Effect of Equal Channel Angular Pressing (ECAP) on Wear Behavior of Al-7075 Alloy

AbstractEqual-channel angular pressing (ECAP) is an effective fabrication process for obtaining ultrafine grained materials. In order to investigate the effect of grain refinement during ECAP on wear properties of Al 7075 alloy, the specimens were pressed up to four passes by route BC at room temperature. Followed by ECAP, dry sliding wear tests have been conducted using a pin-on-disk machine under different loads of 10, 20 and 30N at a constant sliding speed of 0.23 ms-1. Microstructural observations were undertaken using transmission electron microscopy (TEM) and the surface of worn specimens was investigated by scanning electron microscopy (SEM). The effect of load and ECAP process on the mass loss, have been explained with respect to microstructure and wear mechanism. Comparison of wear resistance of specimens shows that by using ECAP process, wear resistance of the specimens increases considerably due to the formation of very fine grains during ECAP

Study of temporal and spatial variations of physical parameters (temperature, salinity and density) trend of the Pozm Bay

Pozm bay Located in southern coast of Iran near Oman Sea, due to its relative calmness, low depth and being affected by the land substances is interesting to some aquatics species for reproduction and spending part of their growth period. In this research the seasonal variations of physical parameters trend of the Pozm pay was investigated during 9 periods since Oct 2011 till Aug 2012. The physical parameters of the sea water were measured by the CTD device in 17 stations from surface to seabed. These parameters are as follows: Temperature, Salinity, Density, Electrical conductivity, Sound velocity, Turbidity, and the Dissolved oxygen. According to the results of this research, the variations of the water temperature are following the air temperature and increase as the air temperature arises in hot seasons. Although due to the low depth of Pozm bay the formation of thermocline layer and water stratification are so low, weak stratification is formed in water column during hot months of the year. The entering flow of Oman Sea water into the Persian Gulf, which is less salty comparing to that of Persian Gulf, is maximized during late spring and minimized in winter and affects the salinity of Pozm bay water such that its rate is more during mild months than hot months. The variation of the density is influenced by water temperature and the salinity has no effect on them. The summer monsoon has a significant effect on the physical parameters of Pozm bay's water

Interactive Visual Labelling versus Active Learning: An Experimental Comparison

Methods from supervised machine learning allow the classification of new data automatically and are tremendously helpful for data analysis. The quality of supervised maching learning depends not only on the type of algorithm used, but also on the quality of the labelled dataset used to train the classifier. Labelling instances in a training dataset is often done manually relying on selections and annotations by expert analysts, and is often a tedious and time-consuming process. Active learning algorithms can automatically determine a subset of data instances for which labels would provide useful input to the learning process. Interactive visual labelling techniques are a promising alternative, providing effective visual overviews from which an analyst can simultaneously explore data records and select items to a label. By putting the analyst in the loop, higher accuracy can be achieved in the resulting classifier. While initial results of interactive visual labelling techniques are promising in the sense that user labelling can improve supervised learning, many aspects of these techniques are still largely unexplored. This paper presents a study conducted using the mVis tool to compare three interactive visualisations, similarity map, scatterplot matrix (SPLOM), and parallel coordinates, with each other and with active learning for the purpose of labelling a multivariate dataset. The results show that all three interactive visual labelling techniques surpass active learning algorithms in terms of classifier accuracy, and that users subjectively prefer the similarity map over SPLOM and parallel coordinates for labelling. Users also employ different labelling strategies depending on the visualisation used

Highly Efficient Formylation of Alcohols, Thiols and Aniline Derivatives by a Heterogeneous (HCOOH/SiO2) System under Microwave Irradiation and Solvent-free Conditions

A simple, rapid and efficient microwave-assisted procedure for the formylation of aniline derivatives and alcohols, using a heterogeneous (HCOOH/SiO2) system under solvent-free conditions is reported. The method is applied to a set of amines, alcohols and thiols and short reaction times (<10 min) with high yields are reported. This protocol introduces a practical and viable green technology of solvent-free and catalyst-free reactions.Keywords: Alcohols, anilines, SiO2, HCOOH, microwave irradiation, solvent-free condition

