149 research outputs found

    Analysis of the lactose metabolism in E. coli using sum-of-squares decomposition

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    We provide a system-theoretic analysis of the mathematical model of lactose induction in E.coli which predicts the level of lactose induction into the cell for specified values of external lactose. Depending on the levels of external lactose and other parameters, the Lac operon is known to have a low steady state in which it is said to be turned off and high steady state where it is said to be turned on. Furthermore, the model has been shown experimentally to exhibit a bi-stable behavior. Using ideas from Lyapunov stability theory and sum-of-squares decomposition, we characterize the reachable state space for different sets of initial conditions, calculating estimates of the regions of attraction of the biologically relevant equilibria of this system. The changes in the basins of attraction with changes in model parameters can be used to provide biological insight. Specifically, we explain the crucial role played by a small basal transcription rate in the Lac operon. We show that if the basal rate is below a threshold, the region of attraction of the low steady state grows significantly, indicating that system is trapped in the (off) mode, showing the importance of the basal rate of transcription

    Imaging techniques for ocular neoplasia

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    Background: Novel ocular imaging modalities have greatly impacted the diagnosis and management of different types of ocular neoplasia. In this narrative review, we summarize the practical features of popular and novel imaging modalities for ocular tumors. Methods: Four databases, including PubMed/MEDLINE, Web of Science, Scopus, and Google Scholar, were searched from January 1, 2000 to August 31, 2022. Articles reporting different imaging modalities for diagnosing or monitoring treatment responses of ocular tumors were extracted using various combinations of the following keywords: ocular neoplasia, positron emission tomography or PET, single-photon emission computed tomography or SPECT, optical coherence tomography or OCT, OCT angiography or OCTA, computed tomography or CT, ultrasonography or US, ultrasound biomicroscopy or UBM, and magnetic resonance imaging or MRI. Results: Various ocular imaging modalities had different accuracies as adjunctive tools for detecting or managing ocular tumors. Anterior ultra-high-resolution optical coherence tomography (OCT) could be used to evaluate images with < 5-µm resolution. OCT angiography provided deeper insight into retinal vascular changes associated with the malignant transformation of choroidal melanoma. OCT in children altered the diagnosis of suspicious retinoblastoma in 3% of the cases and treatment plan in 11% of the cases. While positron-emission tomography (PET)/computed tomography (CT) allowed the detection of metastatic lesions of choroidal melanoma by full-body scanning, single-photon emission CT was more sensitive compared to PET in detecting choroidal melanoma. Ultrasound biomicroscopy, with an accuracy exceeding 92.5%, could detect retinal calcification in lesions measuring 2–3 mm. Magnetic resonance imaging (MRI) had better contrast compared to ultrasound biomicroscopy and higher sensitivity compared to CT in detecting post-laminar optic nerve invasion. However, MRI had a lower spatial resolution compared to OCT. Further development of imaging modalities and their application in drug development would improve the treatment of ocular tumors. Conclusions: Although diagnosing ocular tumors depend on clinical characteristics, innovations in ocular imaging have enabled early diagnosis and timely, appropriate management of ocular neoplasia, which are conducive to favorable visual outcomes and increased life expectancy. Further systematic reviews and meta-analyses of primary studies focusing on a specific imaging modality in ocular neoplasia could precisely determine the diagnostic accuracy of each imaging modality to better guide eye practitioners with efficient diagnostic or therapeutic approaches for these sight- or life-threatening entities. Imaging modalities may play a major role in drug development in the future

    The knowledge, attitude, and action of Northern Iranian women about cervical cancer and screening

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    Background: Cervical cancer is one of the most prevalent cancers in the world among women which its early diagnosis plays an important role in the prognosis. There are many factors that contribute to the participation in the screening programs, most notably the level of knowledge and attitude of people towards cancer. Understanding the level of these factors in the female population and its association with participation in screening programs is important. Therefore, the aim of this study was to determine the knowledge, attitude and practice of women in the north of Iran to compare these factors between two groups with different baseline knowledge.Methods: This cross-sectional study was carried out among female medical clients and healthcare staff in a healthcare center in the north of Iran. All the eligible patients were interviewed and were asked to fill a questionnaire containing the demographic data, knowledge, attitude, and action about cervical cancer and screening. The data were analyzed by SPSS v24.Results: A total of 283 females entered our study of which 156(55.1%) were clients of the healthcare center and 127(44.9%) were non-physician healthcare staff. Ninety (60.8%) of clients and 39(56.5%) of the staff have performed pap smear at least once (p=0.556). The levels of knowledge and attitude were significantly lower in the clients (p < 0.001 and p=0.003, respectively). There were no significant differences regarding the level of knowledge and attitude between those who performed pap smear and those who did not (0.621 and 0.788, respectively).Conclusions: Increasing awareness, especially improving attitudes in the female population, should be the focus of the health care system to encourage more women to participate in screening programs

