1,028 research outputs found

    Rhazes, pionir koji je pridonio istraživanju u medicinskoj praksi

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    Medical history explains that Persian physicians used scientific methods based on clinical experiences and observations for treatment from pre-Islamic time (before 637 AD) and centuries later (in the Islamic era). Rhazes was one of the Persian physicians acknowledged as a pharmacist, chemist and prominent scientific writer on various subjects of medicine and philosophy. In this study, we aimed to investigate clinical experiences, as well as the ethical and critical views of Rhazes in medical practice. Rhazes promoted ethics in the medical profession. He expressed critical key points about ancient written texts. He broke ancient physicians’ taboos in medical theories and evaluated them based on his own experiences. He designed animal and preclinical evaluations for his theories and also performed the first clinical trials with control groups in the history. His critical views about medical sciences as well as his beliefs in experiments resulted in many medical, chemical and pharmaceutical findings. Therefore, in history, he can be considered as the pioneer in using trials and experiments for approving medical methods.Medicinska povijest pokazuje da su se perzijski liječnici služili znanstvenim metodama u liječenju, temeljenim na kliničkim iskustvima i promatranjima još od predislamskog vremena (prije 637. godine) i stoljećima poslije (u islamskom dobu). Rhazes je bio jedan od perzijskih liječnika priznat kao ljekarnik, kemičar i istaknuti znanstveni pisac o različitim temama iz medicine i filozofije. U ovom radu nastojali smo istražiti klinička iskustva, kao i etičke i kritičke stavove Rhazesa u medicinskoj praksi. Rhazes je promovirao etiku u medicinskoj struci. Iznio je kritične ključne točke o antičkim pisanim tekstovima. Srušio je drevne liječničke tabue u medicinskim teorijama i procijenio ih na temelju vlastita iskustva. Provodio je evaluacije za svoje teorije na životinjama i u predklinici te proveo i prva klinička ispitivanja s kontrolnim grupama u povijesti. Njegova kritička stajališta o medicinskim znanostima, kao i vjerovanje u eksperimente rezultirali su mnogim medicinskim, kemijskim i farmaceutskim otkrićima. Stoga se Rhazesa u povijesti može smatrati pionirom u korištenju ispitivanja i eksperimenata za odobravanje medicinskih metoda

    Rhazes, pionir koji je pridonio istraživanju u medicinskoj praksi

    Get PDF
    Medical history explains that Persian physicians used scientific methods based on clinical experiences and observations for treatment from pre-Islamic time (before 637 AD) and centuries later (in the Islamic era). Rhazes was one of the Persian physicians acknowledged as a pharmacist, chemist and prominent scientific writer on various subjects of medicine and philosophy. In this study, we aimed to investigate clinical experiences, as well as the ethical and critical views of Rhazes in medical practice. Rhazes promoted ethics in the medical profession. He expressed critical key points about ancient written texts. He broke ancient physicians’ taboos in medical theories and evaluated them based on his own experiences. He designed animal and preclinical evaluations for his theories and also performed the first clinical trials with control groups in the history. His critical views about medical sciences as well as his beliefs in experiments resulted in many medical, chemical and pharmaceutical findings. Therefore, in history, he can be considered as the pioneer in using trials and experiments for approving medical methods.Medicinska povijest pokazuje da su se perzijski liječnici služili znanstvenim metodama u liječenju, temeljenim na kliničkim iskustvima i promatranjima još od predislamskog vremena (prije 637. godine) i stoljećima poslije (u islamskom dobu). Rhazes je bio jedan od perzijskih liječnika priznat kao ljekarnik, kemičar i istaknuti znanstveni pisac o različitim temama iz medicine i filozofije. U ovom radu nastojali smo istražiti klinička iskustva, kao i etičke i kritičke stavove Rhazesa u medicinskoj praksi. Rhazes je promovirao etiku u medicinskoj struci. Iznio je kritične ključne točke o antičkim pisanim tekstovima. Srušio je drevne liječničke tabue u medicinskim teorijama i procijenio ih na temelju vlastita iskustva. Provodio je evaluacije za svoje teorije na životinjama i u predklinici te proveo i prva klinička ispitivanja s kontrolnim grupama u povijesti. Njegova kritička stajališta o medicinskim znanostima, kao i vjerovanje u eksperimente rezultirali su mnogim medicinskim, kemijskim i farmaceutskim otkrićima. Stoga se Rhazesa u povijesti može smatrati pionirom u korištenju ispitivanja i eksperimenata za odobravanje medicinskih metoda