Complications of transcatheter closure in patent ductus arteriosus patients

Background: Published studies have shown excellent success rates and also low rates of life-threatening complications with trans-catheter closure of patent ductus arteriosus (PDA). However, most studies to date have been conducted in developed nations and reports from developing countries such as Iran are lacking. Objectives: To report our experience with trans-catheter closure of patent ductus arteriosus (PDA) and compare two devices and complications. Patients and Methods: From 2007 to 2011, 72 consecutive PDA cases were prospectively enrolled. For PDAs � 2 mm, the coiling method was employed whereas patients with PDA > 2 mm received Amplatzer duct occlusion (ADO). Success was defined as trivial residual shunt (< 1 mm) in the echocardiography performed 30 minutes after the procedure. After the procedure, the patients were admitted to the pediatric cardiology ward and observed for 72 hours during which the occurrence of major and minor complications was monitored. Major complications included cardiac arrest, displacement and/or embolization of the device and patient needing blood transfusion due to severe hemorrhage. Sampling was based on convenience method and the patients who had significant pulmonary artery hypertension were excluded from our study. Statistical analyses were done using SPSS software version 23 (IBM corp., New York, United States). Continuous variables are presented as mea

A systematic review of case reports of hepatic actinomycosis

Background: Hepatic Actinomycosis (HA) is one of the infections that causes disorders in patients when diagnosed untimely and inappropriately. Methods: Case reports on HA in patients published between 2000 and April 2020 were gathered by carrying out a structured search through PubMed/Medline. Results: Through a survey of the Medline database, 130 studies were identified and then, 64 cases with HA were included in the final analysis. Asia had the largest share of cases with 37.5 (24 reports), followed by Europe and the Americas. Affected patients were predominantly males (64) and the overall mortality rate was 1 with only one male patient in his 50 s dying. Nearly all patients (92) were immunocompetent. However, in four patients, the use of immunosuppressive medication led to depression of the immune system. Most of the patients (80) experienced complications. In terms of the complications, the most frequent ones were previous history of abdominal surgery (32) and foreign bodies in the abdominopelvic region (20). Actinomyces israelii was the most common pathogen isolated from patients. Abdominal pain (66), fever (62), weight loss (48), night sweat, malaise, and anorexia (14) over about 3.1 months were the most frequently reported clinical symptoms. Extension to one or more surrounding organs was evident in 18 patients (28). Histopathologic examination confirmed infection in 67 of the patients and samples obtained from liver puncture biopsy (32) were most frequently used in diagnosis. Surgery or puncture drainage + anti-infection was the most common method to treat patients and penicillin, Amoxicillin, Doxycycline, and ampicillin were the most frequently used drugs to control infection. Conclusion: HA should be considered in patients with a subacute or chronic inflammatory process of the liver. With accurate and timely diagnosis of infection, extensive surgery can be prevented. © 2021, The Author(s)

Bacteriophage therapy for inhibition of multi drug�resistant uropathogenic bacteria: a narrative review

Multi-Drug Resistant (MDR) uropathogenic bacteria have increased in number in recent years and the development of new treatment options for the corresponding infections has become a major challenge in the field of medicine. In this respect, recent studies have proposed bacteriophage (phage) therapy as a potential alternative against MDR Urinary Tract Infections (UTI) because the resistance mechanism of phages differs from that of antibiotics and few side effects have been reported for them. Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis are the most common uropathogenic bacteria against which phage therapy has been used. Phages, in addition to lysing bacterial pathogens, can prevent the formation of biofilms. Besides, by inducing or producing polysaccharide depolymerase, phages can easily penetrate into deeper layers of the biofilm and degrade it. Notably, phage therapy has shown good results in inhibiting multiple-species biofilm and this may be an efficient weapon against catheter-associated UTI. However, the narrow range of hosts limits the use of phage therapy. Therefore, the use of phage cocktail and combination therapy can form a highly attractive strategy. However, despite the positive use of these treatments, various studies have reported phage-resistant strains, indicating that phage�host interactions are more complicated and need further research. Furthermore, these investigations are limited and further clinical trials are required to make this treatment widely available for human use. This review highlights phage therapy in the context of treating UTIs and the specific considerations for this application. © 2021, The Author(s)

