AIM To evaluate the evolution, trends in surgical approaches a n d r e c o n s t r u c t i o n t e c h n i q u e s, a n d i m p o r t a n t lessons learned from performing 1000 consecutive pancreaticoduodenectomies(PD...AIM To evaluate the evolution, trends in surgical approaches a n d r e c o n s t r u c t i o n t e c h n i q u e s, a n d i m p o r t a n t lessons learned from performing 1000 consecutive pancreaticoduodenectomies(PDs) for periampullary tumors.METHODS This is a retrospective review of the data of all patients who underwent PD for periampullary tumor during the period from January 1993 to April 2017. The data were categorized into three periods, including early period(1993-2002), middle period(2003-2012), and late period(2013-2017).RESULTS The frequency showed PD was increasingly performed after the year 2000. With time, elderly, cirrhotic and obese patients, as well as patients with uncinate process carcinoma and borderline tumor were increasingly selected for PD. The median operative time and postoperative hospital stay decreased significantly over the periods. Hospital mortality declined significantly, from 6.6% to 3.1%. Postoperative complications significantly decreased, from 40% to 27.9%. There was significant decrease in postoperative pancreatic fistula in the second 10 years, from 15% to 12.7%. There was a significant improvement in median survival and overall survival among the periods.CONCLUSION Surgical results of PD significantly improved, with mortality rate nearly reaching 3%. Pancreatic reconstruction following PD is still debatable. The survival rate was also improved but the rate of recurrence is still high, at 36.9%.展开更多
AIM:To evaluate effective alternative antibiotics in treatment of cefotaxime-resistant spontaneous bacterial peritonitis.METHODS:One hundred cirrhotic patients with spontaneous bacterial peritonitis [ascitic fluid pol...AIM:To evaluate effective alternative antibiotics in treatment of cefotaxime-resistant spontaneous bacterial peritonitis.METHODS:One hundred cirrhotic patients with spontaneous bacterial peritonitis [ascitic fluid polymorphonuclear cell count(PMNLs) ≥ 250 cells/mm 3 at admission] were empirically treated with cefotaxime sodium 2 g/12 h and volume expansion by intravenous human albumin.All patients were subjected to history taking,complete examination,laboratory tests(including a complete blood cell count,prothrombin time,biochemical tests of liver and kidney function,and fresh urine sediment),chest X-ray,a diagnostic abdominal paracentesis,and the sample subjected to total and differential cell count,chemical examination,aerobic and anaerobic cultures.Patients were divided after 2 d by a second ascitic PMNL count into group Ⅰ;patients sensitive to cefotaxime(n = 81),group Ⅱ(n = 19);cases resistant to cefotaxime(less than 25% decrease in ascitic PMNL count).Patients of group Ⅱ were randomly assigned into meropenem(n = 11) or levofloxacin(n = 8) subgroups.All patients performed an end of treatment ascitic PMNL count.Patients were considered improved when:PMNLs decreased to < 250 cells/mm 3,no growth in previously positive culture cases,and improved clinical manifestations with at least 5 d of antibiotic therapy.RESULTS:Age,sex,and Child classes showed no significant difference between group Ⅰ and group Ⅱ.Fever and abdominal pain were the most frequent manifestations and were reported in 82.7% and 80.2% of patients in group Ⅰ and in 94.7% and 84.2% of patients in group Ⅱ,respectively.Patients in group Ⅱ had a more severe ascitic inflammatory response than group Ⅰ and this was demonstrated by more ascitic lactate dehydrogenase(LDH) [median:540 IU/L(range:150-1200 IU/L) vs median:240 IU/L(range:180-500 IU/L),P = 0.000] and PMNL [median:15 000 cell/mm 3(range:957-23 822 cell/mm 3) vs 3400 cell/mm 3(range:695-26 400 cell/mm 3),P = 0.000] counts.Ascitic fluid culture was positive in 32% of cases.Cefot展开更多
Induction motors （IMs） are commonly used in various industrial applications. To improve energy con- sumption efficiency, a reliable IM health condition moni- toring system is very useful to detect IM fault at its ea...Induction motors （IMs） are commonly used in various industrial applications. To improve energy con- sumption efficiency, a reliable IM health condition moni- toring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is pro- posed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are syn- thesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air- gap eccentricity diagnosis. The effectiveness of the pro- posed harmonic synthesis technique is examined experi- mentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.展开更多
AIM:To analyze cases of obstruction of the nasolacrimal duct which creates a fertile environment for secondary bacterial Infection and can result in dacryocystitis,which is a constant threat to cornea and orbital soft...AIM:To analyze cases of obstruction of the nasolacrimal duct which creates a fertile environment for secondary bacterial Infection and can result in dacryocystitis,which is a constant threat to cornea and orbital soft tissue and a potential source of endophthalmitis following intraocular surgery.The majority of obstructions of the lacrimal excretory outflow system are acquired ones occurring in adulthood and involving the distal parts of the system.Acquired obstruction may be primary/idiopathic or secondary to a wide variety of infectious,inflammatory,traumatic,mechanical,toxic or neoplastic causes mimicking idiopathic inflammation.These cases are treated by dacryocystorhinostomy(DCR).METHODS:The present study was conducted to determine the histopathologic,immunohistochemical and current microbiologic characteristics of lacrimal sac specimens in patients undergoing external dacryocystorhinostomy.RESULTS:Non-specific lacrimal sac pathology was present in all 33 cases and 81.8%of the cases showed moderate chronic inflammation with a chronic inflammatory score(CIS)ranging between 4 and 6,whereas 12.12%showed severe inflammatory changes with a CIS of 7.Mild degree of inflammation was seen in6.06%with a CIS of 3.The total prevalence of grampositive,gram-negative,and culture-negative samples were 59.4%,37.5%,and 3%respectively.CONCLUSION:Non-specific chronic inflammation withfibrosis is indeed the most commonly reported histopathological finding in lacrimal sac wall biopsy specimens.展开更多
AIM: To investigate the association of the functional monocyte chemotactic protein-1 (MCP-1) promoter polymorphism (A-2518G) with spontaneous bacterial peritonitis (SBP).
