23 research outputs found

    Experimental and Ab initio Computational Study of Azobenzene and Several of its Derivatives

    Get PDF
    In this dissertation we studied azobenzene and seven of its derivatives experimentally in addition to comprehensive ab initio computational investigation. Gas phase ion chemistry studies sre a rich and important area of chemical physics. We used an energy resolved collision induced dissociation technique to study the chemical bonding of these molecule negative or positive ions. We studied the fragment ions which we have detected in the mass spectrum computationally as well. Doing so we experimentally measured the bond dissociation energies and compared them with those resulting from the quantum chemistry computations. We also performed other experiments such as Raman spectroscopy, NMR spectroscopy and UV-Vis spectroscopy to experimentally study the electronic structure of these molecules. We have utilized state of the art computational algorithms such as high accuracy multi-level calculations to study thermochemical properties of the parent neutral molecules as well as precursor and fragment negative and positive ions and neutrals. We have calculated electron affinities and compared results from different methods such as density functional theory methods and perturbative methods such as MP2 with multi-level high accuracy calculations to compare their performances. Many high accuracy multi-level calculations which we have done results compared with the experimental results can provide an accurate benchmark for comparing the performance of different theoretical methods for different molecules and ions. Comparing our experimental results for electron affinities and bond dissociation energies with theoretically obtained results, we have proved the ab initio computational results can be accurate and close to those can be measured experimentally

    Quantum Face Recognition Protocol with Ghost Imaging

    Get PDF
    Face recognition is one of the most ubiquitous examples of pattern recognition in machine learning, with numerous applications in security, access control, and law enforcement, among many others. Pattern recognition with classical algorithms requires significant computational resources, especially when dealing with high-resolution images in an extensive database. Quantum algorithms have been shown to improve the efficiency and speed of many computational tasks, and as such, they could also potentially improve the complexity of the face recognition process. Here, we propose a quantum machine learning algorithm for pattern recognition based on quantum principal component analysis (QPCA), and quantum independent component analysis (QICA). A novel quantum algorithm for finding dissimilarity in the faces based on the computation of trace and determinant of a matrix (image) is also proposed. The overall complexity of our pattern recognition algorithm is O(Nlog N) -- N is the image dimension. As an input to these pattern recognition algorithms, we consider experimental images obtained from quantum imaging techniques with correlated photons, e.g. "interaction-free" imaging or "ghost" imaging. Interfacing these imaging techniques with our quantum pattern recognition processor provides input images that possess a better signal-to-noise ratio, lower exposures, and higher resolution, thus speeding up the machine learning process further. Our fully quantum pattern recognition system with quantum algorithm and quantum inputs promises a much-improved image acquisition and identification system with potential applications extending beyond face recognition, e.g., in medical imaging for diagnosing sensitive tissues or biology for protein identification.BERC.2018-2021 Severo Ochoa.SEV-2017-071

    Diagnostic value of standard electrocardiogram in acute right ventricular myocardial infarction

