Cerebral Blood Flow Measurement Using MRI: Mathematical Regularization and Phantom Evaluation.

Strokes have been the third most prevalent cause of death in developed countries and the second most prevalent cause of mortality worldwide. Ischemic strokes are by far the most common type of strokes. Verifying the extent and severity of brain damage may be the most challenging problem in the diagnosis and treatment of stroke. Magnetic resonance imaging provides important indicators, such as cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transition time (MTT), for tissues at the risk for acute strokes. These perfusion-related parameters can be estimated using MR techniques, specifically as dynamic susceptibility contrast (DSC). The DSC technique measures the change in MR signal during the passage of a non-diffusible tracer through the brain tissue. The signal change can be related to the blood flow through a mathematical convolution model, originally suggested by Meier and Zierler, based on indicator-dilution theory. There have been many attempts to find a deconvolution algorithm that overcomes the many limitations, especially, the instability issue of this ill-posed problem. We have suggested a new approach based on the framework of Tikhonov regularization which we will refer to that as "Generalized Tikhonov". Using computer simulations, this method proved promising for blood flow estimation in the presence of the major sources of error: noise, tracer delay and dispersion. In comparison to the standard Tikhonov regularization, our method showed less sensitivity to the changes in regularization parameters that determine the extent of the regularization. To investigate the model we have designed a perfusion phantom which is very similar to actual tissues in terms of perfusion-related parameters such as blood volume, blood flow and the flow transition time. The signal to noise ratio, due to the similarity of the flow volume, is similar to that in actual perfusion measurements. The phantom has the capability of including or excluding the tracer delay and dispersion depending on the desired nature of experiments. Flow at every point of the phantom can be calculated using finite element methods. The perfusion phantom was used to verify the accuracy of the Generalized Tikhonov method and to compare it to the conventional methods.Ph.D.Biomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/61616/4/Ebrahimi.pd

Relationship between social media marketing practices and customer response with mediating role of brand equity dimensions: an empirical investigation

This study aims to investigate the relationship between social media marketing practices and customer response with consideration of the mediating role of brand equity dimensions through structural equation modeling in an empirical case study. Data are analyzed using structural equation modeling. The following findings are found: The results show that there is a significant relationship between social media marketing practices and customer response in the survey sample. Additionally, the hypothesis about the mediating role of brand equity dimensions is also supported. The results of our research augment our understanding of the role of social media marketing practices in stimulating customer response (electronic word-of-mouth and commitment) and the role of brand equity dimensions (brand awareness and brand image)

The Effect of Corporate Social Responsibility on Brand Performance with the Mediating Role of Corporate Reputation, Resource Commitment and Green Creativity

Following the strategic decisions of business managers in the community, issues have been raised that lead to changes in the community. One of these issues, which is becoming increasingly important, is consideration of corporate social responsibility. Therefore, the focus of this study was the effect of corporate social responsibility on brand performance with the mediating role of corporate reputation, resource commitment and green creativity. The research method was survey. The statistical population was employees of private banks, 507 of whom participated in the study. Structural equation modelling with SMARTPLS software was used to analyse the data. The results showed the effect of corporate social responsibility is positive and significant on resource commitment, green creativity, corporate reputation and brand performance. The effect of resource commitment, green creativity and corporate reputation is positive and significant on brand performance. Brand performance will be improved if the company supports employee higher education, encourages employees to develop their skills and abilities, implements flexible policies to provide work-life balance for employees, prioritizes employee needs and demands, has plans to reduce the negative effects of the company on the environment, and participates in activities aimed at protecting and improving the quality of the environment

