69 research outputs found
Corporate Life Cycle and the Explanatory Power of Risk Measures versus Performance Measures
The major aim of this paper is to compare the explanatory power of risk measures versus performance measures in different life-cycle stages. To test the hypotheses, first, sample firms were classified into three life-cycle stages (Growth, Mature and Decline). Then, using regression models and Vuong's Z-statistic, the hypotheses were investigated. In this study, financial information of 75 firms which were accepted at Tehran’s Stock Exchange (TSE) from 2003 to 2008 (450 firm-years) was examined. The results of this study show that in growth and decline stages, the explanatory power of risk measures is significantly higher than performance measures and in mature stage, the opposite is true
Performance Evaluation of Intelligent Adaptive Traffic Control Systems: A Case Study
ABSTRACT Mashhad, the second largest city in Iran, like many other big cities, is faced with increasing traffic congestion owing to rapidly increasing population and annual pilgrimage. In recent years, Mashhad traffic and transportation authorities have been challenged with how to manage the increasing congestion with limited budgets for major roadway construction projects. Mashhad has recognized the need to improve the existing system capacity to get the most out of their current transportation system infrastructures. Since most of the delay times occur at signalized intersections, using an intelligent control system with proper capabilities to overcome the growing traffic requirements is recommended. Following comprehensive studies carried out with the aim of developing the Mashhad traffic control center, the SCATS adaptive traffic control system was introduced as the selected intelligent control system for integrating signalized intersections. The first intersection was equipped with this system in 2005. This paper describes the results of a field evaluation in which fixed actuated-coordinated signal timings are compared with those dynamically computed by SCATS. The effects of this system on optimizing fuel consumption as well as reducing air pollutants are fully discussed. It is found that SCATS consistently reduced travel times and the average delay per stopped or approaching vehicle. The positive impact of adaptive traffic control systems on fuel consumption and air pollution are also highlighted
Formulation of Menthol-Loaded Nanostructured Lipid Carriers to Enhance Its Antimicrobial Activity for Food Preservation
Purpose: Due to the
antimicrobial property, menthol have significant potential for food
preservation and foodstuff shelf life improvement. Nevertheless, menthol
instability, insolubility, and rapid crystallization in aqueous media make it
unsuitable for used in food products. This work was aimed to prepare
menthol-loaded nanostructured lipid carriers (NLCs) to enhance its
antimicrobial activity.
Methods: Morphology,
particle size and size distribution, encapsulation efficiency percent (EE%),
and physical stability of the optimized formulation, prepared by hot melt
homogenization method, were characterized by scanning electron microscopy,
particle size analyzing, gas chromatography, and X-ray diffraction (XRD)
methods. Minimum inhibitory concentration and minimum bactericidal
concentration of menthol-loaded NLCs were evaluated and compared with
conventional menthol emulsion against various Gram-positive (Staphylococcus
aureus, Bacillus cereus) and Gram-negative bacteria (Escherichia coli),
as well as one fungus (Candida albicans).
Results: Menthol-loaded
NLCs were spherically shaped nanosized (115.6 nm) particles with narrow size
distribution (PDI = 0.2), suitable menthol EE% (98.73%), and appropriate
physical stability after 90 days of storage period. XRD results indicated that
menthol was in the amorphous form in the nanoparticles matrix. Antibacterial
assay results revealed that the menthol-loaded NLCs exhibited significantly
higher in vitro antimicrobial property than conventional menthol
emulsion. The results also indicated that menthol-loaded NLCs had better effect
on fungi than bacteria, and furthermore, antibacterial efficiency on
Gram-positive bacteria was higher than Gram-negative bacteria.
Conclusion: In conclusion,
NLCs could be a promising carrier for improvement of antimicrobial activity and
preservation efficacy of essential oils in foodstuffs
EXTENDED-SPECTRUM BETA-LACTAMASE PRODUCING GRAM NEGATIVE BACTERIA IN IRAN
Background: The emergence and spread of extended spectrum β-lactamase (ESBL)-producing Gram- negative bacteria
(GNB), particularly in Enterobacteriaceae, Acinetobacter baumannii, and Pseudomonas aeruginosa, have increased all over
the world. ESBLs are characterized by their ability to hydrolyze β-lactams, early cephalosporins, oxyimino-thiazolyl
cephalosporins, and monobactams, but not cephamycins or carbapenems. The rate of nosocomial infections caused by
ESBL-producing GNB in Asia Pacific has increased and several studies have identified their prevalence in the region. The
aim of this study is to review the prevalence of ESBL-producing GNB in the West Asia and the Middle East with a
particular focus on Iran.
