Implementation of secure email server in cloud environment

In the recent virtual communication world, the email services play a vital role as a basic content of heterogeneous networking infrastructure. Whereby, multiple platforms are connecting each other. Mail Server refers to computer performing Mail Transfer Agent functions. MTA is software that delivers electronic mail messages from one computer to another, by using client-server application architecture. MTA implements both sender and receiver portions of SMTP (Simple Mail Transfer Protocol). Postfix is a free and open-source MTA which is fast, easy-to-administrator and provide secure communication over Internet. In this paper we focus on the problem of email contents disclosure, and establish a secure mail server by using Postfix in Linux platform and then implement it into a cloud service provider as IaaS (Infrastructure as a Service). Security is provided by tuning a Transport Layer Security (TLS), and SMTP-AUTH which use Simple Authentication and Security Layer (SASL) as a security mechanism and platform

Role of oxygen concentration in the osteoblasts behavior: A finite element model

Oxygen concentration plays a key role in cell survival and viability. Besides, it has important effects on essential cellular biological processes such as cell migration, differentiation, proliferation and apoptosis. Therefore, the prediction of the cellular response to the alterations of the oxygen concentration can help significantly in the advances of cell culture research. Here, we present a 3D computational mechanotactic model to simulate all the previously mentioned cell processes under different oxygen concentrations. With this model, three cases have been studied. Starting with mesenchymal stem cells within an extracellular matrix with mechanical properties suitable for its differentiation into osteoblasts, and under different oxygen conditions to evaluate their behavior under normoxia, hypoxia and anoxia. The obtained results, which are consistent with the experimental observations, indicate that cells tend to migrate toward zones with higher oxygen concentration where they accelerate their differentiation and proliferation. This technique can be employed to control cell migration toward fracture zones to accelerate the healing process. Besides, as expected, to avoid cell apoptosis under conditions of anoxia and to avoid the inhibition of the differentiation and proliferation processes under conditions of hypoxia, the state of normoxia should be maintained throughout the entire cell-culture process

Energy-efficient intrusion detection in wireless sensor network

The use of Wireless Sensor Networks (WSNs) has developed rapidly in the last decade. Deploying tiny sensors with limited battery power in open and unprotected environment and dynamic topology in WSNs raises security issues in this kind of networks. Attacks can occur from any direction and any node in WSNs, so one crucial security challenge is to detect networks' intrusion. There are several algorithms for building Intrusion Detection Systems (IDS) based on different WSN routing protocol classifications with respect to energy-efficient manner. This paper provides an overview of the research on IDS in WSNs, focusing on routing protocol classification depending on network structure with respect to energy consumption as a crucial parameter in these kinds of networks. In addition, some simulation manners are reviewed

Investigation the Shigella serotypes invasive cells isolated from patients with diarrhea in HEp-2 cell culture

Background and aims: Diarrhea is one of the most prevalent cause of children`s death in developing countries. Gastrointestinal diseases are the cause of much death among the children under the age of 5 every year. In this study the invasiveness character of Shigella strains was investigated by HEp-2cell cell culture technique. Methods: In this descriptive study, 280 rectal swabs (140 with dysentery and 140 watery diarrhea) from patients suffering from diarrhea before using any antibiotic and 140 from healthy people as control group were collected. These specimens were cultured in Hektoen and XLD agar as selective and differential media, then after 24 hours incubation in 37˚C their morphology were studied and finally the isolates were confirmed with biochemical tests. Shigella spp strains consist of 20 collection strains were used for consideration of invasiveness in Shigella. Antibiotic typing also performed according to CLSI instructions. Results: Thirty six strains of Shigella (8.6%) were isolated from thesamples under the study. Most strains isolated from patients, were Shigella flexneri isolated with 16. Our study on HEp-2 cell cultures showed that only 14 (9 isolates, 5 collections) had invasive properties of Shigella strains. Conclusion: The results show that firstly all Shigella isolates are not capable of invading intestinal epithelial cells Secondly invasion is not a constant attitude and it would not go away by tim

Evaluation du risque de rupture d'un anévrisme de l'aorte thoracique ascendante en fonction de la rigidité artérielle locale

