183 research outputs found

    A hybrid analysis model supported by machine learning algorithm and multiple linear regression to find reasons for unemployment of programmers in Iraq

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    The problem of unemployment is one of the most important problems faced by most countries of the world, and it is one of the intractable problems in developing countries, and in Iraq unemployment occupies great importance due to its high rates. This problem in itself is a serious condition, because it results from mismanagement and the structure of the economy, and despite its great importance, it has not been carefully monitored. There are studies and strategies that deal with the analysis and study of those causes that lead to this problem, such as traditional statistical methods, various mathematical and statistical methods, in this research proposed a method uses machine learning methods to find the factors that affect the causes of this problem, as well as the multiple linear regression method

    Generalized Thermo-Viscoelasticity under Three Theories

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    The model of the equations of the two-imensional generalized thermo-viscoelasticity based on Lord-Shulman (L-S), Green and Lindsay (G-L) and Classical dynamicalcoupled (CD) theories are studied. The normal mode analysis is used to obtain the exact expressions for the temperature distribution, displacement components, and the thermal stresses. The resulting formulation is applied to two different concrete problems. The first concerns to the case of a heat punch across the surface of a semi-infinite thermoviscoelastic half-space subject to appropriate boundary conditions. The second deals with a plate with thermo-isolated surfaces subjected to a time-dependent compression. A comparison is carried out between temperature, displacement and stress as calculated for each problem from view of the different theories of generalized thermo-viscoelasticity. Numerical results are given and illustrated graphically. Comparisons are made with the results predicted by three theories. The analysis presented in this paper is more general than any previous investigation

    Synthesis and Characterization of Dibutyltin(IV) Comp)exes of Substituted Catechol

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    The complexes of dibutyltin (IV) with anions of 4-tert-buty1catechol, 4chlorocatechol, 4-nitrocatechol, 3,4-dihydroxybenzaldehyde, and 3,4dihydroxybenzoic acid were synthesized by reacting dibutyltin (IV) oxide with the corresponding free ligands. The isolated complexes were characterized by elemental analysis and spectroscopic methods such as infrared, lH and 13C NMR. Complex formation between the dibutyltin(IV) moiety and the anions of 4-tert-butylcatechol, 4-chlorocatechol, 4-nitrocatechol and 3,4dihydroxybenzaldehyde takes place with chelation at the o-hydroxy positions. However, results of analysis carried out on the dibutyltin (IV) complex of 3,4dihydroxybenzoic acid showed that the carboxylic group is also involved in chelate formation. Results of the lethality bioassay on the brine hrimp (Artemia salina) indicated that all the complexes have biological activity but only the 4tert- buty1catechol complex was able to cleave D A (plasmid pBR 322)

    Systematic Evaluation for the Impact of the Geological Conditions on the Adsorption Affinities of Calcite as an Adsorbent of Zn2+ Ions from Aqueous Solutions: Experimental and Theoretical Studies

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    Three samples of calcite (calcite crystal (CA), calcite of limestone (L.CA), and metamorphosed calcite (marble) (M.CA)) were assessed as adsorbents of Zn (II) to consider the impact of the different geological conditions. The three samples exhibit remarkable changes in their Zn (II) retention capacities (Qsat = 384.6 mg/g (CA), 274.5 mg/g (L.CA), and 512.6 mg/g (M.CA)). The retention systems of the three calcite samples were described on the basis of the suggested statistical physics-based equilibrium studies as well as the traditional kinetic and isotherm models. However, the M.CA samples exhibited the best retention capacity, the steric properties reflecting a higher active site density of CA (Nm (Zn) = 113.46 mg/g) than both M.CA (Nm (Zn) = 82.8 mg/g) and L.CA (Nm (Zn) = 52.4 mg/g) at 323 K. This was assigned to the controlling effect of the sequestered numbers of Zn (II) per site on the surfaces of the calcite phase (n(Zn) = 3.39 (CA), 5.24 (L.CA), and 6.19 (M.CA)) in addition to the higher surface area and ion exchange of the metamorphosed and deformed M.CA. The previous n(Zn) values suggested the retention of Zn (II) by a multi-ionic mechanism in a vertical orientation. The Gaussian energies (8 to 16 KJ/mol) and retention energies (˂40 KJ/mol) of Zn (II) by CA and L.CA suggested complex physical and weak chemical mechanisms involving ion exchange, hydrogen bonding, dipole bonding forces, electrostatic attractions, and van der Waals forces. The thermodynamic properties were illustrated on the basis of the internal energy, free enthalpy, and entropy functions, which validate the endothermic and spontaneous nature of the Zn (II) retention system by the three calcite samples

