Relative homological rings and modules

The study of rings and modules with homological criteria is a cornerstone of commutative algebra. Let $R$ be a commutative Noetherian ring with identity (not necessarily local) and $\frak a$ a proper ideal of $R$. In this paper, a relative analogue of the theory of homological rings and modules is developed. We introduce the notions of $\frak a$-relative regular, $\frak a$-relative complete intersection, and $\frak a$-relative Gorenstein rings and modules. We extend some classical results by demonstrating some interactions between these types of rings and modules.Comment: to appear in the Rocky Mountain Journal of Mathematic

Dualities and equivalences of the category of relative Cohen-Macaulay modules

In this paper, we establish the global analogues of some dualities and equivalences in local algebra by developing the theory of relative Cohen-Macaulay modules. Let R be a commutative Noetherian ring (not necessarily local) with identity and a a proper ideal of R. The notions of a-relative dualizing modules and a-relative big Cohen-Macaulay modules are introduced. With the help of a-relative dualizing modules, we establish the global analogue of the duality on the subcategory of Cohen-Macaulay modules in local algebra. Lastly, we investigate the behavior of the subcategory of a-relative Cohen-Macaulay modules and a-relative generalized Cohen-Macaulay modules under Foxby equivalence.Comment: to appear in the Journal of Commutative Algebr

Study of gyrA S83R Mutation Rate in Vancomycin Resistant Entrococcus Faecium

Enterococci are among Gram-positive cocci and are common inhabitants of the human gastrointestinal tract and enough potent to cause serious infections such as bacteremia, urinary tract infections (UTIs) and endocarditis. Enterococci are not generally considered as highly infectious bacterium. However, the main reason for treatment failure in enterococcal infections is acquired resistance to glycopeptide antibiotics, specifically vancomycin. Most enterococcal infections in human such as gastroenteritis, intestinal infections, and endocarditis have been caused by E. faecalis and E. facieum. They are holding the second place of most frequent cause of hospital infections since 1990. In present study gyrA S83R polymorphism rate in vancomycin resistant Enterococcus faecium isolated from environment, food industries, and hospitals of Tehran were examined by ARMS-PCR technique. DNA was extracted from the bacterial colonies using standard column method, after separating the samples into two groups of antibiotic resistant and antibiotic susceptible by antibiogram test. A fragment of gyrA gene was amplified using PCR method to investigate point mutation of S83R position. ARMS-PCR technique was applied to detect the presence or absence of mutation using a set of specified primers which can be annealed when the mutation is present. The results were statistically analyzed by chi-square test (p < 0.05) using SPSS 19th version. The results showed that there was a significant correlation between the presences of S83R polymorphism with vancomycin resistance trait in Entrococcus faecium. Therefore, this technique could be used as a diagnostic tool to detect vancomycin resistance cases of E. faecium in patients and environment.HIGHLIGHTS•There is a strong association between the presence of point mutation at the position of Ser83 and vancomycin resistant phenotype.•Resistance in Enterococcus spp. is highly mediated by mutations in gyrA gene which plays a major role in interaction with vancomycin.•Vancomycin is the only drug that can be consistently relied on for the treatment of infections caused by multidrug resistant enterococci.•VRE has presented a serious challenge for the Iranian medical community

Cytotoxicity of Selected Nanoparticles on Human Dental Pulp Stem Cells

Introduction: Nanoparticles are being increasingly applied in dentistry due to their antimicrobial and mechanical properties. This in vitro study aimed to assess and compare the cytotoxicity of four metal oxide nanoparticles (TiO2, SiO2, ZnO, and Al2O3) on human dental pulp stem cells. Methods and Materials: Four suspension with different concentrations (25, 50, 75, 100 µg/mL) of each nanoparticle were prepared and placed into cavities of three 96-well plates (containing 1×104 cells per well that were seeded 24 earlier). All specimens were incubated in a humidified incubator with 5% CO2 at 37°C. Mosmann’s Tetrazolium Toxicity (MTT) assay was used to determine in vitro cytotoxicity of test materials on pulpal stem cells. Cell viability was determined at 24, 48, and 72 h after exposure. Data comparisons were performed using a general linear model for repeated measures and Tukey's post hoc test. The level of significance was set at 0.05. Results: The tested nanoparticles showed variable levels of cytotoxicity and were dose and time dependant. The minimum cell viability was observed in ZnO followed by TiO2, SiO2 and Al2O3. Conclusion: The results demonstrated that cell viability and morphological modifications occurred at the concentration range of 25 to 100 µg/mL and in all nanoparticles. The higher concentration and longer duration of exposure increased cellular death. Our results highlight the need for a more discrete use of nanoparticles for biomedical applications.Keywords: Cytotoxicity; Dental Pulp Stem Cells; Metal Oxide Nanoparticle