Investigation on wave energy in Amirabad seaport of Caspian Sea using SWAN model results

In this study, SWAN numerical model used to modeling waves and obtain the significant wave height in range of Amirabad seaport of Caspian Sea. To do this, first, a general model to modeling the wave height in the entire Caspian Sea was built. Then the boundary conditions obtained from the general model, by using the NEST operation of SWAN model, modeling the local with higher magnification in the area Amirabad Seaport was used. The local models built in the Amirabad, was calibration and verification with waves profile data recorded by buoys deployed in that area. Comparison the results with data measured by the Amirabad buoy shows that modeling done in this area had a good accuracy. Then running the SWAN model for three years and Obtained significant wave height in the desired location. Finally the wave energy obtained from significant wave height

Bacteriophage therapy against Pseudomonas aeruginosa biofilms: A review

Multi-Drug Resistant (MDR) Pseudomonas aeruginosa is one of the most important bacterial pathogens that causes infection with a high mortality rate due to resistance to different antibiotics. This bacterium prompts extensive tissue damage with varying factors of virulence, and its biofilm production causes chronic and antibiotic-resistant infections. Therefore, due to the non-applicability of antibiotics for the destruction of P. aeruginosa biofilm, alternative approaches have been considered by researchers, and phage therapy is one of these new therapeutic solutions. Bacteriophages can be used to eradicate P. aeruginosa biofilm by destroying the extracellular matrix, increasing the permeability of antibiotics into the inner layer of biofilm, and inhibiting its formation by stopping the quorum-sensing activity. Furthermore, the combined use of bacteriophages and other compounds with anti-biofilm properties such as nanoparticles, enzymes, and natural products can be of more interest because they invade the biofilm by various mechanisms and can be more effective than the one used alone. On the other hand, the use of bacteriophages for biofilm destruction has some limitations such as limited host range, high-density biofilm, sub-populate phage resistance in biofilm, and inhibition of phage infection via quorum sensing in biofilm. Therefore, in this review, we specifically discuss the use of phage therapy for inhibition of P. aeruginosa biofilm in clinical and in vitro studies to identify different aspects of this treatment for broader use. © 2020 The Author(s)

Aspergillosis of central nervous system in patients with leukemia and stem cell transplantation: a systematic review of case reports

Background: Aspergillosis of Central Nervous System (CNS) is a highly lethal infection in patients with leukemia and Stem Cell Transplantation (SCT). Methods: Case reports of CNS aspergillosis in patients with leukemia and SCT published between 1990 and August 2020 were gathered using a structured search through PubMed/Medline. Results: Sixty-seven cases were identified over the searches of the PubMed bibliographic database and then, 59 cases were included in the final analysis. Europe had the largest share of cases at 57.6 (34 reports), followed by Americas and Asia. Affected patients were predominantly males (58.6) and the mean age of the patients was 36.1 years, while 62.7 of the patients were under the age of 50 years. The most common leukemia types include Acute Lymphoblastic Leukemia (ALL), Chronic Lymphocytic Leukemia (CLL), and Acute Myeloid Leukemia (AML) at 43.4, 27.4, and 23.5, respectively. Furthermore, stem cell transplantation was reported in 11 cases. The overall mortality was 33; however, the attributable mortality rate of CNS aspergillosis was 24.5. Altered mental status, hemiparesis, cranial nerve palsies, and seizures were the clearest manifestations of infection and lung involvement reported in 57 of the patients. Histopathologic examination led to the diagnosis of infection in 57 of the patients followed by culture (23.7), galactomannan assay (8.5), and molecular method (3.3). Amphotericin B and voriconazole were the most frequently used drugs for infection treatment. Good results were not obtained in one-third of the patients treated by voriconazole. Finally, neurosurgical intervention was used for 23 patients (39). Conclusion: CNS aspergillosis is a rapidly progressive infection in leukemic patients. Thus, these patients should be followed up more carefully. Furthermore, management of induction chemotherapy, use of different diagnostic methods, and use of appropriate antifungal can lead to infection control. © 2021, The Author(s)