A methodology named local extensional stiffness identification (LESI) was developed to identify in vivo local extensional stiffness non-invasively in patients suffering from ascending thoracic aortic aneurysm (ATAA). An aneurysm is a ballooning of an artery, which can burst and lead to life threatening hemorrhage. For the thoracic aorta, a diameter greater than 5.5 cm is generally considered aneurysmal, and surgical intervention is recommended. The diameter as current risk indicator causes very high rate of misprogrammed surgical interventions. It this thesis it is suggested to assist physicians in taking the correct decision by considering biomechanical factors such as in vivo material properties of the tissue as we previously showed that there is a significant correlation between a stretch based rupture criterion of the ATAA and the local ex-tensional stiffness of the aorta. Gated computed tomography (CT) scans and brachial pressures were used to assess the risk of rupture of ATAAs. Using these images, we apply the LESI method for 11 patients to first reconstruct the strain throughout the cardiac cycle and then relate the obtained strains to tensions, through local equilibrium equations, to estimate the local extensional stiffness at every position. A very good correlation between the rupture risk criterion and the local extensional stiffness was found. Finally we show that patients can be separated in two groups: a group of stiff and brittle ATAA and a group of relatively compliant ATAA. We also apply the LESI methodology to other modalities, e.g. ultrasound and MRI, to investigate the possibility of substituting CT scans by other modalities avoiding radiations.Une méthodologie appelée identification de la rigidité membranaire locale (LESI) a été développée pour identifier de manière non invasive la rigidité membranaire locale in vivo chez les patients souffrant d’anévrisme de l’aorte thoracique ascendante (AATA). Pour l’aorte thoracique, un diamètre supérieur à 5.5 cm est considéré comme anévrismal et une intervention chirurgicale est recommandée. Le diamètre en tant qu’indicateur de risque actuel entraîne un taux élevé d’interventions chirurgicales mal programmées. Il est suggéré d’aider les médecins à prendre la bonne décision en prenant en compte des facteurs biomécaniques tels que les propriétés matérielles, comme nous l’avions précédemment indiqué en montrant qu’il existe une corrélation significative entre un critère de rupture de l’ AATA basé sur la déformation et la rigidité membranaire locale de l’aorte. La tomodensitométrie et les pressions brachiales ont été utilisées pour évaluer le risque de rupture des AATAs. Nous appliquons la méthode LESI à 11 patients pour reconstruire la déformation tout au long du cycle cardiaque, puis associer les déformations obtenues à des tensions, par le biais d’équations d’équilibre locales, afin d’estimer la rigidité membranaire locale à chaque position. Une très bonne corrélation entre le critère de risque de rupture et la rigidité membranaire locale a été trouvée. Enfin, nous montrons que les patients peuvent être séparés en deux groupes: un groupe d’AATAs rigides et fragiles et un groupe d’ AATAs relativement extensibles. Nous appliquons également la méthodologie LESI à l’échographie et l’IRM, pour étudier la possibilité de remplacer le scanner par d’autres modalités

Assessment of the ascending thoracic aortic aneurysm rupture risk based on the local arterial stiffness

Une méthodologie appelée identification de la rigidité membranaire locale (LESI) a été développée pour identifier de manière non invasive la rigidité membranaire locale in vivo chez les patients souffrant d’anévrisme de l’aorte thoracique ascendante (AATA). Pour l’aorte thoracique, un diamètre supérieur à 5.5 cm est considéré comme anévrismal et une intervention chirurgicale est recommandée. Le diamètre en tant qu’indicateur de risque actuel entraîne un taux élevé d’interventions chirurgicales mal programmées. Il est suggéré d’aider les médecins à prendre la bonne décision en prenant en compte des facteurs biomécaniques tels que les propriétés matérielles, comme nous l’avions précédemment indiqué en montrant qu’il existe une corrélation significative entre un critère de rupture de l’ AATA basé sur la déformation et la rigidité membranaire locale de l’aorte. La tomodensitométrie et les pressions brachiales ont été utilisées pour évaluer le risque de rupture des AATAs. Nous appliquons la méthode LESI à 11 patients pour reconstruire la déformation tout au long du cycle cardiaque, puis associer les déformations obtenues à des tensions, par le biais d’équations d’équilibre locales, afin d’estimer la rigidité membranaire locale à chaque position. Une très bonne corrélation entre le critère de risque de rupture et la rigidité membranaire locale a été trouvée. Enfin, nous montrons que les patients peuvent être séparés en deux groupes: un groupe d’AATAs rigides et fragiles et un groupe d’ AATAs relativement extensibles. Nous appliquons également la méthodologie LESI à l’échographie et l’IRM, pour étudier la possibilité de remplacer le scanner par d’autres modalités.A methodology named local extensional stiffness identification (LESI) was developed to identify in vivo local extensional stiffness non-invasively in patients suffering from ascending thoracic aortic aneurysm (ATAA). An aneurysm is a ballooning of an artery, which can burst and lead to life threatening hemorrhage. For the thoracic aorta, a diameter greater than 5.5 cm is generally considered aneurysmal, and surgical intervention is recommended. The diameter as current risk indicator causes very high rate of misprogrammed surgical interventions. It this thesis it is suggested to assist physicians in taking the correct decision by considering biomechanical factors such as in vivo material properties of the tissue as we previously showed that there is a significant correlation between a stretch based rupture criterion of the ATAA and the local ex-tensional stiffness of the aorta. Gated computed tomography (CT) scans and brachial pressures were used to assess the risk of rupture of ATAAs. Using these images, we apply the LESI method for 11 patients to first reconstruct the strain throughout the cardiac cycle and then relate the obtained strains to tensions, through local equilibrium equations, to estimate the local extensional stiffness at every position. A very good correlation between the rupture risk criterion and the local extensional stiffness was found. Finally we show that patients can be separated in two groups: a group of stiff and brittle ATAA and a group of relatively compliant ATAA. We also apply the LESI methodology to other modalities, e.g. ultrasound and MRI, to investigate the possibility of substituting CT scans by other modalities avoiding radiations