Selective Noise Based Power-Efficient and Effective Countermeasure against Thermal Covert Channel Attacks in Multi-Core Systems

With increasing interest in multi-core systems, such as any communication systems, infra-structures can become targets for information leakages via covert channel communication. Covert channel attacks lead to leaking secret information and data. To design countermeasures against these threats, we need to have good knowledge about classes of covert channel attacks along with their properties. Temperature–based covert communication channel, known as Thermal Covert Channel (TCC), can pose a threat to the security of critical information and data. In this paper, we present a novel scheme against such TCC attacks. The scheme adds selective noise to the thermal signal so that any possible TCC attack can be wiped out. The noise addition only happens at instances when there are chances of correct information exchange to increase the bit error rate (BER) and keep the power consumption low. Our experiments have illustrated that the BER of a TCC attack can increase to 94% while having similar power consumption as that of state-of-the-art

Investigating the Morphologic Indices of the Hamulus Pterygoid Process Using the CBCT Technique

Location and length of hamulus process plays a very important role in the efficiency of muscles such as tensor veli palatine, palato pharyngeal, upper part of upper throat muscle and so on. Given the importance of information on the morphology of the hamular process and capabilities and usefulness of CBCT in the diagnosis of its structure, this study takes place with the goal of investigating the morphologic indices (indicators) of hamulus pterygoid process using CBCT. This study investigates the CBCT images of 201 patients with the average age of 37 years, 102 males and 99 females. The length and width of the hamulus process on the left and right was measured. Also, the slope of this process in the sagittal and coronal planes were studied. Then variables in question were measured by a CBCT viewer. Average length of hamulus pterygoid process on the right was found to be 6.4 mm and on the left it was 6.5 mm. Average width of hamulus pterygoid process on the right was found to be 1.34 mm and on the left it was 1.35 mm. The average slope of the hamulus pterygoid process in the sagittal plane on the right was found to be 55.9 ° and on the left it was 56.7° The average slope of the hamulus pterygoid process in the coronal plane on the right was found to be 65.7 ° and on the left it was 66.5°. Average length and width of the hamulus process on the two sides did not make a statistically significant difference. But the average slope in the sagittal and coronal plane on the left was significantly higher than the one on the right. Average length of hamulus pterygoid process on the two sides was significantly higher in men than women. Average width of hamulus pterygoid process and the slope in the sagittal and coronal planes did not make any difference on both sides in both genders. Average length, width and slope of hamulus pterygoid process in the sagittal plan reduces on both sides with increase in age. But the slope of the hamulus pterygoid process in the coronal plane did not make any significant difference in different age groups on both sides. The slope of pterygoid process was towards the lateral in and in the sagittal plane the slope was towards the posterior. The morphological evaluation of the hamulus pterygoid process in the CBCT images can contribute to the tracking and management of vague non diagnostic symptoms in the palate

Restoration of Harmane Induced Memory Consolidation Deficit by Alpha-lipoic Acid in Male Mice