    Propagation of Plane Waves in Generalized Piezo-thermoelastic Medium: Comparison Of Different Theories

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    ABSTRACT: In this paper, a general solution for the propagation of plane waves in generalized piezo-thermoelastic medium for two-dimensional problem under the different thermoelastic theories is investigated. We have included Coupled theory (CT), Lord-Schulman (L-S) and Green-Lindsay (G-L) theories. The normal mode analysis is used to obtain the exact expressions for the considered variables. The results of the physical quantities have been illustrated graphically by comparison between (CT), (L-S) and (G-L) theories. KEYWORDS: Piezo-thermoelastic, Relaxation time, Normal mode analysis, Generalized thermoelasticity. I INTRODUCTION Piezoelectric is considered one of the basic properties of crystals, ceramics, polymers, liquid crystals and some biological tissues (e.g. bone and tendon). Recent interest in the piezoelectric materials stems from their potential applications in intelligent structural systems, and piezoelectric is currently enjoying a greatest resurgence in both fundamental research and technical applications. The theory of thermo-piezoelectric was first proposed by Mindlin Thermoelasticity theories that predict a finite speed for the propagation of thermal signals have aroused much interest in the last three decades. These theories are known as generalized thermoelasticity theories. The first generalization of the thermoelasticity theory is due to Lord and Shulman [8] who introduced the theory of generalized thermoelasticity with one relaxation time through postulating a new law of heat conduction to replace the classical Fourier' law. This law contains the heat flux vector as well as its time derivative. It contains also a new constant that acts as a relaxation time. The heat equation of this theory is of the wave-type which ensuring finite speeds of propagation of heat and elastic waves. The remaining, governing equations for this theory, namely, the equations of motion and the constitutive relations remain the same as those for the coupled and the uncoupled theories. This theory was extended by Dhaliwal and Sherief [9] to general anisotropic media in the presence of heat sources. Othman [10] studied the Lord

    Effect of early clinical skills teaching on 3rd year medical students' learning: The student perspective

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    AbstractObjectivesThe main purpose of the early introduction of Clinical Skills Learning (CSL) to pre-clinical years is to allow medical students to gain experience in clinical examination skills, basic medical procedures, history-taking and clinical communication. The objective of this study was to determine the effectiveness of the early teaching of clinical skills in preparing medical students for their clinical years.MethodsA validated questionnaire assessing the value of CSL on students in their first clinical year was distributed to 3rd year medical students. The questionnaire consisted of 8 items with a five-point Likert scale and one open-ended question.ResultsThe response rate to the questionnaire was approximately 62%. Nearly 97 (70.8%) students suggested that CSL was a favourable teaching strategy. A high percentage of students (90.5%) agreed that CSL was a useful pre-clinical module to prepare them for their clinical years. The students gave positive feedback on the teaching of history-taking and physical examination, exposure to the hospital environment and acquisition of communication skills with supervisors and patients. No student perceived the CSL module as poor.ConclusionsEarly CSL was well-perceived by students in preparing them for their clinical years. CSL is a vital part of the pre-clinical curriculum and should be further enriched with frequent hospital visits to enhance students' confidence level and performance when interacting with patients during their clinical years

    Design, synthesis, and biological investigation of oxadiazolyl, thiadiazolyl, and pyrimidinyl linked antipyrine derivatives as potential non-acidic anti-inflammatory agents