تاثیر استفاده از چک لیست بر بهبود کیفیت شرح حال گیری بیماران ترومایی

Introduction: To date, no study with a proper sample size has been done to evaluate the efficiency of using pre-designed checklists in history taking of trauma patients in Iran. Therefore, the present study was designed to evaluate the pre-designed checklist’s effects on the quality of history taking in trauma patients referred to the emergency department (ED). Methods: In the present prospective cross-sectional study, data of the trauma patients presented to the ED were recorded either with or without using a checklist, randomly. The designed checklist consisted of personal data, trauma mechanism, wound characteristics and trauma severity, severity and location of injuries, and the patient’s diagnostic and therapeutic plans. The quality of data gathering in each evaluated item was divided into 3 groups of complete recording, incomplete recording, and not recorded. Data recording quality was compared between the 2 groups using chi square or exact Fisher’s test. In all analyses, p < 0.05 was defined as significance level. Results: In the preset study, patient data were gathered without using a checklist in 795 and using a checklist in 384 cases. Complete and accurate data recording in all items was more frequent in the group that had used the checklist (p < 0.001). Recording injury location without using a checklist was complete in only 20.8% of the cases. This rate increased to 95.6% when the checklist was used. In addition, complete and accurate recording of the diagnostic plan increased from 9% to 72.8%, and complete and accurate recording of the therapeutic plan raised from 14% to 68.7%. The improvements in data recording quality was significant in all cases. Conclusion: It seems that using pre-designed checklists for history taking in trauma patients, leads to a significant increase in quality of data recording and history taking. مقدمه: تاکنون مطالعه ای با حجم نمونه قابل قبول به منظور کارایی استفاده از چک لیست های از پیش طراحی شده در جمع آوری داده های پزشکی بر بالین بیماران ترومایی در کشور انجام نشده است. بر این مبنا مطالعه حاضر با هدف بررسی تاثیر استفاده از چک لیست از پیش طراحی شده بر کیفیت ثبت شرح حال بیماران ترومایی مراجعه کننده به بخش اورژانس طراحی شد. روش کار: در مطالعه مقطعی آینده نگر حاضر ثبت داده های بیماران ترومایی مراجعه کننده به بخش اورژانس به صورت تصادفی به دو روش استفاده از چک لیست و بدون استفاده از آن انجام پذیرفت. چک لیست طراحی شده حاوی قسمت های اطلاعات فردی، مکانیسم تروما، عمق تشریحی و شدت تروما، اندازه ضایعات، محل ضایعات و برنامه تشخیصی و درمانی بیمار بود. وضعیت تکمیل داده ها در هر یک از آیتم های مورد بررسی به سه طبقه ثبت کامل، ثبت ناقص و عدم ثبت تقسیم گردید. مقایسه وضعیت تکمیل داده ها بین دو گروه، با استفاده از آزمون کای دو یا تست دقیق فیشر انجام شد. در تمامی آنالیزها 05/0>p به عنوان سطح معنی داری تعریف شد. يافته ها: در پژوهش حاضر داده های 795 بیمار بدون استفاده از فرم و 384 بیمار با استفاده از آن جمع آوری شد. ثبت کامل و دقیق داده ها در تمامی آیتم های مورد مطالعه در گروه استفاده کننده از چک لیست بیشتر بود (001/0>p). ثبت محل ضایعه بدون استفاده از فرم تنها در 8/20 درصد موارد به طور صحیح و کامل ثبت شد. این میزان با استفاده از فرم به 6/95 درصد افزایش یافت. همچنین ثبت کامل و دقیق برنامه تشخیصی از 9 درصد به 8/72 درصد و ثبت کامل و دقیق برنامه درمانی از 14 درصد به 7/68 درصد رسید. این بهبود در وضعیت ثبت داده بیماران در تمامی موارد معنی دار بود. نتيجه گيری: به نظر می رسد استفاده از چک لیست های از پیش طراحی شده در جمع آوری اطلاعات بالینی بیماران ترومایی، باعث بهبود چشمگیر ثبت داده ها و کیفیت شرح حال گیری می گردد

Awareness Level of Operating Room Nurses of Their Professional Tasks

Introduction: The awareness of the duties and responsibilities of operating rooms nurses is considered as a basis for systems monitoring and quality evaluation. Operating room nurses are supposed to be aware of their professional standards and achieve their functions following professional standards. Methods: This cross-sectional study was carried out based on the census and sampling with 143 operating room nurses working in nine training hospitals of Iran University of Medical Sciences. The research instrument was a researcher-made questionnaire, and the reliability was assessed through Cronbach's alpha. Also, both face and content validity of the questionnaire have been checked by faculty members. Data were analyzed by SPSS version 19 with descriptive statistics, Chi-square test, and Pearson's correlation coefficient. Results: In terms of preoperative responsibilities, 25.7%, 35.9%, and 38.3% of operating room nurses experienced the awareness levels of high, moderate, and weak, respectively. The awareness levels for 20.4%, 34.7%, and 44.9% of operating room nurses were evaluated as high, moderate, and weak, respectively. They were considering the post-operative responsibilities of operating room nurses, 32.3%, 32.3%, and 35.3% of operating room nurses who experienced the awareness levels of high, moderate, and weak, respectively. Conclusions: The results indicated that a vast majority of operating room nurses experienced a high level of awareness with respect to their responsibilities before, during, and after the operation. Nurses’ awareness of their mission, and management and official plans for promoting deficiencies in this regard could help promote health. Contextualized education on improving the quality of nursing services should be considered as a part of the training for OR nurses and suggested to investigate the awareness level of nurses and other treatment staff about the standards of their responsibilities in diverse sectors to perform suitable planning of tasks

Evolution of cardiac and renal impairment detected by high-field cardiovascular magnetic resonance in mice with renal artery stenosis