Materials and Methods: The available evidence from various studies (Microbia and clinical studies, retrieved from the
PubMed, and Scopus databases) regarding the ESBL producing Gram negative bacteria in Iran were evaluated.
Results: In almost all parts of the country, high resistance has been observed, especially in the central part of Iran. Up to
89.8% Escherichia coli, 72.1% Klebsiella pneumonia, 84.2% Acinetobacter baumannii, and 83.8% Pseudomonas
aeruginosa isolates are ESBL positive.
Conclusion: The present study showed the increasing prevalence of ESBLs in different regions of Iran, which could be
useful to strategic policy towards reducing reduce their prevalence
Workforce and Employment Status of Sleep Medicine Graduates in Iran
Background and Objective: Sleep medicine is a multidisciplinary specialty that focuses on diagnosing and treating sleep disorders. Sleep medicine fellowship programs in Iran commenced in 2012 at Tehran University of Medical Sciences, Tehran, Iran. This study aimed to investigate the human resources and employment status of sleep medicine fellowship graduates in Iran.
Materials and Methods: This study was a descriptive cross-sectional study conducted in Iran in 2022 using conven-ience sampling and included 41 sleep medicine fellows in Iran. Data collection tools included a demographic question-naire and a researcher-made survey. Data were analyzed using the SPSS software.
Results: Out of 57 sleep medicine fellows, 41 individuals with an average age of 44.95 ± 7.57 years participated in the study. Only 12% of the fellows were satisfied with their income, and all participants expressed dissatisfaction with their insurance coverage. 92% considered the existence of a national guideline for sleep medicine to be crucial, while 66.7% felt the curriculum of medical sleep medicine had some deficiencies.
Conclusion: Lack of a suitable national guideline for treating and preventing sleep disorders, lack of insurance coverage for tests and respiratory assist devices, and high costs of establishing and equipping specialized sleep clinics are major challenges recognized by sleep medicine fellows. Additionally, due to the low priority given to these diseases by authorities and the inappropriate distribution of sleep medicine specialists in the country, access to appropriate treatment for sleep disorders is only feasible in giant cities
Exosomes from Adipose Tissue-derived Mesenchymal Stem Cells Induce Regulatory T Cells in COVID‐19 Patients
An imbalance between regulatory T (Treg) and T-helper (Th)-17 cells has been implicated in the pathogenesis of coronavirus disease 2019 (COVID-19). Mesenchymal stem cells (MSCs) exert immunomodulatory properties through secreting exosomes. This study aimed to assess the effect of MSC-derived exosomes (MSC-Exo) on the differentiation of peripheral blood mononuclear cells (PBMCs) into Tregs from patients with COVID-19.
Exosomes were isolated from adipose tissue–derived MSCs. PBMCs were separated from the whole blood of COVID-19 patients (n=20). Treg frequency was assessed before and 48 hours after treatment of PBMCs with MSC-Exo using flow cytometry. Expression of FOXP3 and cytokine genes, and the concentration of cytokines associated with Tregs, were assessed before and after treatment with MSC-Exo.
The frequency of CD4+CD25+CD127- Tregs was significantly higher after treating PBMCs with MSC-Exo (6.695±2.528) compared to before treatment (4.981±2.068). The expressions of transforming growth factor (TGF)-β1, interleukin (IL)-10, and FOXP3 were significantly upregulated in MSC-Exo–treated PBMCs. The concentration of IL‐10 increased significantly after treatment (994.7±543.9 pg/mL) of PBMCs with MSC-Exo compared with before treatment (563.5±408.6 pg/mL). The concentration of TGF-β was significantly higher in the supernatant of PBMCs after treatment with MSC-Exo (477.0±391.1 pg/mL) than PBMCs before treatment (257.7±226.3 pg/mL).
MSC-Exo has the potential to raise anti-inflammatory responses by induction of Tregs, potentiating its therapeutic effects in COVID-19
A multi-targeted approach to suppress tumor-promoting inflammation
Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes
Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017
A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic
Global, regional, and national burden of colorectal cancer and its risk factors, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019
Funding: F Carvalho and E Fernandes acknowledge support from Fundação para a Ciência e a Tecnologia, I.P. (FCT), in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy i4HB; FCT/MCTES through the project UIDB/50006/2020. J Conde acknowledges the European Research Council Starting Grant (ERC-StG-2019-848325). V M Costa acknowledges the grant SFRH/BHD/110001/2015, received by Portuguese national funds through Fundação para a Ciência e Tecnologia (FCT), IP, under the Norma Transitória DL57/2016/CP1334/CT0006.proofepub_ahead_of_prin
Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND: Disorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021. METHODS: We estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined. FINDINGS: Globally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer. INTERPRETATION: As the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed
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