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    A novel series of 12 antipyrine derivatives containing 1,3,4-oxadiazoles (4a-d), 1,3,4-thiadiazoles (6a-d), and pyrimidines (8a-d), was preparedand assessed for its potential in vitro COX-2 inhibitors. Compared to Celecoxib, compounds 4b-d and 8d were the most potent derivatives c with a half-maximal inhibitory concentration range of 53-69 nM. Considering COX-2 selectivity index, compounds 4 b and 4c were chosen among these most potent derivatives for further investigation. The in vivo ability of compounds 4 b and 4c to counteract carrageenan-induced paw edoema has been assessed and their potential underlying mechanisms have been elucidated and the results have been further validated using molecular docking simulations

    Effect of extraction procedure on the yield and biological activities of hydroxychavicol from Piper betle L. leaves

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    Piper betle Linn is one of the most common ethnomedicinal plants with its extract being popularly used in the modern product to enhance functionality. However, extraction methods always lead to differences in biological activities. The objectives of this study were to evaluate the effects of the extraction methods on the yield and biological activities of hydroxychavicol from P. betle L. extracts and to determine the correlation between the hydroxychavicol content and biological activities of P. betle L. extracts such as antioxidant, antimicrobial, and anticancer properties. The purity of the hydroxychavicol and its concentration (quantitative) in the crude extracts were also evaluated using a reverse-phase HPLC while GC–MS was employed to determine other components (qualitative). The results showed that only certain extraction procedures gave high yields of hydroxychavicol as well as remarkable biological activities. The chloroform extract following boiling with water (M2) gave the highest percentage of hydroxychavicol content based on the HPLC analysis. M2 and pure hydroxychavicol actively inhibited all the five cancer cell lines studied except A549. M2 showed more effective inhibition activity against MCF 7 with an IC50 of 1.74 ug/mL. M2 extract also showed strong antibacterial activity against all the bacteria strains as well as a strong antifungal activity against Candida albicans. There was, however, a weak correlation between the hydroxychavicol content and the biological activities of P. betle L. extracts. In conclusion, extraction procedures greatly affect the yield and biological activities of hydroxychavicol from P. betle L. The designation of a single compound such as hydroxychavicol as a bioactive chemical marker compound in the P. betle L. extracts, however, is not enough to determine the biological activities of the extract

    Clinical and histopathological responses to bee venom phonophoresis in treating venous and diabetic ulcers: a single-blind randomized controlled trial

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    IntroductionChronic venous and diabetic ulcers are hard to treat that cause patients long time of suffering as well as significant healthcare and financial costs.PurposeThe conducted study was to evaluate the efficacy of bee venom (BV) phonophoresis on the healing of chronic unhealed venous and/or diabetic foot ulcers Also, to compare the healing rate of diabetic and venous ulcers.MethodologyThe study included 100 patients (71 males and 29 females) with an age range of 40-60 years' old who had chronic unhealed venous leg ulcers of grade I, grade II, or diabetic foot ulcers with type II diabetes mellitus. They randomly assigned into four equal groups of 25: Group A (diabetic foot ulcer study group) and group C (venous ulcer study group) who both received conservative treatment of medical ulcer care and phonophoresis with BV gel, in addition to group B (diabetic foot ulcer control group) and group D (venous ulcer control group) who both received conservative treatment of medical ulcer care and received ultrasound sessions only without BV gel. Wound surface area (WSA) and ulcer volume measurement (UVM) were used to assess the ulcer healing pre-application (P0), post-6 weeks of treatment (P1), and after 12 weeks of treatment (P2). In addition to Ki-67 immunohistochemistry was used to evaluate the cell proliferative in the granulation tissue of ulcers pre-application (P0) and after 12 weeks of treatment (P2) for all groups.ResultsThis research revealed a statistical significance improvement (p ≤ 0.0) in the WSA, and UVM with no significant difference between study groups after treatment. Regarding Ki-67 immunohistochemistry showed higher post treatment values in the venous ulcer group in comparison to the diabetic foot ulcer group.ConclusionBee venom (BV) provided by phonophoresis is effective adjuvant treatment in accelerating venous and diabetic foot ulcer healing with higher proliferative effect on venous ulcer.Clinical trial registrationwww.ClinicalTrials.gov, identifier: NCT05285930
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