Inverse identification of local stiffness across ascending thoracic aortic aneurysms

International audienceAortic dissection is the most common catastrophe of the thoracic aorta, with a very high rate of mortality. Type A dissection is often associated with an ascending thoracic aortic aneurysm (ATAA). However, it is widely acknowledged that the risk of type A dissection cannot be reliably predicted simply by measuring the ATAA diameter and there is a pressing need for more reliable risk predictors. It was previously shown that there is a signicant correlation between a rupture criterion based on the ultimate stretch of the ATAA and the local membrane sti-ness of the aorta. Therefore, reconstructing regional variations of the membrane stiness across the aorta appears highly important. In this paper, we present a novel noninvasive inverse method to identify the patientspecic local membrane stiness of aortic walls based on preoperative gated CT scans. Using these scans, a structural mesh is dened across the aorta with a set of nodes attached to the same material points at dierent time steps throughout the cardiac cycle. For each node, time variations of the position are analyzed using Fourier series, permitting the reconstruction of the local strain distribution (fundamental term). Relating these strains to tensions with the membrane stiness, and writing the local equi-2 Solmaz Farzaneh et al. librium satised by the tensions, the local membrane stiness is nally derived at every position. The methodology is applied onto the ascending and descending aorta of three patients. Interestingly, the regional distribution of identied stiness properties appears heterogeneous across the ATAA. Averagely, the identied sti-ness is also compared with values obtained using other non-local methodologies. The results support the possible non-invasive prediction of stretch-based rupture criteria in clinical practice using local stiness reconstruction

Patient-specific predictions of aneurysm growth and remodeling in the ascending thoracic aorta using the homogenized constrained mixture model

International audienceIn its permanent quest of mechanobiological homeostasis, our vascula-ture significantly adapts across multiple length and time scales in various physiological and pathological conditions. Computational modeling of vascular growth and remodeling (G&R) has significantly improved our insights of the mechanobio-logical processes of diseases such as hypertension or aneurysms. However, patient-specific computational modeling of ascending thoracic aortic aneurysm (ATAA) evolution, based on finite-element models (FEM), remains a challenging scientific problem with rare contributions, despite the major significance of this topic of research. Challenges are related to complex boundary conditions and geometries combined with layer-specific G&R responses. To address these challenges, in the current paper, we employed the constrained mixture model (CMM) to model the arterial wall as a mixture of different constituents such as elastin, collagen fiber families and smooth muscle cells (SMCs). Implemented in Abaqus as a UMAT, this first patient-specific CMM-based FEM of G&R in human ATAA was first validated for canonical problems such as single-layer thick-wall cylindrical and bi-layer thick-wall toric arterial geometries. Then it was used to predict ATAA evolution for a patient-specific aortic geometry, showing that the typical shape of an ATAA can be simply produced by elastin proteolysis localized in regions of deranged hemodymanics. The results indicate a transfer of stress to the adventitia by elastin loss and continuous adaptation of the stress distribution due to change of ATAA shape. Moreover, stress redistribution leads to collagen deposition where the maximum elastin mass is lost, which in turn leads to stiffening of the arterial wall. As future work, the predictions of this G&R framework will be validated on datasets of patient-specific ATAA geometries followed up over a significant number of years

Bioactive Properties of Eremostachys macrophylla Montbr. & Auch. Rhizomes Growing in Iran

Background: The current study was assigned to evaluate the antioxidant, general toxicity, anti-proliferative and antimicrobial activities of different extracts obtained from rhizomes of Eremostachys macrophylla (Lamiaceae). Methods: All activities were evaluated by obtaining extracts of E. macrophylla in n-hexane, DCM (dichloromethane) and MeOH (methanol) by soxhlet apparatus. The antioxidant activity of the extracts was evaluated in terms of FRST (free radical scavenging activity test) by DPPH (2, 2-diphenyl-1-picrylhydrazyl). BSLT (Brine shrimp lethality tests), MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide) assay and disc diffusion method were carried out to determine the general toxicity, anti-proliferative and antibacterial activities of the different extracts, respectively. Results: The findings of the study for antioxidant, anti-proliferative and antibacterial effects showed that DCM extract was the most active fraction, but n-hexane extract indicated the most potent effect against Artemia salina. Conclusion: The results revealed strong bioactive effects of nonpolar fractions of E. macrophylla rhizomes. Thus, it is possible to suggest some new potential antioxidant, cytotoxic and antibacterial agents with no harmful effects on noncancerous cells