Inflammatory bowel disease(IBD)is a chronic inflammatory illness of the intes-tine.While the mechanism underlying the pathogenesis of IBD is not fully under-stood,it is believed that a complex combination of host immu...Inflammatory bowel disease(IBD)is a chronic inflammatory illness of the intes-tine.While the mechanism underlying the pathogenesis of IBD is not fully under-stood,it is believed that a complex combination of host immunological response,environmental exposure,particularly the gut microbiota,and genetic suscept-ibility represents the major determinants.The gut virome is a group of viruses found in great frequency in the gastrointestinal tract of humans.The gut virome varies greatly among individuals and is influenced by factors including lifestyle,diet,health and disease conditions,geography,and urbanization.The majority of research has focused on the significance of gut bacteria in the progression of IBD,although viral populations represent an important component of the microbiome.We conducted this review to highlight the viral communities in the gut and their expected roles in the etiopathogenesis of IBD regarding published research to date.展开更多
To enhance the understanding about the utilization of steel slags as a cementitious material, we comparatively studied the chemical, mineralogical and morphological properties of two types of steel slag; basicoxygen-f...To enhance the understanding about the utilization of steel slags as a cementitious material, we comparatively studied the chemical, mineralogical and morphological properties of two types of steel slag; basicoxygen-furnace carbon slag(BOF C) and electric-arc-furnace stainless steel slag(EAF S). Moreover, we studied the standard consistency, setting time and the effect of the slag replacement ratios on the fluidity and compressive strength of blended cement mortar. The experimental results showed that BOF C had higher alkalinity, higher pH value and more hydraulic phases than EAF S. Both types of slag showed water reduction effect due to its high fineness. Neat BOF C paste showed flash set and acceleration in the initial setting time of blended cement especially at high slag proportions. However, EAF S prolonged the setting time of blended cement even at low slag proportions. The pH values for blended cement contained 50% BOF C or EAF S were lower than those of pure cement paste. Despite of slag type, compressive strength gradually decreased with increasing slags content. The strength of BOF C mortar was higher than that of EAF S mortar with the same replacement ratio for the same age. Slag activity index demonstrated that BOF C and EAF S conformed to the Chinese National Standard(GB/T 20491-2006) requirements for steel slag as grade one and grade two, respectively.展开更多
Currently, there is a growing belief that putting an IEEE 802.11-like radio into road vehicles can help the drivers to travel more safely. Message dissemination protocols are primordial for safety vehicular applicatio...Currently, there is a growing belief that putting an IEEE 802.11-like radio into road vehicles can help the drivers to travel more safely. Message dissemination protocols are primordial for safety vehicular applications. There are two types of safety messages which may be exchanged between vehicles: alarm and beacon. In this paper we investigate the feasibility of deploying safety applications based on beacon message dissemination through extensive simulation study and pay special attention to the safety requirements. Vehicles are supposed to issue these messages periodically to announce to other vehicles their current situation and use received messages for preventing possible unsafe situations. We evaluate the performance of a single-hop dissemination protocol while taking into account the quality of service (QoS) metrics like delivery rate and delay. We realize that reliability is the main concern in beacon message dissemination. Thus, a new metric named effective range is defined which gives us more accurate facility for evaluating QoS in safety applications specifically. Then, in order to improve the performance, the effects of three parameters including vehicle's transmission range, message transmission's interval time and message payload size are studied. Due to special characteristics of the safety applications, we model the relationship between communication-level QoS and application-level QoS and evaluate them for different classes of safety applications. As a conclusion, the current technology of IEEE 802.11 MAC layer has still some challenges for automatic safety applications but it can provide acceptable QoS to driver assistance safety applications.展开更多
Three tridentate imine ligands containing N2S donors were synthesized via Schiff condensation between derivatives of both amino triazine and 2-carbonyl pyridine.The reaction of these ligands with CuCl2 in a molar rati...Three tridentate imine ligands containing N2S donors were synthesized via Schiff condensation between derivatives of both amino triazine and 2-carbonyl pyridine.The reaction of these ligands with CuCl2 in a molar ratio of 1:1 provides three Cu(II) complexes with the general formula [CuLn·Cl_(2)].Analytical,electrical,magnetic,and spectroscopic studies were used to assign the molecular formulae of these metallic chelates.Density function theory (DFT) calculations confirmed the structural analysis results obtained from spectroscopic studies.The various characterization techniques used demonstrated the penta-coordinated slightly distorted square pyramidal structure for the present Cu(II) complexes 1,2,and 3.Measurements of cyclic voltammetry were done in methanol to define the electrochemical behavior of the current Cu(II) complexes.The biomimetics of catechol oxidase (C.O.);phenoxazinone synthase (PHS) have been studied in the aerobic oxidation of some phenolic substrates,such as 3,5-di-tert-butylcatechol (3,5-DTBCH2);ortho-aminophenol (o-APH3).The three candidate oxidase mimetics showed promising activity in the order 3 > 1 > 2.The catalytic activity related to the structural properties of existing oxidase mimetics was discussed.The driving force (-ΔG°) controlling the redox reactions of the present biomolecules was calculated from the redox data of Cu(II) complexes 1,2,and 3.The potential catalytic reaction pathway for the oxidation of the studied phenolic substrates was discussed.展开更多
The Message Passing Interface (MPI) is a widely accepted standard for parallel computing on distributed memorysystems.However, MPI implementations can contain defects that impact the reliability and performance of par...The Message Passing Interface (MPI) is a widely accepted standard for parallel computing on distributed memorysystems.However, MPI implementations can contain defects that impact the reliability and performance of parallelapplications. Detecting and correcting these defects is crucial, yet there is a lack of published models specificallydesigned for correctingMPI defects. To address this, we propose a model for detecting and correcting MPI defects(DC_MPI), which aims to detect and correct defects in various types of MPI communication, including blockingpoint-to-point (BPTP), nonblocking point-to-point (NBPTP), and collective communication (CC). The defectsaddressed by the DC_MPI model include illegal MPI calls, deadlocks (DL), race conditions (RC), and messagemismatches (MM). To assess the effectiveness of the DC_MPI model, we performed experiments on a datasetconsisting of 40 MPI codes. The results indicate that the model achieved a detection rate of 37 out of 40 codes,resulting in an overall detection accuracy of 92.5%. Additionally, the execution duration of the DC_MPI modelranged from 0.81 to 1.36 s. These findings show that the DC_MPI model is useful in detecting and correctingdefects in MPI implementations, thereby enhancing the reliability and performance of parallel applications. TheDC_MPImodel fills an important research gap and provides a valuable tool for improving the quality ofMPI-basedparallel computing systems.展开更多
