1,714 research outputs found
Mathematical Modeling of Heat-Transfer for a Moving Sheet in a Moving Fluid
A mathematical model was developed for determining the heat transfer between a moving sheet that passes through a
moving fluid environment to simulate the fabrication process of sheet and fiber-like materials. Similarity
transformations were introduced to reduce the governing equations to two nonlinear ordinary differential equations.
For high values Prandtl number, the energy equation became much stiffer or singularly perturbed and the standard
numerical methods failed to handle it. An innovative procedure combining shooting and singular perturbation
technique was developed. The results show that the heat transfer depends on the relative velocity between the moving
fluid and the moving sheet to a certain value after that value the relative velocity has no effect. If blowing effect is
found the thermal layer becomes thinner and temperature profiles are backed together
On the (non-)existence of polynomial kernels for Pl-free edge modification problems
Given a graph G = (V,E) and an integer k, an edge modification problem for a
graph property P consists in deciding whether there exists a set of edges F of
size at most k such that the graph H = (V,E \vartriangle F) satisfies the
property P. In the P edge-completion problem, the set F of edges is constrained
to be disjoint from E; in the P edge-deletion problem, F is a subset of E; no
constraint is imposed on F in the P edge-edition problem. A number of
optimization problems can be expressed in terms of graph modification problems
which have been extensively studied in the context of parameterized complexity.
When parameterized by the size k of the edge set F, it has been proved that if
P is an hereditary property characterized by a finite set of forbidden induced
subgraphs, then the three P edge-modification problems are FPT. It was then
natural to ask whether these problems also admit a polynomial size kernel.
Using recent lower bound techniques, Kratsch and Wahlstrom answered this
question negatively. However, the problem remains open on many natural graph
classes characterized by forbidden induced subgraphs. Kratsch and Wahlstrom
asked whether the result holds when the forbidden subgraphs are paths or cycles
and pointed out that the problem is already open in the case of P4-free graphs
(i.e. cographs). This paper provides positive and negative results in that line
of research. We prove that parameterized cograph edge modification problems
have cubic vertex kernels whereas polynomial kernels are unlikely to exist for
the Pl-free and Cl-free edge-deletion problems for large enough l
The effect of completeness of revascularization during CABG with single versus multiple arterial grafts
IntroductionIncomplete coronary revascularization is associated with suboptimal outcomes. We investigated the longâ term effects of Incomplete, Complete, and Supraâ complete revascularization and whether these effects differed in the setting of singleâ arterial and multiâ arterial coronary artery bypass graft (CABG).MethodsWe analyzed 15â year mortality in 7157 CABG patients (64.1â ±â 10.5 years; 30% women). All patients received a left internal thoracic artery to left anterior descending coronary artery graft with additional venous grafts only (singleâ arterial) or with at least one additional arterial graft (multiâ arterial) and were grouped based on a completeness of revascularization index (CRIâ =â number of grafts minus the number of diseased principal coronary arteries): Incomplete (CRIâ â ¤â â 1 [Nâ =â 320;4.5%]); Complete (CRIâ =â 0 [Nâ =â 2882;40.3%]; reference group); and two Supraâ complete categories (CRIâ =â +1[Nâ =â 3050; 42.6%]; CRIâ â ¥â +â 2 [Nâ =â 905; 12.6%]). Riskâ adjusted mortality hazard ratios (AHR) were calculated using comprehensive propensity score adjustment by Cox regression.ResultsIncomplete revascularization was rare (4.5%) but associated with increased mortality in all patients (AHR [95% confidence interval]â =â 1.53 [1.29â 1.80]), those undergoing singleâ arterial CABG (AHRâ =â 1.27 [1.04â 1.54]) and multiâ arterial CABG (AHRâ =â 2.18 [1.60â 2.99]), as well as in patients with 3â Vessel (AHRâ =â 1.37 [1.16â 1.62]) and, to a lesser degree, with 2â Vessel (AHRâ =â 