    Leaf biomass and leaf area equations for three planted trees in Iran

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    Leaf area (LA) and leaf biomass (LB) are important variables for most physiological, horticultural and agronomic studies involving plant growth, development rate, radiation use efficiency, and water or nutrient use. Measuring these variables need destructive and aggressive sampling. Fortunately, evolving allometric equations can help for low cost and non-destructive estimation of such variables. The aims of this study are Estimate, compare and develop allometric models of LA and LB per tree and per stand for Alnus subcordata (AS), Populus deltoides (PD) and Taxodium distichum (TD) plantations. We selected 12 sample trees in each stand. Leaf Fresh weight of randomly selected branches was weighted in the field. Branch-level LA was modeled as a function of branch diameter (R2 > 0.8) and total fresh weight of LB has been calculated for each sampled tree. For each species, 100 leaves from all canopy directions of trees were randomly selected and transported to the laboratory. At the lab, leaf area has been measured using leaf area meter. Allometric equations were derived using regression analysis. For all species, derived equations showed high accuracy (R2 ranged from 0.837 to 0.947). However, with respect to mean square error, power regression equations (individual leaf area = a(L×W)b and LA or LB = a DBHb) are best models to estimate Individual Leaf Area, LA, and LB of AS, PD, and PD. The highest LAI was in the order of 16.9 > 5.5 > 4.5 for AS, PD, and TD, respectively. DOI: http://dx.doi.org/10.5281/zenodo.26791

    Rhazes, pionir koji je pridonio istraživanju u medicinskoj praksi

    Get PDF
    Medical history explains that Persian physicians used scientific methods based on clinical experiences and observations for treatment from pre-Islamic time (before 637 AD) and centuries later (in the Islamic era). Rhazes was one of the Persian physicians acknowledged as a pharmacist, chemist and prominent scientific writer on various subjects of medicine and philosophy. In this study, we aimed to investigate clinical experiences, as well as the ethical and critical views of Rhazes in medical practice. Rhazes promoted ethics in the medical profession. He expressed critical key points about ancient written texts. He broke ancient physicians’ taboos in medical theories and evaluated them based on his own experiences. He designed animal and preclinical evaluations for his theories and also performed the first clinical trials with control groups in the history. His critical views about medical sciences as well as his beliefs in experiments resulted in many medical, chemical and pharmaceutical findings. Therefore, in history, he can be considered as the pioneer in using trials and experiments for approving medical methods.Medicinska povijest pokazuje da su se perzijski liječnici služili znanstvenim metodama u liječenju, temeljenim na kliničkim iskustvima i promatranjima još od predislamskog vremena (prije 637. godine) i stoljećima poslije (u islamskom dobu). Rhazes je bio jedan od perzijskih liječnika priznat kao ljekarnik, kemičar i istaknuti znanstveni pisac o različitim temama iz medicine i filozofije. U ovom radu nastojali smo istražiti klinička iskustva, kao i etičke i kritičke stavove Rhazesa u medicinskoj praksi. Rhazes je promovirao etiku u medicinskoj struci. Iznio je kritične ključne točke o antičkim pisanim tekstovima. Srušio je drevne liječničke tabue u medicinskim teorijama i procijenio ih na temelju vlastita iskustva. Provodio je evaluacije za svoje teorije na životinjama i u predklinici te proveo i prva klinička ispitivanja s kontrolnim grupama u povijesti. Njegova kritička stajališta o medicinskim znanostima, kao i vjerovanje u eksperimente rezultirali su mnogim medicinskim, kemijskim i farmaceutskim otkrićima. Stoga se Rhazesa u povijesti može smatrati pionirom u korištenju ispitivanja i eksperimenata za odobravanje medicinskih metoda

    EBSD characterization of nano/ultrafine structured Al/Brass composite produced by severe plastic deformation

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    In the present work, nano/ultrafine structured Al/Brass composite was produced by accumulative roll bonding (ARB) up to eight cycles. The evolution of grain refinement and deformation texture and their effect on the mechanical properties were investigated. It was observed that by increasing the ARB cycles, due to the difference in flow properties of the metal constituents, brass layers necked, fractured and distributed in aluminum matrix. After eight cycles, a composite was produced with almost homogeneous distribution of brass fragments in aluminum matrix. Microstructural characterization by electron backscatter diffraction (EBSD) revealed the formation of bimodal structure consisting of equiaxied grains with an average size of ~120 nm and elongated grains after eight cycles, which was attributed to the occurrence of redundant shear and recrystallization. The crystallographic texture results indicated that the major texture components in the aluminum matrix were Brass {011}, S {123}, Goss {011} and Rotated Goss {011}. Moreover, it was concluded that Goss {011} and Rotated Goss {011} components appeared for high number of ARB cycles due to the adiabatic heat during ARB processing. The tensile strength of Al/Brass composite reached 330 MPa, which was 4.23 times and 1.83 times higher than those of annealed aluminum and monolithic aluminum, respectively. Finally, fracture surfaces of samples were studied, using field emission scanning electron microscope (FESEM), to reveal the failure mechanism
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