The effect of iron addition on the microstructure, mechanical and magnetic properties of Al-matrix composite was studied. Mechanical mixing was used for the preparation of 0, 5%, 10% and 15% Fe-Al composites（mass fra...The effect of iron addition on the microstructure, mechanical and magnetic properties of Al-matrix composite was studied. Mechanical mixing was used for the preparation of 0, 5%, 10% and 15% Fe-Al composites（mass fraction）. Mixtures of Al-Fe were compacted and sintered in a vacuum furnace at 600 °C for 1 h. X-ray diffraction（XRD） of the samples containing 5% and 10% Fe indicates the presence of Al and Fe peaks, while sample containing 15% Fe reveals Al and Al13Fe4 peaks. The results show that both densification and thermal conductivity of the composites decrease by increasing the iron content. The presence of iron in the composite improves the compressive strength and the hardness. The strengthening mechanism is associated with the grain refinement of the matrix and uniform distribution of the Fe particles, as well as the formation of Al13Fe4 intermetallic. The measured magnetization values are equal to 0.3816×10-3 A·m2/g for 5% Fe sample and increases up to 0.6597×10-3 A·m2/g for 10% Fe sample, then decreases to 0.0702×10-3 A·m2/g for 15% Fe sample. This can be explained by the formation of the diamagnetic Al13Fe4 intermetallic compound in the higher Fe content sample detected by XRD analysis.展开更多
Understanding the origins of potential source rocks and unraveling the intricate connections between reservoir oils and their source formations in the Siwa Basin(Western Desert,Egypt)necessitate a thorough oil-source ...Understanding the origins of potential source rocks and unraveling the intricate connections between reservoir oils and their source formations in the Siwa Basin(Western Desert,Egypt)necessitate a thorough oil-source correlation investigation.This objective is achieved through a meticulous analysis of well-log responses,Rock-Eval pyrolysis,and biomarker data.The analysis of Total Organic Carbon across 31 samples representing Paleozoic formations in the Siwa A-1X well reveals a spectrum of organic richness ranging from 0.17 wt%to 2.04 wt%,thereby highlighting diverse levels of organic content and the presence of both Type II and Type III kerogen.Examination of the fingerprint characteristics of eight samples from the well suggests that the Dhiffah Formation comprises a blend of terrestrial and marine organic matter.Notably,a significant contribution from more oxidized residual organic matter and gas-prone Type III kerogen is observed.Contrarily,the Desouky and Zeitoun formations exhibit mixed organic matter indicative of a transitional environment,and thus featuring a pronounced marine influence within a more reducing setting,which is associated with Type II kerogen.Through analysis of five oil samples from different wells—SIWA L-1X,SIWA R-3X,SIWA D-1X,PTAH 5X,and PTAH 6X,it is evident that terrestrial organic matter,augmented by considerable marine input,was deposited in an oxidizing environment,and contains Type III kerogen.Geochemical scrutiny confirms the coexistence of mixed terrestrial organic matter within varying redox environments.Noteworthy is the uniformity of identified kerogen Types II and III across all samples,known to have potential for hydrocarbon generation.The discovery presented in this paper unveils captivating prospects concerning the genesis of oil in the Jurassic Safa reservoir,suggesting potential links to Paleozoic sources or even originating from the Safa Member itself.These revelations mark a substantial advancement in understanding source rock dynamics and their intricate relationshi展开更多
This research uses both three-dimensional(3D)modeling and geologic well control to piece back together the architectural parts of the Late Cretaceous formations.The goal is to figure out the sizes,directions,locations...This research uses both three-dimensional(3D)modeling and geologic well control to piece back together the architectural parts of the Late Cretaceous formations.The goal is to figure out the sizes,directions,locations,and controls of the layers of the fluvial sandstone reservoirs.Sequence stratigraphy is essential for 3D reservoir modeling and petroleum geology understanding in the Bahga oilfield.The purpose of this work is to create a static model that shows the layers and facies distribution in the reservoir interval.We will use data from nine well logs and 22 seismic lines calibrated by the Abu Roash G Member reservoir core intervals to accomplish this.The petrophysical study discovered three parts in the Abu Roash G Member reservoir rock:channel fill that is affected by tides,channel fill that is dominated by tides(intertidal sands),and channel top with lenticular bedded sandstone.The model's findings point to the existence of an NNW-oriented sand body,which could be a prime location to produce hydrocarbons.The original oil in place(OOIP)is about 3,438,279 Stock Tank Barrels(STB),and the oil reserve reaches up to 1,031,484(STB).Sequence stratigraphic analysis using seismic and well log information(SB)reveals that the Upper Cretaceous AR/G reservoir of the Bahga field is characterized by third-and fourth-order stratigraphic sequences,which are constrained by three Maximum Flooding Surfaces(MFS)and two Sequence Boundaries.The integration of the derived geological model and sequence stratigraphic results can lower future extraction risk by identifying the locations and trends of the geologic facies with the necessary petrophysical properties for the hydrocarbon accumulations.展开更多
This paper validates the optimal operation for a grid-connected double-fed induction generator(DFIG)in an oscillating water column power plant(OWCPP).This study presents a novel optimization technique called the circu...This paper validates the optimal operation for a grid-connected double-fed induction generator(DFIG)in an oscillating water column power plant(OWCPP).This study presents a novel optimization technique called the circulatory system-based optimization(CSBO)approach to develop six adaptive fuzzy logic controllers(AFLCs)with 30 parameters and compare them to chaotic-billiards optimization(C-BO)and genetic algorithm(GA).The proposed controller is also compared with a proportional-integral differential(PID)controller based on a self-adaptive global-best harmony search(SGHS).CSBO-based AFLCs are fully investigated under different scenarios and experimented with using a real-time interface DSP1104.The results of using CSBO-AFLCs revealed a fast time response,fast convergence,less overshoot and minimal error compared with those achieved with C-BO-AFLC,SGHS-PID and GA-AFLC during different case studies.The CSBO-based AFLCs ensure maximum power from the DFIG in an OWCPP and enhance dynamic response with very low errors.The results show that the CSBO shows better power tracking by 25%as compared with C-BO,by 45%when compared with the GA and by 56%when compared with PID.Moreover,the integral absolute errors of six controllers are investigated to demonstrate the feasibility of CSBO-AFLC.The root mean square of the errors of six controllers using CSBO is improved by 68.27%when compared with GA,by 22.57%when compared with C-BO and by 38.42%when compared with PID.These indicators demonstrate the feasibility of CSBO when compared with other algorithms with the same OWCPP.展开更多