BACKGROUND: Renal artery stenosis (RAS) promotes hypertension and cardiac dysfunction. The 2-kidney, 1-clip mouse model in many ways resembles RAS in humans and is amenable for genetic manipulation, but difficult to evaluate noninvasively. We hypothesized that cardiovascular magnetic resonance (CMR) is capable of detecting progressive cardiac and renal dysfunction in mice with RAS and monitoring the progression of the disease longitudinally. METHODS: RAS was induced at baseline in eighteen mice by constricting the renal artery. Nine additional animals served as normal controls. CMR scans (16.4 T) were performed in all mice one week before and 2 and 4 weeks after baseline. Renal volumes and hemodynamics were assessed using 3D fast imaging with steady-state precession and arterial spin labelling, and cardiac function using CMR cine. Renal hypoxia was investigated using blood oxygen-level dependent (BOLD) MR. RESULTS: Two weeks after surgery, mean arterial pressure was elevated in RAS mice. The stenotic kidney (STK) showed atrophy, while the contra-lateral kidney (CLK) showed hypertrophy. Renal blood flow (RBF) and cortical oxygenation level declined in the STK but remained unchanged in CLK. Moreover, cardiac end-diastolic and stroke volumes decreased and myocardial mass increased. At 4 weeks, STK RBF remained declined and the STK cortex and medulla showed development of hypoxia. Additionally, BOLD detected a mild hypoxia in CLK cortex. Cardiac end-diastolic and stroke volumes remained reduced and left ventricular hypertrophy worsened. Left ventricular filling velocities (E/A) indicated progression of cardiac dysfunction towards restrictive filling. CONCLUSIONS: CMR detected longitudinal progression of cardiac and renal dysfunction in 2K, 1C mice. These observations support the use of high-field CMR to obtain useful information regarding chronic cardiac and renal dysfunction in small animals

On Quantum Simulation-Soundness

Non-interactive zero-knowledge (NIZK) proof systems are a cornerstone of modern cryptography, but their security has received little attention in the quantum settings. Motivated by improving our understanding of this fundamental primitive against quantum adversaries, we propose a new definition of security against quantum adversary. Specifically, we define the notion of quantum simulation soundness (SS-NIZK), that allows the adversary to access the simulator in superposition. We show a separation between post-quantum and quantum security of SS-NIZK, and prove that both Sahai’s construction for SS-NIZK (in the CRS model) and the Fiat-Shamir transformation (in the QROM) can be made quantumly-simulation-sound. As an immediate application of our new notion, we prove the security of the Naor-Yung paradigm in the quantum settings, with respect to a strong quantum IND-CCA security notion. This provides the quantum analogue of the classical dual key approach to prove the security of encryption schemes. Along the way, we introduce a new notion of quantum-query advantage functions, which may be used as a general framework to show classical/quantum separation for other cryptographic primitives, and it may be of independent interest

ERYTHROCYTE MEMBRANE FATTY ACIDS IN MULTIPLE SCLEROSIS PATIENTS AND HOT-NATURE DIETARY INTERVENTION WITH CO-SUPPLEMENTED HEMP-SEED AND EVENING-PRIMROSE OILS

The risk of developing multiple sclerosis (MS) is associated with increased dietary intake of saturated fatty acids. For many years it has been suspected that this disease might be associated with an imbalance between unsaturated and saturated fatty acids. We determined erythrocyte membrane fatty acids levels in Hot nature dietary intervention with co-supplemented hemp seed and evening primrose oils in multiple sclerosis patients. To determine the erythrocyte membrane fatty acids levels and correlate it with expanded disability status scale (EDSS) at baseline after 6 months intervention in MS patients by gas chromatography, in this double blind, randomized trial, 100 RRMS patients with EDS

Restoration of Mitochondrial Cardiolipin Attenuates Cardiac Damage in Swine Renovascular Hypertension

BACKGROUND: Renovascular hypertension (RVH) impairs cardiac structure and left ventricular (LV) function, but whether mitochondrial injury is implicated in RVH-induced myocardial damage and dysfunction has not been defined. We hypothesized that cardiac remodeling in swine RVH is partly attributable to cardiac mitochondrial injury. METHODS AND RESULTS: After 12 weeks of hypercholesterolemic (HC)-RVH or control (n=14 each), pigs were treated for another 4 weeks with vehicle or with the mitochondrial-targeted peptide (MTP), Bendavia (0.1 mg/kg subcutaneously, 5 days/week), which stabilizes mitochondrial inner-membrane cardiolipin (n=7 each). Cardiac function was subsequently assessed by multidetector-computed tomography and oxygenation by blood-oxygen-level-dependent magnetic resonance imaging. Cardiolipin content, mitochondrial biogenesis, as well as sarcoplasmic-reticulum calcium cycling, myocardial tissue injury, and coronary endothelial function were assessed ex vivo. Additionally, mitochondrial cardiolipin content, oxidative stress, and bioenergetics were assessed in rat cardiomyocytes incubated with tert-butyl hydroperoxide (tBHP) untreated or treated with MTP. Chronic mitoprotection in vivo restored cardiolipin content and mitochondrial biogenesis. Thapsigargin-sensitive sarcoplasmic reticulum Ca(2+)-ATPase activity that declined in HC-RVH normalized in MTP-treated pigs. Mitoprotection also improved LV relaxation (E/A ratio) and ameliorated cardiac hypertrophy, without affecting blood pressure or systolic function. Myocardial remodeling and coronary endothelial function improved only in MTP-treated pigs. In tBHP-treated cardiomyocytes, mitochondrial targeting attenuated a fall in cardiolipin content and bioenergetics. CONCLUSIONS: Chronic mitoprotection blunted myocardial hypertrophy, improved LV relaxation, and attenuated myocardial cellular and microvascular remodeling, despite sustained HC-RVH, suggesting that mitochondrial injury partly contributes to hypertensive cardiomyopathy