    Behavioral Mimicry Covert Communication

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    Covert communication refers to the process of communicating data through a channel that is neither designed, nor intended to transfer information. Traditionally, covert channels are considered as security threats in computer systems and a great deal of attention has been given to countermeasures for covert communication schemes. The evolution of computer networks led the communication community to revisit the concept of covert communication not only as a security threat but also as an alternative way of providing security and privacy to communication networks. In fact, the heterogeneous structure of computer networks and the diversity of communication protocols provide an appealing setting for covert channels. This dissertation is an exploration on a novel design methodology for undetectable and robust covert channels in communication networks. Our new design methodology is based on the concept of behavioral mimicry in computer systems. The objective is to design a covert transmitter that has enough degrees of freedom to behave like an ordinary transmitter and react normally to unpredictable network events, yet it has the ability to modulate a covert message over its behavioral fingerprints in the network. To this end, we argue that the inherent randomness in communication protocols and network environments is the key in finding the proper medium for network covert channels. We present a few examples on how random behaviors in communication protocols lead to discovery of suitable shared resources for covert channels. The proposed design methodology is tested on two new covert communication schemes, one is designed for wireless networks and the other one is optimized for public communication networks (e.g., Internet). Each design is accompanied by a comprehensive analysis from undetectability, achievable covert rate and reliability perspectives. In particular, we introduced turbo covert channels, a family of extremely robust model-based timing covert channels that achieve provable polynomial undetectability in public communication networks. This means that the covert channel is undetectable against any polynomial-time statistical test that analyzes samples of the covert traffic and the legitimate traffic of the network. Target applications for the proposed covert communication schemes are discussed including detailed practical scenarios in which the proposed channels can be implemented

    Values of Urinary Mineral Excretion in Healthy Iranian Children

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    Introduction: Normal values of urinary mineral excretion differ in different geographic parts. The aim of this study was to determine age-related reference intervals for urinary minerals in healthy children in the south-west of Iran. Materials and Methods: Midstream non-fasting urine samples were collected and the amount of calcium, oxalate, uric acid, phosphate, magnesium, citrate, and creatinine was measured in all urine samples. The urinary mineral concentrations were reported as mineral to creatinine ratios (mg/mg). Data were analyzed by SPSS software version 16 and independent t-test and T-Hoteling test was used.Results: The study involved 232 children aged 7 to 10 years. The 5th and 95th percentile values of urinary minerals to creatinine ratios were determined. The mean urinary Ca/Cr ratio was 0.14± 0.18 with a 95th percentile value of 0.295. For oxalate to creatinine ratio, the mean value was 0.068± 0.09 mg/mg with a 95th percentile value of 0.23. The mean uric acid to creatinine ratio was 0.358±0.211 mg/mg with an upper 95th percentile value of 0.69 and the mean Ph/Cr ratio was 0.439 and the 95th percentile was 1.01 mg/mg. Conclusions: We found out that the normal values of random urinary mineral to creatinine ratio differ in our region from the other countries and even from the other regions in Iran. We concluded that child's age and ethnicity should be taken into consideration when assessing the urinary mineral to creatinine ratio.Keywords: Urine Specimen Collection; Urine minerals; Child; Iran; Calcium; Oxalate; Citrate; Uric Acid; Phosphate

    Herbal Medicine in the Management of Tinnitus

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    Tinnitus, which is commonly defined as “ringing in the ears” by the patients, is a perception of an auditory sensation without any accompanying external stimulation. It accounts for a notable part of visits in otolaryngology clinics and has been estimated to involve about 5–15% of adult population making serious problems in 3–5% of patients. Tinnitus causes a lot of problems for patients, their family, and guardians and significantly decreases quality of life of patients. Many treatment methods have been proposed and presented for Tinnitus since the first year of diagnosis. These methods range from conservative management and chemical medications to surgical methods. As the other diseases and conditions, herbal medicine has been trying to treat Tinnitus and a variety of medications have been proposed. In this chapter, we aimed to have a comprehensive review on the current herbal medications of Tinnitus from all over the world

    Comparison of the Voiding Cystourethrogram Results One and Three weeks after the First Urinary Tract Infection in 1-Month to 15-Year-Old Children