Hepatocellular carcinoma(HCC) is a primary liver cancer, which is one of the most prevalent cancers among humans. Many factors are involved in the liver carcinogenesis as lifestyle and environmental factors. Hepatitis...Hepatocellular carcinoma(HCC) is a primary liver cancer, which is one of the most prevalent cancers among humans. Many factors are involved in the liver carcinogenesis as lifestyle and environmental factors. Hepatitis virus infections are now recognized as the chief etiology of HCC; however, the precise mechanism is still enigmatic till now. The inflammation triggered by the cytokine-mediated immune response, was reported to be the closest factor of HCC development. Cytokines are immunoregulatory proteins produced by immune cells, functioning as orchestrators of the immune response. Genes of cytokines and their receptors are known to be polymorphic, which give rise to variations in their genes. These variations have a great impact on the expression levels of the secreted cytokines. Therefore, cytokine gene polymorphisms are involved in the molecular mechanisms of several diseases. This piece of work aims to shed much light on the role of cytokine gene polymorphisms as genetic host factor in hepatitis related HCC.展开更多
The effect of variable viscosity and thermal conductivity on steady magnetohydrodynamic（MHD） heat and mass transfer flow of viscous and incompressible fluid near a stagnation point towards a permeable stretching she...The effect of variable viscosity and thermal conductivity on steady magnetohydrodynamic（MHD） heat and mass transfer flow of viscous and incompressible fluid near a stagnation point towards a permeable stretching sheet embedded in a porous medium are presented,taking into account thermal radiation and internal heat genberation/absorbtion.The stretching velocity and the ambient fluid velocity are assumed to vary linearly with the distance from the stagnation point.The Rosseland approximation is used to describe the radiative heat flux in the energy equation.The governing fundamental equations are first transformed into a system of ordinary differential equations using a scaling group of transformations and are solved numerically by using the fourth-order Rung-Kutta method with the shooting technique.A comparison with previously published work has been carried out and the results are found to be in good agreement.The results are analyzed for the effect of different physical parameters,such as the variable viscosity and thermal conductivity,the ratio of free stream velocity to stretching velocity,the magnetic field,the porosity,the radiation and suction/injection on the flow,and the heat and mass transfer characteristics.The results indicate that the inclusion of variable viscosity and thermal conductivity into the fluids of light and medium molecular weight is able to change the boundary-layer behavior for all values of the velocity ratio parameter λ except for λ = 1.In addition,the imposition of fluid suction increases both the rate of heat and mass transfer,whereas fluid injection shows the opposite effect.展开更多
This study investigates the influence of different curing regimes on the microstructure and macro properties of ultra-high performance fiber reinforced cementitious composite （UHPFRCC）, and aims to discover whether ...This study investigates the influence of different curing regimes on the microstructure and macro properties of ultra-high performance fiber reinforced cementitious composite （UHPFRCC）, and aims to discover whether it is possible to produce qualified UHPFRCC using different curing regimes. A control mix of UHPFRCC is prepared. The mechanical performance and the short-term durability of the UHPFRCC matrix under three curing regimes are studied. In addition, the microstructures of the UHPFRCC matrix with different curing conditions are analyzed by combining scanning electron microscopy （SEM） and mercury intrusion porosimetry （MIP）. The results explore how different UHPFRCC curing regimes affect its microstructure and how the microstructure affects its macro behavior. Heat and steam curing for 3 d is succeeded to produce the UHPFRCC with nearly the same mechanical properties and durability as those of the 90 d standard curing. However, the heat cured UHPFRCC does not show great resistance to chloride-ion penetration.展开更多
Background:No standard monsplasty technique has existed until now.Although various monsplasty methods have been described,they exhibit high complication rates with sparse postoperative data.Studies that used pubic sus...Background:No standard monsplasty technique has existed until now.Although various monsplasty methods have been described,they exhibit high complication rates with sparse postoperative data.Studies that used pubic suspension techniques did not describe exact anatomical landmarks for the mons pexy.This study aimed to improve the aesthetic and functional appearance of the pubic region with long-term results for all grades of pubic ptosis or bulging with abdominoplasty and provide exact anatomical points to anchor the mons to the rectus sheath.Methods:This non-randomized prospective clinical trial included 30 patients with various degrees of abdominal wall laxity between December 2017 and September 2019.The surgical procedure was performed for female patients with pendulous abdomen,pubic ptosis or bulging,body mass index≤35 kg/m^(2),and age 18–60 years.All patients were followed for up to one year;patient satisfaction was assessed before and after surgery regarding aesthetic results and impact on outfits,hygiene,and sexual activity.Results:The marginal homogeneity test revealed a statistically significant patient satisfaction rate regarding outfits,sexual function,hygiene,and aesthetics.Regarding postoperative complications,seroma(one case)was managed by aspiration,and one case of wound dehiscence was managed conservatively with dressings.Conclusion:This study recommends a quick and reproducible monsplasty technique with a low complication rate,a technique that helps determine specific anatomical landmarks for anchoring the mons to the rectus sheath.Combining this technique with abdominal contouring is advisable for optimal aesthetic results and maintained lymphatic drainage in the pubic region.展开更多
Objectives: Hypertension is a major risk factor for several cardiovascular diseases, including stroke, atherosclerosis and coronary heart disease. Remodeling of the aortic root may be expected to occur in hypertensive...Objectives: Hypertension is a major risk factor for several cardiovascular diseases, including stroke, atherosclerosis and coronary heart disease. Remodeling of the aortic root may be expected to occur in hypertensive subjects as a result of increased stress on the aortic wall due to the repeated hemodynamic overload. Two-dimensional speckle tracking echocardiography is a promising new imaging modality. The aim of this study is to assess aortic root mechanics in relation to left ventricular mechanics in hypertensive patients by speckle tracking echocardiography. Methods: The study included 50 individuals, 30 patients with hypertension compared with 20 age and sex matched healthy volunteers as control group. For both groups, conventional echo was done and speckle tracking echocardiography of the LV including longitudinal, circumferential, radial strain, LV rotation and the longitudinal strain of the ascending aorta and aortic distensibility were measured. Results: Aortic longitudinal strain of both anterior and posterior walls, andalso LV longitudinal peak systolic strain were lower significantly in patient group, and also in the same group, the apical rotation was higher than control;aortic longitudinal strain was negatively correlated with E/E, and LV global longitudinal strain was correlated positively with septal annular E wave peak velocity and with aortic distensibility. Conclusion: Hypertension significantly lowers ascending aortic longitudinal strain and the changes are correlated significantly with LV longitudinal systolic function and with echo parameters of elevated LV filling pressure.展开更多
