesity measures in an ageâdependent fashion
Motivation theories of obesity suggest that one of the brain mechanisms underlying pathological eating and weight gain is the dysregulation of dopaminergic circuits. While these dysregulations occur likely at the microscopic level, studies on gray matter volume reported macroscopic differences associated with obesity. One region suggested to play a key role in the pathophysiology of obesity is the nucleus accumbens (NAcc). We performed a metaâanalysis of findings regarding NAcc volume and overweight/obesity. We additionally examined whether gray matter volume in the NAcc and other mesolimbic areas depends on the longitudinal trajectory of obesity, using the UK Biobank dataset. To this end, we analysed the data using a latent growth model, which identifies whether certain variables of interest (e.g. NAcc volume) is related to another variable's (BMI) initial values or longitudinal trajectories. Our metaâanalysis showed that, overall, NAcc volume is positively related to BMI. However, further analyses revealed that the relationship between NAcc volume and BMI is dependent on age. For younger individuals such relationship is positive, while for older adults it is negative. This was corroborated by our analysis in the UK Biobank dataset, which includes older adults, where we found that higher BMI was associated with lower NAcc and thalamus volume. Overall, our study suggests that increased NAcc volume in young age might be a vulnerability factor for obesity, while in the older age decreased NAcc volume with increased BMI might be an effect of prolonged influences of neuroinflammation on the brain
Working sick and out of sorts: a cross-cultural approach on presenteeism climate, organizational justice and workâfamily conflict
A climate of presenteeism has important effects on employee well-being and the organization itself. Our study, based on surveys of health sector employees in six different countries (Brazil, Ecuador, Lebanon, Portugal, Russia and Spain) examines whether organizational justice plays a mediating role in the relationship between a presenteeism climate in the organization and workâfamily conflict (WFC). Our results indicate that the perception of organizational justice and the presenteeism climate do influence WFC. Moreover, higher levels of WFC were found in non-Latin countries. This study contributes to the work attendance and life balance field by providing cross-cultural empirical evidence corroborating the effect of justice and presenteeism climate on the WFC.info:eu-repo/semantics/acceptedVersio
A Method Based on a Nonlinear Generalized Heisenberg Algebra to Study the Molecular Vibrational Spectrum
We propose a method, based on a Generalized Heisenberg Algebra (GHA), to
reproduce the anharmonic spectrum of diatomic molecules. The theoretical
spectrum generated by GHA allows us to fit the experimental data and to obtain
the dissociation energy for the carbon monoxide molecule. Our outcomes are more
accurate than the standard models used to study molecular vibrations, namely
the Morse and the -oscillator models and comparable to the perturbed Morse
model proposed by Huffaker \cite{hf}, for the first experimental levels. The
dissociation energy obtained here is more accurate than all previous models
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