1.67 [0.53â 5.23]) coronary disease. Supraâ complete revascularization was generally associated with incrementally decreased mortality in all patients (AHR [CRIâ =â +1]â =â 0.94 [0.87â 1.03]); AHR [CRIâ â ¥â +2]â =â 0.74 [0.64â 0.85]), and was driven by a significantly decreased mortality risk in singleâ arterial CABG (AHR [CRIâ =â +1]â =â 0.90 [0.81â 0.99]; AHR [CRIâ â ¥â +2]â =â 0.64 [0.53â 0.78]); and 3â Vessel disease patients (AHR [CRIâ =â +1]â =â 0.94 [0.86â 1.04]; and AHR [CRIâ â ¥â +2]â =â 0.75 [0.63â 0.88]) with no impact in multiâ arterial CABG (AHR [CRIâ =â +1]â =â 1.07 [0.91â 1.26]; AHR [CRIâ â ¥â +2]â =â 0.93 [0.73â 1.17]).ConclusionsIncomplete revascularization is associated with decreased late survival, irrespective of grafting strategy. Alternatively, supraâ complete revascularization is associated with improved survival in patients with 3â Vessel CAD, and in singleâ arterial but not multiâ arterial CABG.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146364/1/jocs13810.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146364/2/jocs13810_am.pd
Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes
A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p
Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes
A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p
DIFFERENT TOPICAL FORMULATIONS OF KETOROLAC TROMETHAMINE FOR ANTI-INFLAMMATORY APPLICATION AND CLINICAL EFFICACY
Ketorolac tromethamine (KT) is considered as a member of NSAIDs that used in treatment of rheumatoid arthritis. The main problems associated with the frequent administration of KT orally could be overcome by alternative routes as topical application. KT was formulated in different topical formulations such as gels, emulgels and creams. Sodium carboxymethylcellulose, carbopol 934 and pluronic F127 were used as polymers. In vitro permeation study through rat skin was carried out. The effect of different KT concentrations and the effect of skin penetration enhancer on the amount of KT permeated were investigated. Anti-inflammatory activity using commercial piroxicam gel for comparison was evaluated. The effectiveness and tolerability of the selected KT gel and piroxicam gel in osteoarthritis patients was also studied. The results obtained showed that, the flux of the drug increased with increasing its initial concentration. Using sodium lauryl sulfate as enhancer resulted in an improvement of KT permeation through rat skin. All formulations had the potential for local applications of KT as anti-inflammatory drug as compared to the control group. There was no significant difference in the efficacy between the selected KT gel and piroxicam gel for osteoarthritis patients. So KT gel may be used as another therapeutic option for the treatment of patients with osteoarthritis
Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors
The development of highly-sensitive and miniaturized sensors that capable of
real-time analytes detection is highly desirable. Nowadays, toxic or colorless
gas detection, air pollution monitoring, harmful chemical, pressure, strain,
humidity, and temperature sensors based on photonic crystal fiber (PCF) are
increasing rapidly due to its compact structure, fast response and efficient
light controlling capabilities. The propagating light through the PCF can be
controlled by varying the structural parameters and core-cladding materials, as
a result, evanescent field can be enhanced significantly which is the main
component of the PCF based gas/chemical sensors. The aim of this chapter is to
(1) describe the principle operation of PCF based gas/ chemical sensors, (2)
discuss the important PCF properties for optical sensors, (3) extensively
discuss the different types of microstructured optical fiber based gas/
chemical sensors, (4) study the effects of different core-cladding shapes, and
fiber background materials on sensing performance, and (5) highlight the main
challenges of PCF based gas/ chemical sensors and possible solutions
Wheat (Triticum aestivum l.) production under drought and heat stress – adverse effects, mechanisms and mitigation: A review