The solar chimney power plant is a relatively new electricity generation concept, based on renewable energy, combining the greenhouse effect with the chimney suction. The solar chimney powerplant consists of three par...The solar chimney power plant is a relatively new electricity generation concept, based on renewable energy, combining the greenhouse effect with the chimney suction. The solar chimney powerplant consists of three parts, the solar collector, the chimney and the turbine generator unit, of which the study was focused on the later part. To evaluate the turbine performance inside the solar chimney powerplant, experimental system was constructed in Aswan, Egypt that has a metrological site (23°58'N and 32°47'E) occurs. The system was constructed to evaluate the performance of the solar chimney turbine and power generation characteristic in the hottest site where Aswan is located at the nearest of the Tropic of Cancer at the summer season. Velocity, electric power generation and the turbine efficiency are studying in this work. The numerical analyses were performed by using a commercial code CFX, ANSYS 16.1 to simulate the flow through the turbine and overall system. The study shows that the range of power generated (1.2 W - 4.4 W). It can be estimated, according to the results, the variation trend in pressure drops with the turbine rotation speed increase with small differences when the turbine rotation speed surpasses 1800 rpm with average efficiency of 57%. It is concluded that the theoretical model is basically valid for the system under study, and the CFD simulation can be used conveniently to predict the performance of the system, the comparison between them and experimental result shows a good agreement.展开更多
文摘AIM To evaluate the evolution, trends in surgical approaches a n d r e c o n s t r u c t i o n t e c h n i q u e s, a n d i m p o r t a n t lessons learned from performing 1000 consecutive pancreaticoduodenectomies(PDs) for periampullary tumors.METHODS This is a retrospective review of the data of all patients who underwent PD for periampullary tumor during the period from January 1993 to April 2017. The data were categorized into three periods, including early period(1993-2002), middle period(2003-2012), and late period(2013-2017).RESULTS The frequency showed PD was increasingly performed after the year 2000. With time, elderly, cirrhotic and obese patients, as well as patients with uncinate process carcinoma and borderline tumor were increasingly selected for PD. The median operative time and postoperative hospital stay decreased significantly over the periods. Hospital mortality declined significantly, from 6.6% to 3.1%. Postoperative complications significantly decreased, from 40% to 27.9%. There was significant decrease in postoperative pancreatic fistula in the second 10 years, from 15% to 12.7%. There was a significant improvement in median survival and overall survival among the periods.CONCLUSION Surgical results of PD significantly improved, with mortality rate nearly reaching 3%. Pancreatic reconstruction following PD is still debatable. The survival rate was also improved but the rate of recurrence is still high, at 36.9%.
文摘AIM:To evaluate effective alternative antibiotics in treatment of cefotaxime-resistant spontaneous bacterial peritonitis.METHODS:One hundred cirrhotic patients with spontaneous bacterial peritonitis [ascitic fluid polymorphonuclear cell count(PMNLs) ≥ 250 cells/mm 3 at admission] were empirically treated with cefotaxime sodium 2 g/12 h and volume expansion by intravenous human albumin.All patients were subjected to history taking,complete examination,laboratory tests(including a complete blood cell count,prothrombin time,biochemical tests of liver and kidney function,and fresh urine sediment),chest X-ray,a diagnostic abdominal paracentesis,and the sample subjected to total and differential cell count,chemical examination,aerobic and anaerobic cultures.Patients were divided after 2 d by a second ascitic PMNL count into group Ⅰ;patients sensitive to cefotaxime(n = 81),group Ⅱ(n = 19);cases resistant to cefotaxime(less than 25% decrease in ascitic PMNL count).Patients of group Ⅱ were randomly assigned into meropenem(n = 11) or levofloxacin(n = 8) subgroups.All patients performed an end of treatment ascitic PMNL count.Patients were considered improved when:PMNLs decreased to < 250 cells/mm 3,no growth in previously positive culture cases,and improved clinical manifestations with at least 5 d of antibiotic therapy.RESULTS:Age,sex,and Child classes showed no significant difference between group Ⅰ and group Ⅱ.Fever and abdominal pain were the most frequent manifestations and were reported in 82.7% and 80.2% of patients in group Ⅰ and in 94.7% and 84.2% of patients in group Ⅱ,respectively.Patients in group Ⅱ had a more severe ascitic inflammatory response than group Ⅰ and this was demonstrated by more ascitic lactate dehydrogenase(LDH) [median:540 IU/L(range:150-1200 IU/L) vs median:240 IU/L(range:180-500 IU/L),P = 0.000] and PMNL [median:15 000 cell/mm 3(range:957-23 822 cell/mm 3) vs 3400 cell/mm 3(range:695-26 400 cell/mm 3),P = 0.000] counts.Ascitic fluid culture was positive in 32% of cases.Cefot
基金Supported in part by Natural Sciences and Engineering Research Council of Canada(NSERC)eMech Systems IncBare Point Water Treatment Plant in Thunder Bay,Ontario,Canada
文摘Induction motors （IMs） are commonly used in various industrial applications. To improve energy con- sumption efficiency, a reliable IM health condition moni- toring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is pro- posed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are syn- thesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air- gap eccentricity diagnosis. The effectiveness of the pro- posed harmonic synthesis technique is examined experi- mentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.
文摘AIM:To analyze cases of obstruction of the nasolacrimal duct which creates a fertile environment for secondary bacterial Infection and can result in dacryocystitis,which is a constant threat to cornea and orbital soft tissue and a potential source of endophthalmitis following intraocular surgery.The majority of obstructions of the lacrimal excretory outflow system are acquired ones occurring in adulthood and involving the distal parts of the system.Acquired obstruction may be primary/idiopathic or secondary to a wide variety of infectious,inflammatory,traumatic,mechanical,toxic or neoplastic causes mimicking idiopathic inflammation.These cases are treated by dacryocystorhinostomy(DCR).METHODS:The present study was conducted to determine the histopathologic,immunohistochemical and current microbiologic characteristics of lacrimal sac specimens in patients undergoing external dacryocystorhinostomy.RESULTS:Non-specific lacrimal sac pathology was present in all 33 cases and 81.8%of the cases showed moderate chronic inflammation with a chronic inflammatory score(CIS)ranging between 4 and 6,whereas 12.12%showed severe inflammatory changes with a CIS of 7.Mild degree of inflammation was seen in6.06%with a CIS of 3.The total prevalence of grampositive,gram-negative,and culture-negative samples were 59.4%,37.5%,and 3%respectively.CONCLUSION:Non-specific chronic inflammation withfibrosis is indeed the most commonly reported histopathological finding in lacrimal sac wall biopsy specimens.