Introduction: there has been a growing number of publications focusing on the effect of beta-carbolines (e.g., harmane) on cognitive behaviors such as different stages of memory formation process. Moreover, several studies have stated that Alpha-lipoic acid (ALA) induces some molecular pathways effects including antioxidant effect and reduction of inflammation process. Thus, in the lines that follow, the question of whether ALA could alter memory consolidation deficit caused by harmane in the male NMRI mice will be addressed. Materials and Methods: The data for this study were collected by step-down inhibitory avoidance task with one trial protocol for evaluation of memory consolidation. The ALA (35 mg/kg) was injected intraperitoneally immediately after training followed by subthreshold and effective doses of harmane (2.5, 5 and 10 mg/kg) with 15-minute interval period. Results: The results show that post-training injection of the highest dose of harmane (10 mg/kg) lowers step-down latency, indicating the amnesia induced by harmane (P<.001). In addition, similar injection of subthreshold dose of ALA (35 mg/kg), 15 minutes before injection of subthreshold and effective doses of harmane, restores step-down latency caused by higher dose of harmane (P<.001) without its effect on the responses induced by subthreshold doses of harmane, indicating benefit effect of ALA on amnesia induced by harmane. Conclusion: An implication of this study is the possibility that ALA can reverse the amnesia induced by harmane. Therefore, future studies on this topic such as molecular mechanisms are recommended. &nbsp

Early versus Late Decompression for Traumatic Spinal Cord Injuries; a Systematic Review and Meta-analysis

Introduction: Despite the vast number of surveys, no consensus has been reached on the optimum timing of spinal decompression surgery. This systematic review and meta-analysis aimed to compare the effects of early and late spinal decompression surgery on neurologic improvement and post-surgical complications in patients with traumatic spinal cord injuries.Methods: Two independent reviewers carried out an extended search in electronic databases. Data of neurological outcome and post-surgery complication were extracted. Finally, pooled relative risk (RR) with a 95% confidence interval (CI) was reported for comparing of efficacy of early and late surgical decompression.Results: Eventually 22 studies were included. The pooled RR was 0.77 (95% CI: 0.68-0.89) for at least one grade neurological improvement, and 0.84 (95% CI: 0.77-0.92) for at least two grade improvement. Pooled RR for surgical decompression performed within 12 hours after the injury was 0.26 (95% CI: 0.13-0.52; p<0.001), while it was 0.75 (95% CI: 0.63-0.90; p=0.002) when the procedure was performed within 24 hours, and 0.93 (95% CI: 0.76-1.14; p=0.48) when it was carried out in the first 72 hours after the injury. Surgical decompression performed within 24 hours after injury was found to be associated with significantly lower rates of post-surgical complications (RR=0.77; 95% CI: 0.68-0.86; p<0.001).Conclusion: The findings of this study indicate that early spinal decompression surgery can improve neurologic recovery and is associated with less post-surgical complications. The optimum efficacy is observed when the procedure is performed within 12 hours of the injury

Application of Ultrasonography and Radiography in Detection of Hemothorax: a Systematic Review and Meta-Analysis

Introduction: Hemothorax is one of the most prevalent injuries caused by thoracic traumas. Early detection and treatment of this injury is of utmost importance in prognosis of the patient, but there are still controversial debates on the diagnostic value of imaging techniques in detection of hemothorax. Therefore, the present study aimed to evaluate the diagnostic value of chest ultrasonography and radiography in detection of hemothorax through a systematic review and meta-analysis. Methods: Two independent reviewers performed an extended systematic search in databases of Medline, EMBASE, ISI Web of Knowledge, Scopus, Cochrane Library, and ProQuest. Data were extract and quality of the relevant studies were assessed. The number of true positive, false positive, true negative and false negative cases were extracted and screening performance characteristics of two imaging techniques were calculated using a mixed-effects binary regression model. Results: Data from 12 studies were extracted and included in the meta-analysis (7361 patients, 77.1% male). Pooled sensitivity and specificity of ultrasonography in detection of hemothorax were 0.67 (95% CI: 0.41-0.86; I2= 68.38, p<0.001) and 0.99 (95% CI: 0.95-1.0; I2= 88.16, p<0.001), respectively. These measures for radiography were 0.54 (95% CI: 0.33-0.75; I2= 92.85, p<0.001) and 0.99 (95% CI: 0.94-1.0; I2= 99.22, p<0.001), respectively. Subgroup analysis found operator of the ultrasonography device, frequency of the transducer and sample size to be important sources of heterogeneity of included studies. Conclusion: The results of this study showed that although the sensitivity of ultrasonography in detection of hemothorax is relatively higher than radiography, but it is still at a moderate level (0.67%). The specificity of both imaging modalities were found to be at an excellent level in this regard. The screening characteristics of ultrasonography was found to be influenced of the operator and frequency of transducer