Heat and drought stresses are the most important abiotic factors that reduce crops productivity by affecting various physiological and biochemical processes. Thus, selecting cultivars with better drought or heat stress tolerance or breeding for stress tolerance will be helpful in enhancing crop productivity under harsh environments. This review elaborates the physiological basis of high temperature and drought stress tolerance in wheat which can be used as selection criteria in wheat breeding program. In addition, some agronomic selection criteria which are valid and useful in selecting stress tolerant wheat species and cultivars. The review also discussed the valid usage of stress tolerance indices (such as mean productivity (MP), geometric mean productivity (GMP), yield index (YI), yield stability index (YSI), relative productivity (RP%), stress susceptibility index (SSI), and the tolerance index (TOL)) to scan the genotypes against drought and heat stress. Beside these, exogenous application of stress signaling compounds, osmolytes, or certain inorganic salts play a vital role for alleviating adverse effects of abiotic stresses for sustainable wheat production. In addition, applications for soil amendments will also helpful in increasing wheat crop productivity under stressful conditions. All these strategies may be helpful to meet the food demands of the increasing population.Fil: El Sabagh, A.. University of Kafrelsheikh; EgiptoFil: Hossain, A.. Bangladesh Agricultural Research Institute; BangladeshFil: Barutçular, C.. University of Çukurova; TurquíaFil: Islam, Mohammad Sirajul. Hajee Mohammad Danesh Science and Technology University; BangladeshFil: Awan, S. I.. University of the Poonch; PakistánFil: Galal, A.. University of Kafrelsheikh; EgiptoFil: Iqbal, M. A.. University of the Poonch; PakistánFil: Sytar, O.. Slovak University of Agriculture; EslovaquiaFil: Yildirim, M.. Dicle University; TurquíaFil: Meena, R. S.. Inistitute of Agricultural Sciences; IndiaFil: Fahad, S.. The University of Swabi; PakistánFil: Najeeb, U.. The University of Queensland; AustraliaFil: Konuskan, O.. Mustafa Kemal University; TurquíaFil: Habib, R. A.. Bahauddin Zakariya University; PakistánFil: Llanes, Analia Susana. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Hussain, S.. University of Agriculture; PakistánFil: Farooq, M.. Sultan Qaboos University; OmánFil: Hasanuzzaman, M.. Sher-e-Bangla Agricultural University; BangladeshFil: Abdelaal, K. H.. Kafrelsheikh University; EgiptoFil: Hafez, Y.. Kafrelsheikh University; EgiptoFil: Cig, F.. Siirt University; TurquíaFil: Saneoka, H.. Hiroshima University; Japó
Diabetes mellitus in Egypt: glycaemic control and microvascular and neuropathic complications
We performed a cross-sectional, population-based survey of persons 20 years of age and older living in Cairo and surrounding rural villages. The purpose was to describe glycaemic control and the prevalence of microvascular and neuropathic complications among Egyptians with diagnosed diabetes, previously undiagnosed diabetes, impaired glucose tolerance, and normal glucose tolerance. A total of 6052 households were surveyed. The response rate was 76 % for the household survey and 72 % for the medical examination. Among people with previously diagnosed diabetes, mean haemoglobin A 1c was 9.0 %. Forty-two per cent had retinopathy, 21 % albuminuria, and 22 % neuropathy. Legal blindness was prevalent (5 %) but clinical nephropathy (7 %) and foot ulcers (1 %) were uncommon in persons with diagnosed diabetes. Among people with diagnosed diabetes, microvascular and neuropathic complications were associated with hyperglycaemia. Retinopathy was also associated with duration of diabetes; albuminuria with hypertension and hypercholesterolaemia; and neuropathy with age, female sex, and hypercholesterolaemia. Albuminuria was as common in people with previously undiagnosed diabetes (22 %) as those with diagnosed disease (21 %). Mean haemoglobin A 1c was lower (7.8 %) and retinopathy (16 %) and neuropathy (14 %) were less prevalent in people with previously undiagnosed disease. Ocular conditions, blindness, and neuropathy were prevalent in the non-diabetic population. The microvascular and neuropathic complications of diabetes are a major clinical and public health problem in Egypt. Copyright © 1998 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34940/1/696_ftp.pd
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