文摘AIM: To investigate the association of the functional monocyte chemotactic protein-1 (MCP-1) promoter polymorphism (A-2518G) with spontaneous bacterial peritonitis (SBP).
文摘Inflammatory bowel disease(IBD)is a chronic inflammatory illness of the intes-tine.While the mechanism underlying the pathogenesis of IBD is not fully under-stood,it is believed that a complex combination of host immunological response,environmental exposure,particularly the gut microbiota,and genetic suscept-ibility represents the major determinants.The gut virome is a group of viruses found in great frequency in the gastrointestinal tract of humans.The gut virome varies greatly among individuals and is influenced by factors including lifestyle,diet,health and disease conditions,geography,and urbanization.The majority of research has focused on the significance of gut bacteria in the progression of IBD,although viral populations represent an important component of the microbiome.We conducted this review to highlight the viral communities in the gut and their expected roles in the etiopathogenesis of IBD regarding published research to date.
基金Funded by the National Natural Science Foundations of China(Nos.51378113 and 51438003)the Plan of Six Peak Talents in Jiangsu Province(No.JZ-004)Partly Supported by the National Basic Research Program of China(973 Program,No.2015CB655102)
文摘To enhance the understanding about the utilization of steel slags as a cementitious material, we comparatively studied the chemical, mineralogical and morphological properties of two types of steel slag; basicoxygen-furnace carbon slag(BOF C) and electric-arc-furnace stainless steel slag(EAF S). Moreover, we studied the standard consistency, setting time and the effect of the slag replacement ratios on the fluidity and compressive strength of blended cement mortar. The experimental results showed that BOF C had higher alkalinity, higher pH value and more hydraulic phases than EAF S. Both types of slag showed water reduction effect due to its high fineness. Neat BOF C paste showed flash set and acceleration in the initial setting time of blended cement especially at high slag proportions. However, EAF S prolonged the setting time of blended cement even at low slag proportions. The pH values for blended cement contained 50% BOF C or EAF S were lower than those of pure cement paste. Despite of slag type, compressive strength gradually decreased with increasing slags content. The strength of BOF C mortar was higher than that of EAF S mortar with the same replacement ratio for the same age. Slag activity index demonstrated that BOF C and EAF S conformed to the Chinese National Standard(GB/T 20491-2006) requirements for steel slag as grade one and grade two, respectively.
基金the Iran Telecommunication Research Center (ITRC)
文摘Currently, there is a growing belief that putting an IEEE 802.11-like radio into road vehicles can help the drivers to travel more safely. Message dissemination protocols are primordial for safety vehicular applications. There are two types of safety messages which may be exchanged between vehicles: alarm and beacon. In this paper we investigate the feasibility of deploying safety applications based on beacon message dissemination through extensive simulation study and pay special attention to the safety requirements. Vehicles are supposed to issue these messages periodically to announce to other vehicles their current situation and use received messages for preventing possible unsafe situations. We evaluate the performance of a single-hop dissemination protocol while taking into account the quality of service (QoS) metrics like delivery rate and delay. We realize that reliability is the main concern in beacon message dissemination. Thus, a new metric named effective range is defined which gives us more accurate facility for evaluating QoS in safety applications specifically. Then, in order to improve the performance, the effects of three parameters including vehicle's transmission range, message transmission's interval time and message payload size are studied. Due to special characteristics of the safety applications, we model the relationship between communication-level QoS and application-level QoS and evaluate them for different classes of safety applications. As a conclusion, the current technology of IEEE 802.11 MAC layer has still some challenges for automatic safety applications but it can provide acceptable QoS to driver assistance safety applications.
基金the Deanship of Graduate Studies and Scientific Research,Taif University for funding this work.
文摘Three tridentate imine ligands containing N2S donors were synthesized via Schiff condensation between derivatives of both amino triazine and 2-carbonyl pyridine.The reaction of these ligands with CuCl2 in a molar ratio of 1:1 provides three Cu(II) complexes with the general formula [CuLn·Cl_(2)].Analytical,electrical,magnetic,and spectroscopic studies were used to assign the molecular formulae of these metallic chelates.Density function theory (DFT) calculations confirmed the structural analysis results obtained from spectroscopic studies.The various characterization techniques used demonstrated the penta-coordinated slightly distorted square pyramidal structure for the present Cu(II) complexes 1,2,and 3.Measurements of cyclic voltammetry were done in methanol to define the electrochemical behavior of the current Cu(II) complexes.The biomimetics of catechol oxidase (C.O.);phenoxazinone synthase (PHS) have been studied in the aerobic oxidation of some phenolic substrates,such as 3,5-di-tert-butylcatechol (3,5-DTBCH2);ortho-aminophenol (o-APH3).The three candidate oxidase mimetics showed promising activity in the order 3 > 1 > 2.The catalytic activity related to the structural properties of existing oxidase mimetics was discussed.The driving force (-ΔG°) controlling the redox reactions of the present biomolecules was calculated from the redox data of Cu(II) complexes 1,2,and 3.The potential catalytic reaction pathway for the oxidation of the studied phenolic substrates was discussed.
基金the Deanship of Scientific Research at King Abdulaziz University,Jeddah,Saudi Arabia under the Grant No.RG-12-611-43.
文摘The Message Passing Interface (MPI) is a widely accepted standard for parallel computing on distributed memorysystems.However, MPI implementations can contain defects that impact the reliability and performance of parallelapplications. Detecting and correcting these defects is crucial, yet there is a lack of published models specificallydesigned for correctingMPI defects. To address this, we propose a model for detecting and correcting MPI defects(DC_MPI), which aims to detect and correct defects in various types of MPI communication, including blockingpoint-to-point (BPTP), nonblocking point-to-point (NBPTP), and collective communication (CC). The defectsaddressed by the DC_MPI model include illegal MPI calls, deadlocks (DL), race conditions (RC), and messagemismatches (MM). To assess the effectiveness of the DC_MPI model, we performed experiments on a datasetconsisting of 40 MPI codes. The results indicate that the model achieved a detection rate of 37 out of 40 codes,resulting in an overall detection accuracy of 92.5%. Additionally, the execution duration of the DC_MPI modelranged from 0.81 to 1.36 s. These findings show that the DC_MPI model is useful in detecting and correctingdefects in MPI implementations, thereby enhancing the reliability and performance of parallel applications. TheDC_MPImodel fills an important research gap and provides a valuable tool for improving the quality ofMPI-basedparallel computing systems.