    Get PDF
    Myocardial infarction (MI) (i.e., heart attack) is the irreversible death (necrosis) of heart muscle secondary to prolonged lack of oxygen supply (ischemia) which accounts for a large number of deaths in the hospital. Diagnosis of myocardial infarction is confirmed based on clinical manifestations and electrocardiographic changes along with increased cardiac enzymes. Electrocardiogram (ECG) is one of the safest and easiest methods in the first place. Therefore, this study aimed to investigate the diagnostic value of standard electrocardiogram in the diagnosis of acute right ventricular infarction following lower cardiac infarction. This research was carried out at a time interval of one and a half years to diagnose acute primary infarction. In this method, the diagnostic value of ST↓ in lead I, ST↓ in lead aVL and I ST↓ + aVL, compared with ST↑ in lead V4R was investigated for diagnosis of right ventricular infarction. ST↑ in the lead V4R is a gold standard for the detection of right ventricular MI. All the patients who had the inclusion criteria were allowed to participate in the study. A total of 66 patients participated in the study. Accordingly, 58 (87%) were male and 8 (13%) were female. The mean age of the population was 54.9 ± 11.41. According to the ST↑ standard in lead V4R, 26 patients (39%) had right ventricular myocardial infarction. There was no significant relationship between angina pectoris and premature infarction (P-Value = 0.869). In this study, the right ventricular was most commonly involved in right coronary artery (RCA) (78%). There was no significant relationship between the occlusion of right coronary artery and right ventricular infarction in 60 patients (P-Value = 0.94). The results showed that electrocardiogram manifestations help determine the occlusion site and the area at risk (ST↓ in lead aVL and aVL + I, sensitivity = 96%). In myocardial infarction, symptoms such as the ST-Segment elevation in lead aVR and ST-Segment depression in the lower leads are possible. Accordingly, in the lower infarction, ST changes in the leads V1-V6 are helpful in detecting patients at risk. Thus, the use of electrocardiogram in acute myocardial infarction (AMI) helps detect more invasive patients and prevents extensive myocardial damage and other complications

    Theoretical and practical aspects of the design and production of synthetic holograms for transmission electron microscopy

    Get PDF
    Beam shaping-the ability to engineer the phase and the amplitude of massive and massless particles-has long interested scientists working on communication, imaging, and the foundations of quantum mechanics. In light optics, the shaping of electromagnetic waves (photons) can be achieved using techniques that include, but are not limited to, direct manipulation of the beam source (as in X-ray free electron lasers and synchrotrons), deformable mirrors, spatial light modulators, mode converters, and holograms. The recent introduction of holographic masks for electrons provides new possibilities for electron beam shaping. Their fabrication has been made possible by advances in micrometric and nanometric device production using lithography and focused on ion beam patterning. This article provides a tutorial on the generation, production, and analysis of synthetic holograms for transmission electron microscopy. It begins with an introduction to synthetic holograms, outlining why they are useful for beam shaping to study material properties. It then focuses on the fabrication of the required devices from theoretical and experimental perspectives, with examples taken from both simulations and experimental results. Applications of synthetic electron holograms as aberration correctors, electron vortex generators, and spatial mode sorters are then presented

    Global burden of peripheral artery disease and its risk factors, 1990–2019 : a systematic analysis for the Global Burden of Disease Study 2019

    Get PDF
    peripheral artery disease were modelled using the Global Burden of Disease, Injuries, and Risk Factors Study (GBD) 2019 database. Prevalence, disability-adjusted life years (DALYs), and mortality estimates of peripheral artery disease were extracted from GBD 2019. Total DALYs and age-standardised DALY rate of peripheral artery disease attributed to modifiable risk factors were also assessed. Findings In 2019, the number of people aged 40 years and older with peripheral artery disease was 113 million (95% uncertainty interval [UI] 99·2–128·4), with a global prevalence of 1·52% (95% UI 1·33–1·72), of which 42·6% was in countries with low to middle Socio-demographic Index (SDI). The global prevalence of peripheral artery disease was higher in older people, (14·91% [12·41–17·87] in those aged 80–84 years), and was generally higher in females than in males. Globally, the total number of DALYs attributable to modifiable risk factors in 2019 accounted for 69·4% (64·2–74·3) of total peripheral artery disease DALYs. The prevalence of peripheral artery disease was highest in countries with high SDI and lowest in countries with low SDI, whereas DALY and mortality rates showed U-shaped curves, with the highest burden in the high and low SDI quintiles. Interpretation The total number of people with peripheral artery disease has increased globally from 1990 to 2019. Despite the lower prevalence of peripheral artery disease in males and low-income countries, these groups showed similar DALY rates to females and higher-income countries, highlighting disproportionate burden in these groups. Modifiable risk factors were responsible for around 70% of the global peripheral artery disease burden. Public measures could mitigate the burden of peripheral artery disease by modifying risk factors

    Natural convection of Al2O3-water nanofluid with variable properties in a square enclosure with heat source and heat sink on the vertical walls

