3,461 research outputs found
Application of extreme environmental conditions to resuscitation of viable but non culturable E. coli DH5α
The resuscitation of Viable But Non-Culturable (VBNC) state in Escherichia coli DH5α as one of the most usable
expression host was investigated. The VBNC state in bacteria is defined as while the cells are alive but unable to
grow visibly on nonselective growth medium. After collecting several samples, Non-culturable E. coli DH5α (that
has undertaken on various recombinant manipulations) were divided into different groups in order to carry-out
different experiments. They were treated to heat shock at 42ºC in different periods of time, different concentration of
Bile-salts and NaCl and combinational of these methods. The results showed that the almost of resuscitation
treatment had positive effect on reactivation of VBNC E. coli DH5α. The combination of these parameters (various
NaCl and bile salts concentration and heat shock method at 42 °C in different time) in a binary manner, also
inferred to suitable results. Furthermore, by applying the three stresses simultaneously we achieved optical density
up to 0.58 and 9×108 CFU/ml which had presented the best results. The results show that by applying some
alterations in the condition of such recombinant E. coli DH5α, the growth path of these bacteria which remain to a
VBNC phase can be changed to the normal status
Explicit finite element analysis of slope stability by strength reduction
The construction of stable slopes and vertical cuts is an important step in many geotechnical projects. Limit equilibrium methods (LEMs) are well-accepted procedures to compute factors of safety (FoS); however, they fail to provide any information about the distribution of the field variables within the soil mass because they do not include any stress-strain relationship in their formulation. On the other hand, the iterative finite element method (FEM/I) can estimate the field variables, but in the current study, we show that, for steep slopes and vertical cuts, it underestimates the FoS compared to the LEM. To overcome the obstacles that exist in this method, this study proposes a new approach to define the initiation of instability based on an abrupt change in the kinetic energy of the system. We also suggest a procedure to calculate the minimum FoS based on the explicit finite element method (FEM/E). Comparison of the results obtained from the proposed method, LEM, and FEM/I revealed that the FoS computed by the proposed method is in good agreement with the results of the LEM for a wide range of material parameters, geometries and external loading conditions, while no assumption regarding the critical slip surface needs to be made
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Testicular expression of TDRD1, TDRD5, TDRD9 and TDRD12 in azoospermia.
BACKGROUND: Tudor domain-containing proteins (TDRDs) play a critical role in piRNA biogenesis and germ cell development. piRNAs, small regulatory RNAs, act by silencing of transposons during germline development and it has recently been shown in animal model studies that defects in TDRD genes can lead to sterility in males. METHODS: Here we evaluate gene and protein expression levels of four key TDRDs (TDRD1, TDRD5, TDRD9 and TDRD12) in testicular biopsy samples obtained from men with obstructive azoospermia (OA, n = 29), as controls, and various types of non-obstructive azoospermia containing hypospermatogenesis (HP, 28), maturation arrest (MA, n = 30), and Sertoli cell-only syndrome (SCOS, n = 32) as cases. One-way ANOVA test followed by Dunnett's multiple comparison post-test was used to determine inter-group differences in TDRD gene expression among cases and controls. RESULTS: The results showed very low expression of TDRD genes in SCOS specimens. Also, the expression of TDRD1 and TDRD9 genes were lower in MA samples compared to OA samples. The expression of TDRD5 significantly reduced in SCOS, MA and HP specimens than the OA specimens. Indeed, TDRD12 exhibited a very low expression in HP specimens in comparison to OA specimens. All these results were confirmed by Western blot technique. CONCLUSION: TDRDs could be very important in male infertility, which should be express in certain stages of spermatogenesis
Associations between socio-environmental determinants and the risk of pulmonary tuberculosis in Guilan, Iran
Background: Certain social determinants may influence host susceptibility to tuberculosis (TB) infections, and increase the risk of developing the disease. Objectives: The present study aimed to evaluate the effects of several host and environmental factors on the risk of TB in northern Iranian households. Patients and Methods: This case control study was conducted for one year between 2010 and 2011 in the Guilan province in Iran. Eightyseven confirmed TB positive cases, based on convenience sampling, were included in this study. A patient positive for TB was confirmed by a positive sputum smear, chest X-ray, and clinical manifestations as diagnosed by a physician. The data were collected using observational methods, and were analyzed by SPSS software. Results: The average mean age of the TB cases was 51±22 years old, and 40.2 (35/87) of the TB cases were male and 59.8 (52/87) were female. The majority of TB cases were from rural areas (71.3, 62/87), while 28.7 (25/87) were from urban areas. Significant differences (P < 0.001) were observed between the geographical conditions and distribution of the disease. The room density of the individuals was significantly different (2.9±1.2 vs. 2.2±1.9, P<0.002) among the TB cases and control group, respectively. A statistical difference was observed between the groups in terms of the building materials (P < 0.05), while significantly inadequate UV irradiation was seen in the houses of the TB patients, compared to the control group (82.8 vs. 14.9,P<0.001). The hygiene of the houses seemed to be a significant risk factor (P<0.001) for TB infection.Conclusions: The results suggest that in the studied region several host and environmental factors were associated with higher risks of TB infection. © 2016, Infectious Diseases and Tropical Medicine Research Center
Peak Forecasting for Battery-based Energy Optimizations in Campus Microgrids
Battery-based energy storage has emerged as an enabling technology for a
variety of grid energy optimizations, such as peak shaving and cost arbitrage.
A key component of battery-driven peak shaving optimizations is peak
forecasting, which predicts the hours of the day that see the greatest demand.