文摘The effect of iron addition on the microstructure, mechanical and magnetic properties of Al-matrix composite was studied. Mechanical mixing was used for the preparation of 0, 5%, 10% and 15% Fe-Al composites（mass fraction）. Mixtures of Al-Fe were compacted and sintered in a vacuum furnace at 600 °C for 1 h. X-ray diffraction（XRD） of the samples containing 5% and 10% Fe indicates the presence of Al and Fe peaks, while sample containing 15% Fe reveals Al and Al13Fe4 peaks. The results show that both densification and thermal conductivity of the composites decrease by increasing the iron content. The presence of iron in the composite improves the compressive strength and the hardness. The strengthening mechanism is associated with the grain refinement of the matrix and uniform distribution of the Fe particles, as well as the formation of Al13Fe4 intermetallic. The measured magnetization values are equal to 0.3816×10-3 A·m2/g for 5% Fe sample and increases up to 0.6597×10-3 A·m2/g for 10% Fe sample, then decreases to 0.0702×10-3 A·m2/g for 15% Fe sample. This can be explained by the formation of the diamagnetic Al13Fe4 intermetallic compound in the higher Fe content sample detected by XRD analysis.
基金the research project is funded by Abdullah Alrushaid Chair for Earth Science Remote Sensing Research at King Saud University,Riyadh,Saudi Arabia.。
文摘Understanding the origins of potential source rocks and unraveling the intricate connections between reservoir oils and their source formations in the Siwa Basin(Western Desert,Egypt)necessitate a thorough oil-source correlation investigation.This objective is achieved through a meticulous analysis of well-log responses,Rock-Eval pyrolysis,and biomarker data.The analysis of Total Organic Carbon across 31 samples representing Paleozoic formations in the Siwa A-1X well reveals a spectrum of organic richness ranging from 0.17 wt%to 2.04 wt%,thereby highlighting diverse levels of organic content and the presence of both Type II and Type III kerogen.Examination of the fingerprint characteristics of eight samples from the well suggests that the Dhiffah Formation comprises a blend of terrestrial and marine organic matter.Notably,a significant contribution from more oxidized residual organic matter and gas-prone Type III kerogen is observed.Contrarily,the Desouky and Zeitoun formations exhibit mixed organic matter indicative of a transitional environment,and thus featuring a pronounced marine influence within a more reducing setting,which is associated with Type II kerogen.Through analysis of five oil samples from different wells—SIWA L-1X,SIWA R-3X,SIWA D-1X,PTAH 5X,and PTAH 6X,it is evident that terrestrial organic matter,augmented by considerable marine input,was deposited in an oxidizing environment,and contains Type III kerogen.Geochemical scrutiny confirms the coexistence of mixed terrestrial organic matter within varying redox environments.Noteworthy is the uniformity of identified kerogen Types II and III across all samples,known to have potential for hydrocarbon generation.The discovery presented in this paper unveils captivating prospects concerning the genesis of oil in the Jurassic Safa reservoir,suggesting potential links to Paleozoic sources or even originating from the Safa Member itself.These revelations mark a substantial advancement in understanding source rock dynamics and their intricate relationshi
文摘This research uses both three-dimensional(3D)modeling and geologic well control to piece back together the architectural parts of the Late Cretaceous formations.The goal is to figure out the sizes,directions,locations,and controls of the layers of the fluvial sandstone reservoirs.Sequence stratigraphy is essential for 3D reservoir modeling and petroleum geology understanding in the Bahga oilfield.The purpose of this work is to create a static model that shows the layers and facies distribution in the reservoir interval.We will use data from nine well logs and 22 seismic lines calibrated by the Abu Roash G Member reservoir core intervals to accomplish this.The petrophysical study discovered three parts in the Abu Roash G Member reservoir rock:channel fill that is affected by tides,channel fill that is dominated by tides(intertidal sands),and channel top with lenticular bedded sandstone.The model's findings point to the existence of an NNW-oriented sand body,which could be a prime location to produce hydrocarbons.The original oil in place(OOIP)is about 3,438,279 Stock Tank Barrels(STB),and the oil reserve reaches up to 1,031,484(STB).Sequence stratigraphic analysis using seismic and well log information(SB)reveals that the Upper Cretaceous AR/G reservoir of the Bahga field is characterized by third-and fourth-order stratigraphic sequences,which are constrained by three Maximum Flooding Surfaces(MFS)and two Sequence Boundaries.The integration of the derived geological model and sequence stratigraphic results can lower future extraction risk by identifying the locations and trends of the geologic facies with the necessary petrophysical properties for the hydrocarbon accumulations.
文摘This paper validates the optimal operation for a grid-connected double-fed induction generator(DFIG)in an oscillating water column power plant(OWCPP).This study presents a novel optimization technique called the circulatory system-based optimization(CSBO)approach to develop six adaptive fuzzy logic controllers(AFLCs)with 30 parameters and compare them to chaotic-billiards optimization(C-BO)and genetic algorithm(GA).The proposed controller is also compared with a proportional-integral differential(PID)controller based on a self-adaptive global-best harmony search(SGHS).CSBO-based AFLCs are fully investigated under different scenarios and experimented with using a real-time interface DSP1104.The results of using CSBO-AFLCs revealed a fast time response,fast convergence,less overshoot and minimal error compared with those achieved with C-BO-AFLC,SGHS-PID and GA-AFLC during different case studies.The CSBO-based AFLCs ensure maximum power from the DFIG in an OWCPP and enhance dynamic response with very low errors.The results show that the CSBO shows better power tracking by 25%as compared with C-BO,by 45%when compared with the GA and by 56%when compared with PID.Moreover,the integral absolute errors of six controllers are investigated to demonstrate the feasibility of CSBO-AFLC.The root mean square of the errors of six controllers using CSBO is improved by 68.27%when compared with GA,by 22.57%when compared with C-BO and by 38.42%when compared with PID.These indicators demonstrate the feasibility of CSBO when compared with other algorithms with the same OWCPP.
文摘Hepatocellular carcinoma(HCC) is a primary liver cancer, which is one of the most prevalent cancers among humans. Many factors are involved in the liver carcinogenesis as lifestyle and environmental factors. Hepatitis virus infections are now recognized as the chief etiology of HCC; however, the precise mechanism is still enigmatic till now. The inflammation triggered by the cytokine-mediated immune response, was reported to be the closest factor of HCC development. Cytokines are immunoregulatory proteins produced by immune cells, functioning as orchestrators of the immune response. Genes of cytokines and their receptors are known to be polymorphic, which give rise to variations in their genes. These variations have a great impact on the expression levels of the secreted cytokines. Therefore, cytokine gene polymorphisms are involved in the molecular mechanisms of several diseases. This piece of work aims to shed much light on the role of cytokine gene polymorphisms as genetic host factor in hepatitis related HCC.
