1,220 research outputs found
Tsallis holographic dark energy in the Brans-Dicke cosmology
Using the Tsallis generalized entropy, holographic hypothesis and also
considering the Hubble horizon as the IR cutoff, we build a holographic model
for dark energy and study its cosmological consequences in the Brans-Dicke
framework. At first, we focus on a non-interacting universe, and thereinafter,
we study the results of considering a sign-changeable interaction between the
dark sectors of the cosmos. Our investigations show that, compared with the
flat case, the power and freedom of the model in describing the cosmic
evolution is significantly increased in the presence of the curvature. The
stability analysis also indicates that, independent of the universe curvature,
both the interacting and non-interacting cases are classically unstable. In
fact, both the classical stability criterion and an acceptable behavior for the
cosmos quantities, including the deceleration and density parameters as well as
the equation of state, are not simultaneously obtainable.Comment: Accepted version, Eur. Phys. J. C (2018
Antibacterial activity of the brown algae (Sargassum glaucescens) ethanolic and aqueous extracts from Chabahar coasts, Oman Sea, Iran
The widespread uses of antibiotics have been resulted in resistant strains of microorganisms and increasing of worldwide antibiotic resistance. Thus the investigations on new natural antibacterial agents as new drugs are important. According to the previous researches, some multicellular marine algae have significant antibacterial properties. In the present study, antibacterial effects of organic and aqueous extracts of Sargassum glaucescens (collected from Chabahar’s coast, Oman Sea, Iran) were tested on three strains of Gram-negative bacteria: E. coli, Proteus vulgaris, Vibrio cholerae and two strains of Gram-positive bacteria: Listeria monocytogenes and Staphylococcus aureus. Extractions were obtained by immersion method after 48 hours. Antibacterial effects were investigated by the disk diffusion method and serial dilutions in tube to determine the minimum inhibitory concentration. The ethanolic extract showed the largest impact on the L. monocytogenes with significant difference than that by the neomycin. Yet, the aqueous extract showed no effects. Ethanolic extract of algae had no effects on the Proteus vulgaris. The results of present study demonstrated that Ethanolic extract of S. glaucescens had reliable antibacterial effects against L. monocytogenes, Vibrio cholerae, E. coli and Staphylococcus aureus
Combining mammaglobin and carcinoembryonic mRNA markers for early detection of micrometastases from breast cancers - a molecular study of 59 patients
Introduction: As many as 30% of node-negative breast cancer patients relapse within five years, suggesting that current histological detection methods are inadequate for identifying metastatic disease. Detecting small number of cancer cells in the breast tissue or lymph node by reverse transcription-polymerase chain reaction (RT-PCR) assays using a combination of tissue and cancer specific markers might be very useful in the early detection or monitoring of the treatment. Mammaglobin is a member of the uteroglobin gene family and appears to be expressed only in breast tissue. Carcinoembryonic antigen has been the preferred molecular marker for detection of micro metastases in lymph nodes in almost all carcinomas. Materials and Methods: Samples were collected from randomly chosen breast cancer patients undergoing modified mastectomy or breast conserving surgery between September 2003 and July 2004. RT-PCR was applied to study the expression of MMG and CEA markers. Breast cancer micrometastases in axillary lymph nodes were also assessed. Results: The MMG marker was positive in 9/10 normal breast tissues, 3/ 3 breast fibroadenomas and 37/39 of breast carcinoma tissues, giving an overall sensitivity of 94%. The sensitivity was 80% for metastatic lymph node samples. On the other hand CEA showed 95% sensitivity for malignant breast tumors and 100% sensitivity for metastatic lymph nodes. Conclusions: RT-PCR using a combination of MMG and CEA markers is a powerful tool to complement current routine histopathology techniques for detection of breast cancer metastasis in axillary nodes
Prevalence of human papillomavirus genotypes in women with normal and abnormal cervical cytology in Iran
Introduction: HPV infection has a prime etiologic role in development and progression of cervical cancer, one of the most frequent forms of cancer among women in developing countries. This study was designed to determine the most prevalent HPV genotypes in women with normal and abnormal cervical cytology in Iran. Materials and Methods: Samples from134 patients, including 127 who attended gynecology clinics and 7 with solid cervical tumors were used. All 127 patients underwent routine Pap tests for cytological evaluation and at the same visit a sample of cervical epithelial cells was obtained by scraping the cervix osteum. In each case HPV infection was primarily evaluated by PCR using GP 5/6 primers and then subtyping was performed in proved infected samples with specific primers for HPV 16, 18, 31, 33, 11 and 6. After cytological evaluation, 50 patients with abnormal Pap tests were categorized as the abnormal group and the remaining 77 patients as the normal group. Results: In the normal group, HPV infection was established in 10 cases (13% infection rate), while 30 HPV positive cases were discovered in the abnormal group (60% infected). The most prevalent genotypes among the infected samples were HPV 16 (76%), HPV18 (12.7%) and HPV11/6 (8.5%). Moreover, all 7 tumor samples were positive for HPV general primers of which, 5 samples were infected with HPV 16, two were co-infected with HPV16,18 and HPV16,31 genotypes and one was infected with HPV 18. Conclusions: Infection with HPV 16 was found to be significantly higher in abnormal group in comparison with normal group (42% vs. 11.6%, P value <0.005), likewise HPV18 genotypes were proved to be more prevalent in abnormal group (8% vs. 0%, P value <0.05). No significant relation between other HPV genotypes and pathologic cervical changes was obtained. According to our study high rates of infection with HPV genotypes in sexually active Iranian women makes molecular investigation for HPV16 and 18 very essential in clinical approaches to patients with proven dysplasia in their screening tests and also for those patients with borderline (i.e. ASCUS) or incongruous pathology reports. Larger studies are required to determine the most appropriate vaccine with highest protection in Iranian women