While there has been significant prior work on load forecasting, we argue that
the problem of predicting periods where the demand peaks for individual
consumers or micro-grids is more challenging than forecasting load at a grid
scale. We propose a new model for peak forecasting, based on deep learning,
that predicts the k hours of each day with the highest and lowest demand. We
evaluate our approach using a two year trace from a real micro-grid of 156
buildings and show that it outperforms the state of the art load forecasting
techniques adapted for peak predictions by 11-32%. When used for battery-based
peak shaving, our model yields annual savings of $496,320 for a 4 MWhr battery
for this micro-grid.Comment: 5 pages. 4 figures, This paper will appear in the Proceedings of ACM
International Conference on Future Energy Systems (e-Energy'20), June 202
Stabilized Quasi-Newton Optimization of Noisy Potential Energy Surfaces
Optimizations of atomic positions belong to the most commonly performed tasks
in electronic structure calculations. Many simulations like global minimum
searches or characterizations of chemical reactions require performing hundreds
or thousands of minimizations or saddle computations. To automatize these
tasks, optimization algorithms must not only be efficient, but also very
reliable. Unfortunately computational noise in forces and energies is inherent
to electronic structure codes. This computational noise poses a sever problem
to the stability of efficient optimization methods like the limited-memory
Broyden-Fletcher-Goldfarb-Shanno algorithm. We here present a technique that
allows obtaining significant curvature information of noisy potential energy
surfaces. We use this technique to construct both, a stabilized quasi-Newton
minimization method and a stabilized quasi-Newton saddle finding approach. We
demonstrate with the help of benchmarks that both the minimizer and the saddle
finding approach are superior to comparable existing methods
Circular RNAs in cancer: New insights into functions and implications in ovarian cancer
Circular RNAs (circRNAs) are a class of long non-coding RNAs (lncRNAs) which have a circular and closed loop structure. They are ubiquitous, stable, conserved and diverse RNA molecules with a range of activities such as translation and splicing regulation, which are able to interacting with RNA-binding proteins and specially miRNA sponge. The expression patterns of the circRNAs exhibited tissue specificity and also, step and stage specificity. Accumulating evidences approved the critical role of circular RNAs in many cancers such as ovarian cancer. Given that these molecules exert their effects through multiple cellular and molecular mechanisms (i.e., angiogenesis, apoptosis, growth, and metastasis) which are involved in cancer pathogenesis, circular RNAs, in particular, act by controlling cell proliferation in ovarian cancer, so that, it has been shown that the deregulation of these molecules is associated with initiation and progression of ovarian cancer. Therefore, they are attractive molecules which have introduced them as cancer biomarkers. Moreover, they could be used as new therapeutic candidates for developing novel treatment strategies. Here, for first time, we have provided a comprehensive review on the recent knowledge of circular RNAs and their pathological roles in the ovarian cancer. © 2019 The Author(s)
Electrochemical-based biosensors for microRNA detection: Nanotechnology comes into view
Nanotechnology plays an undeniable significant role in medical sciences, particularly in the field of biomedicine. Development of several diagnostic procedures in medicine has been possible through the beneficial application of nano-materials, among which electrochemical nano-biosensors can be mentioned. They can be employed to quantify various clinical biomarkers in detection, evaluation, and follow up stages of the illnesses. MicroRNAs, a group of regulatory short RNA fragments, added a new dimension to the management and diagnosis of several diseases. Mature miRNAs are single-stranded RNA molecules approximately 22 nucleotides in length, which regulate a vast range of biological functions from cellular proliferation and death to cancer development and progression. Recently, diagnostic value of miRNAs in various diseases has been demonstrated. There are many traditional methods for detection of miRNAs including northern blotting, quantitative real time PCR (qRT-PCR), microarray technology, nanotechnology-based approaches, and molecular biology tools including miRNA biosensors. In comparison with other techniques, electrochemical nucleic acid biosensor methods exhibit many interesting features, and could play an important role in the future nucleic acid analysis. This review paper provides an overview of some different types of nanotechnology-based biosensors for detection of miRNAs. © 201
Antibiotic resistance pattern and distribution of psla gene among biofilm producing pseudomonas aeruginosa isolated from waste water of a burn center
Background: Pseudomonas aeruginosa is considered as a major cause of hospital-acquired infections due to its high antibacterial resistance. Biofilm formation is a well-known pathogenic mechanism in P. aeruginosa infections, since sessile bacteria are protected in an extracellular matrix of exopolysaccharide. The expression of polysaccharide synthesis locus (pslA gene) can be important for biofilm formation by P. aeruginosa. Objectives: The purpose of this research was to evaluate the antibiotic resistance pattern and distribution of the pslA gene among biofilm-producing P. aeruginosa isolates obtained from waste water of Burn Centre in Guilan, Iran. Materials and Methods: Fifty isolates of P. aeruginosa were obtained from waste water of a burn center. The P. aeruginosa isolates were identified using standard bacteriological procedures. Drug susceptibility test was performed by disk diffusion method for all the isolates against nine antimicrobial agents. Biofilm formation was measured by microtiter plate assay. Polymerase chain reaction (PCR) was used to identify the presence of the pslA gene among the isolates. Results: Biofilm formation was observed in 70 of the P. aeruginosa isolates. The potential formation of biofilm was significantly associated with resistance to gentamicin, imipenem, tobramycin and piperacillin. In addition, the pslA gene only existed in biofilm-producing isolates with a frequency of 42.9 (n = 15).Conclusions: The findings of the present study well demonstrated that the P. aeruginosa biofilm-producing isolates were more resistant to the tested antibiotics. Furthermore, because of wide distribution, it seems that the pslA gene is associated with biofilm formation. � 2015, Ahvaz Jundishapur University of Medical Sciences
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