文摘The effect of variable viscosity and thermal conductivity on steady magnetohydrodynamic（MHD） heat and mass transfer flow of viscous and incompressible fluid near a stagnation point towards a permeable stretching sheet embedded in a porous medium are presented,taking into account thermal radiation and internal heat genberation/absorbtion.The stretching velocity and the ambient fluid velocity are assumed to vary linearly with the distance from the stagnation point.The Rosseland approximation is used to describe the radiative heat flux in the energy equation.The governing fundamental equations are first transformed into a system of ordinary differential equations using a scaling group of transformations and are solved numerically by using the fourth-order Rung-Kutta method with the shooting technique.A comparison with previously published work has been carried out and the results are found to be in good agreement.The results are analyzed for the effect of different physical parameters,such as the variable viscosity and thermal conductivity,the ratio of free stream velocity to stretching velocity,the magnetic field,the porosity,the radiation and suction/injection on the flow,and the heat and mass transfer characteristics.The results indicate that the inclusion of variable viscosity and thermal conductivity into the fluids of light and medium molecular weight is able to change the boundary-layer behavior for all values of the velocity ratio parameter λ except for λ = 1.In addition,the imposition of fluid suction increases both the rate of heat and mass transfer,whereas fluid injection shows the opposite effect.
基金The Scholarship Supported by the China Scholarship Councilthe Technical Research Program from NV Bekaert SA of Belgiumthe National Natural Science Foundation of China(No.50908047)
文摘This study investigates the influence of different curing regimes on the microstructure and macro properties of ultra-high performance fiber reinforced cementitious composite （UHPFRCC）, and aims to discover whether it is possible to produce qualified UHPFRCC using different curing regimes. A control mix of UHPFRCC is prepared. The mechanical performance and the short-term durability of the UHPFRCC matrix under three curing regimes are studied. In addition, the microstructures of the UHPFRCC matrix with different curing conditions are analyzed by combining scanning electron microscopy （SEM） and mercury intrusion porosimetry （MIP）. The results explore how different UHPFRCC curing regimes affect its microstructure and how the microstructure affects its macro behavior. Heat and steam curing for 3 d is succeeded to produce the UHPFRCC with nearly the same mechanical properties and durability as those of the 90 d standard curing. However, the heat cured UHPFRCC does not show great resistance to chloride-ion penetration.
文摘Background:No standard monsplasty technique has existed until now.Although various monsplasty methods have been described,they exhibit high complication rates with sparse postoperative data.Studies that used pubic suspension techniques did not describe exact anatomical landmarks for the mons pexy.This study aimed to improve the aesthetic and functional appearance of the pubic region with long-term results for all grades of pubic ptosis or bulging with abdominoplasty and provide exact anatomical points to anchor the mons to the rectus sheath.Methods:This non-randomized prospective clinical trial included 30 patients with various degrees of abdominal wall laxity between December 2017 and September 2019.The surgical procedure was performed for female patients with pendulous abdomen,pubic ptosis or bulging,body mass index≤35 kg/m^(2),and age 18–60 years.All patients were followed for up to one year;patient satisfaction was assessed before and after surgery regarding aesthetic results and impact on outfits,hygiene,and sexual activity.Results:The marginal homogeneity test revealed a statistically significant patient satisfaction rate regarding outfits,sexual function,hygiene,and aesthetics.Regarding postoperative complications,seroma(one case)was managed by aspiration,and one case of wound dehiscence was managed conservatively with dressings.Conclusion:This study recommends a quick and reproducible monsplasty technique with a low complication rate,a technique that helps determine specific anatomical landmarks for anchoring the mons to the rectus sheath.Combining this technique with abdominal contouring is advisable for optimal aesthetic results and maintained lymphatic drainage in the pubic region.
文摘Objectives: Hypertension is a major risk factor for several cardiovascular diseases, including stroke, atherosclerosis and coronary heart disease. Remodeling of the aortic root may be expected to occur in hypertensive subjects as a result of increased stress on the aortic wall due to the repeated hemodynamic overload. Two-dimensional speckle tracking echocardiography is a promising new imaging modality. The aim of this study is to assess aortic root mechanics in relation to left ventricular mechanics in hypertensive patients by speckle tracking echocardiography. Methods: The study included 50 individuals, 30 patients with hypertension compared with 20 age and sex matched healthy volunteers as control group. For both groups, conventional echo was done and speckle tracking echocardiography of the LV including longitudinal, circumferential, radial strain, LV rotation and the longitudinal strain of the ascending aorta and aortic distensibility were measured. Results: Aortic longitudinal strain of both anterior and posterior walls, andalso LV longitudinal peak systolic strain were lower significantly in patient group, and also in the same group, the apical rotation was higher than control;aortic longitudinal strain was negatively correlated with E/E, and LV global longitudinal strain was correlated positively with septal annular E wave peak velocity and with aortic distensibility. Conclusion: Hypertension significantly lowers ascending aortic longitudinal strain and the changes are correlated significantly with LV longitudinal systolic function and with echo parameters of elevated LV filling pressure.
文摘The solar chimney power plant is a relatively new electricity generation concept, based on renewable energy, combining the greenhouse effect with the chimney suction. The solar chimney powerplant consists of three parts, the solar collector, the chimney and the turbine generator unit, of which the study was focused on the later part. To evaluate the turbine performance inside the solar chimney powerplant, experimental system was constructed in Aswan, Egypt that has a metrological site (23°58'N and 32°47'E) occurs. The system was constructed to evaluate the performance of the solar chimney turbine and power generation characteristic in the hottest site where Aswan is located at the nearest of the Tropic of Cancer at the summer season. Velocity, electric power generation and the turbine efficiency are studying in this work. The numerical analyses were performed by using a commercial code CFX, ANSYS 16.1 to simulate the flow through the turbine and overall system. The study shows that the range of power generated (1.2 W - 4.4 W). It can be estimated, according to the results, the variation trend in pressure drops with the turbine rotation speed increase with small differences when the turbine rotation speed surpasses 1800 rpm with average efficiency of 57%. It is concluded that the theoretical model is basically valid for the system under study, and the CFD simulation can be used conveniently to predict the performance of the system, the comparison between them and experimental result shows a good agreement.