Seroprevalence of human T-cell lymphotropic virus type 1 infection (HTLV1) in different patients in the north of Iran
Human T-cell lymphotropic virus type-1 (HTLV1) is a lymphotropic virus which can contribute to carcinogenesis in adult T-cell leukemia, myleopathy and other disorders. 20 million people are affected by this virus in the world. The aim of this study was to determine the incidence of human T-cell lymph tropic virus type 1 infection in patients referred to Emam’s hospital laboratory in Sari. A cross-sectional study was done in 2009 to 2010 based on the different patients that were referred to Emam`s hospital laboratory in Sari. Our samples were selected by simple random selection, after venous blood sample was centrifuged and reserved in -70°C. All the samples were tested by enzyme-linked immuno sorbent assay (ELISA). An ELISA positive result was checked by Western blot (WB) assays. Out of 1200 cases, 776 were female (65%) with ages between 1 and 76 years old. Most of the cases were Mazandaranian (99%); although only one person was recorded as HTLV1 positive (0.08%). He was a 41 years old man, living in Sari, with high school education. He was married (one wife) without any risk factor in past medical history, such as surgery, transfusion and abuse of injection, but he had HBV infection. Most of the females were housewives and most of the males were non-governmental employees; moreover, diabetes was more common among them. The results of the samples show that 122 women were pregnant, 92 cases had transfusion and 642 cases had different surgery. It was observed that the incidence of HTLV1 infection was very rare in the north of Iran (Sari); therefore, the routine HTLV1 screening was not recommended.Key words: Seroprevalence, human T-cell lymphotropic virus type-1 (HTLV1), patients, Iran
An Audio-visual Solution to Sound Source Localization and Tracking with Applications to HRI
Robot audition is an emerging and growing branch in the robotic community and is necessary for a natural Human-Robot Interaction (HRI). In this paper, we propose a framework that integrates advances from Simultaneous Localization And Mapping (SLAM), bearing-only target tracking, and robot audition techniques into a unifed system for sound source identification, localization, and tracking. In indoors, acoustic observations are often highly noisy and corrupted due to reverberations, the robot ego-motion and background noise, and possible discontinuous nature of them. Therefore, in everyday interaction scenarios, the system requires accommodating for outliers, robust data association, and appropriate management of the landmarks, i.e. sound sources. We solve the robot self-localization and environment representation problems using an RGB-D SLAM algorithm, and sound source localization and tracking using recursive Bayesian estimation in the form of the extended Kalman Filter with unknown data associations and an unknown number of landmarks. The experimental results show that the proposed system performs well in the medium-sized cluttered indoor environment
Exploration in Information Distribution Maps
In this paper, a novel solution for autonomous robotic exploration is proposed. The distribution of information in an unknown environment is modeled as an unsteady diffusion process, which can be an appropriate mathematical formulation and analogy for expanding, time-varying, and dynamic environments. This information distribution map is the solution of the diffusion process partial differential equation, and is regressed from sensor data as a Gaussian Process. Optimization of the process parameters leads to an optimal frontier map which describes regions of interest for further exploration. Since the presented approach considers a continuous model of the environment, it can be used to plan smooth exploration paths exploiting the structural dependencies of the environment whilst handling sparse sensors measurements. The performance of the proposed approach is evaluated through simulation results in the well-known Freiburg and Cave maps
Information-based view initialization in visual SLAM with a single omnidirectional camera
© 2015 Elsevier B.V. All rights reserved. This paper presents a novel mechanism to initiate new views within the map building process for an EKF-based visual SLAM (Simultaneous Localization and Mapping) approach using omnidirectional images. In presence of non-linearities, the EKF is very likely to compromise the final estimation. Particularly, the omnidirectional observation model induces non-linear errors, thus it becomes a potential source of uncertainty. To deal with this issue we propose a novel mechanism for view initialization which accounts for information gain and losses more efficiently. The main outcome of this contribution is the reduction of the map uncertainty and thus the higher consistency of the final estimation. Its basis relies on a Gaussian Process to infer an information distribution model from sensor data. This model represents feature points existence probabilities and their information content analysis leads to the proposed view initialization scheme. To demonstrate the suitability and effectiveness of the approach we present a series of real data experiments conducted with a robot equipped with a camera sensor and map model solely based on omnidirectional views. The results reveal a beneficial reduction on the uncertainty but also on the error in the pose and the map estimate
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