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    Introduction: To determine whether the timing of voiding cystoureterogram (VCUG) in the first or the third week after a diagnosis of urinary tract infection (UTI) is important in the diagnosis and severity of VUR.Materials and Methods: In this case-control study, 72 children between 1 month and 15 years old diagnosed with their first episode of UTI were investigated over one year. The study population was divided into 2 groups of 36, early (VCUG in the first week after UTI) and late (VCUG 3 weeks after UTI), and compared the severity and incidence of reflux in both groups.Results: The prevalence of VUR was 66.6%. Twenty-two cases in the first group (61%) and 26 cases in the second group (72.2%) presented with VUR. The peak age of the disease in both groups was 1-3 years with a female predominance. The most common germ detected was E-Coli and the most common presentations were fever (87.5%) and dysuria (26.3%).Conclusions: As VUR following UTI is very common in children and is one of the most important risk factors of early hypertension and chronic renal failure, early diagnosis by VCUG seems to be useful in all UTI patients before discharge. Keywords: Urinary Tract Infection; Vesico-Ureteral Reflux; VCUG; Child

    A phase III, randomized, two-armed, double-blind, parallel, active controlled, and non-inferiority clinical trial to compare efficacy and safety of biosimilar adalimumab (CinnoRA (R)) to the reference product (Humira (R)) in patients with active rheumatoid arthritis

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    Background: This study aimed to compare efficacy and safety of test-adalimumab (CinnoRA (R), CinnaGen, Iran) to the innovator product (Humira (R), AbbVie, USA) in adult patients with active rheumatoid arthritis (RA). Methods: In this randomized, double-blind, active-controlled, non-inferiority trial, a total of 136 patients with active RA were randomized to receive 40 mg subcutaneous injections of either CinnoRA (R) or Humira (R) every other week, while receiving methotrexate (15 mg/week), folic acid (1 mg/day), and prednisolone (7.5 mg/day) over a period of 24 weeks. Physical examinations, vital sign evaluations, and laboratory tests were conducted in patients at baseline and at 12-week and 24-week visits. The primary endpoint in this study was the proportion of patients achieving moderate and good disease activity score in 28 joints-erythrocyte sedimentation rate (DAS28-ESR)-based European League Against Rheumatism (EULAR) response. The secondary endpoints were the proportion of patients achieving American College of Rheumatology (ACR) criteria for 20% (ACR20), 50% (ACR50), and 70% (ACR70) responses along with the disability index of health assessment questionnaire (HAQ), and safety. Results: Patients who were randomized to CinnoRA (R) or Humira (R) arms had comparable demographic information, laboratory results, and disease characteristics at baseline. The proportion of patients achieving good and moderate EULAR responses in the CinnoRA (R) group was non-inferior to the Humira (R) group at 12 and 24 weeks based on both intention-to-treat (ITT) and per-protocol (PP) populations (all p values >0.05). No significant difference was noted in the proportion of patients attaining ACR20, ACR50, and ACR70 responses in the CinnoRA (R) and Humira (R) groups (all p values >0.05). Further, the difference in HAQ scores and safety outcome measures between treatment arms was not statistically significant. Conclusion: CinnoRA (R) was shown to be non-inferior to Humira (R) in terms of efficacy at week 24 with a comparable safety profile to the reference product

    Family clustering of SARS-CoV-2 in Qazvin, Northwest of Iran

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    Background: Human infection affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been recognized as a global health concern. We report the epidemiological and clinical characteristics of patients with a familial cluster from Qazvin province (located in the northwest of Iran). f SARS-CoV-2 Methods: In this cross-sectional study, we enrolled 332 hospitalized patients that were confirmed SARS-CoV-2 diseases with laboratory-based (PT-PCR) test in Qazvin p ovince, Iran. Having family infection transmission and subsequently, family clustering of SARS-COV-2 disease was assessed with the Generalized Estimating Equation model in patients. Results: Crude odds ratio estimates of creating family clustering of SARS-CoV-2 infection was 0. 47 times [95% CI: 0.23, 0.98, p=0.045] less for female compared to the males; 2.26 [95% CI: 1.11, 4.58, p=0.024] and 2.69 [95% CI: 1.47, 4.93, p=0.001] for SARS-CoV-2 patients that had digestive and muscle pain in comparison with those did not this mentioned symptoms, respectively. 1.52 [95% CI: 1.05, 2.23, p=0.024] for pa ients with a longer hospitalization compar d with patients that had shorter duration of hospitalization and adjusted odds ratio estimates were 2.13 [95% CI: 1.12, 4.03, p=0.020] for patients who receive public health services in comparison those did not receive public health services. Conclusion: Our findings confirm the person-to-person transmission of this novel coronavirus in family settings and hospitals, and the reports of infected travelers in other geographical regions. Major gaps in our knowledge about the potential factors in creating family clustering of SARS-CoV-2 infection, epidemiology, duration of human transmission and etc. need fulfillment by future studies. Keywords: Epidemiology, SARS-CoV-2, COVID-19, Family Clustering, Close Contact , Ira
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