    No full text
    The buoyancy-driven fluid flow and heat transfer in a square cavity with partially active side walls filled The buoyancy-driven fluid flow and heat transfer in a square cavity with partially active side walls filled which the length is equal to half of height and width is 0.1 of height respectively so that it contains Al_2 O_3âwater nanofluid which variable properties, has been investigated numerically. The active parts of the left and the right side walls of the cavity are maintained at temperatures Th and Tc , respectively, with Th>Tc . The enclosureâs top and bottom walls as well as the inactive parts of its side walls are kept insulated. The governing equations in the two-dimensional space are discretized using the control volume method. A proper upwinding scheme is employed to obtain stabilized solutions. Using the developed code, a parametric study is undertaken, and the effects of the Rayleigh number, the locations of the active parts of the side walls and the volume fraction of the nanoparticles on the fluid flow and heat transfer inside the cavity are investigated. It is observed from the results that the average Nusselt number increase with increasing the Rayleigh number and decrease with increasing the volume fraction of the nanoparticles. Moreover, the maximum average Nusselt number for the high and the low Rayleigh numbers occur for the bottomâmiddle locations of the thermally active parts, respectively

    Subcosto-midline Abdominal Incision: A New Incision for Resection of Large Renal Masses with or without Vascular Involvement

    No full text
    Background: Renal cell carcinoma is the third most common urological cancer.Surgical resection is still the mainstay of treatment for this tumor. Here we present anew surgical approach for the management of locally advanced renal cell carcinoma.Methods: We chose ten patients with extensive renal masses. The patient, undergeneral anesthesia after preparation and draping, was placed in the supine position. Wemade either a right or left classic subcostal incision which was then extended as a midlineincision through the linea alba to the lower abdomen. After mobilization of the rightascending or left descending colon, the renal artery and vein were detected, ligated anddivided. Next, the involved kidney was released from the adjacent structures andremoved, including Gerota’s fascia.Results: The study included 6 men (60%) and 4 women (40%) with a mean ageof 57 years. Mean blood loss was 1500 mL and mean operative time was 180 minutes.The patients' surgical wounds were checked for two weeks after the operation; noneof the patients developed wound infections or dehiscence. At the time of writing thismanuscript, in January 2011, 7 patients (70%) were alive with no evidence of abdominalherniation at the surgical site.Conclusion: A subcosto-midline incision or anterior triangular flap incision is amodified abdominal incision. In our experience, this incision is useful for the resectionof locally advanced large renal masses

    Association of childhood croup and increased incidence of airway hyperreactivity in adulthood

    No full text
    BACKGROUND: Some evidence suggests that childhood croup could be associated with increased incidence of adulthood bronchial reactivity, but its significance is uncertain. The aim of the present study was to evaluate the long-term outcome of early life croup. PATIENTS AND METHODS: This case–control study was conducted in 2010–2012 in Isfahan, Iran. The case group consisted of 164 adolescents with a history of severe croup in early life and an equal number of healthy controls without any history of croup or other chronic or recurrent respiratory diseases. The two groups were compared according to pulmonary function tests and bronchial reactivity (exercise challenge test). Statistical analyses were performed using the SPSS software package, version 20 (SPSS Inc., Chicago, IL, USA). P < 0.05 was considered significant. RESULTS: Baseline spirometric values (forced expiratory volume in 1st s (FEV1), forced volume capacity (FVC), FEV1/FVC, and forced expiratory flow at 25%–75% (FEF25–75) were similar in case and control groups. A reduction in FEV1 and FEF25–75 after exercise challenge test was seen in 9% and 12.8% of patients, respectively, whereas this was reduced in only 4.2% and 6.1% of the controls (P = 0.034 and P = 0.021, respectively). CONCLUSION: Our findings suggest that childhood croup might be a predisposing factor for bronchial hyperreactivity in adulthood. Longitudinal studies are necessary to confirm the clinical significance of these findings
    corecore