207 research outputs found
Chemical synthesis of bacteriophage G4.
No full textBACKGROUND: Due to recent leaps forward in DNA synthesis and sequencing technology, DNA manipulation has been extended to the level of whole-genome synthesis. Bacteriophages occupy a special niche in the micro-organic ecosystem and have potential as a tool for therapeutic agent. The purpose of this study was to carry out chemical synthesis of the bacteriophage G4 and the study of its infectivity. METHODOLOGY/PRINCIPAL FINDINGS: Full-sized genomes of bacteriophage G4 molecules were completed from short overlapping synthetic oligonucleotides by direct assembly polymerase chain reaction and ligase chain reaction followed by fusion polymerase chain reaction with flanking primers. Three novel restriction endonuclease sites were introduced to distinguish the synthetic G4 from the wild type. G4 particles were recovered after electroporation into Escherichia coli and were efficient enough to infect another strain. The phage was validated by electron microscope. Specific polymerase chain reaction assay and restriction analyses of the plaques verified the accuracy of the chemical synthetic genomes. CONCLUSIONS: Our results showed that the bacteriophage G4 obtained is synthetic rather than a wild type. Our study demonstrated that a phage can be synthesized and manipulated genetically according to the sequences, and can be efficient enough to infect the Escherichia coli, showing the potential use of synthetic biology in medical application
Confidence Intervals Based on the Difference of Medians for Independent Log-Normal Distributions
No full textIn this paper, we study the inferences of the difference of medians for two independent log-normal distributions. These methods include traditional methods such as the parametric bootstrap approach, the normal approximation approach, the method of variance estimates recovery approach, and the generalized confidence interval approach. The simultaneous confidence intervals for the difference in the median for more than two independent log-normal distributions are also discussed. Our simulation studies evaluate the performances of the proposed confidence intervals in terms of coverage probabilities and average lengths. We find that the parametric bootstrap approach would be a suitable choice for smaller sample sizes for the two independent distributions and multiple independent distributions. However, the method of variance estimates recovery and normal approximation approaches are alternative competitors for constructing simultaneous confidence intervals, especially when the populations have large variance. We also include two practical applications demonstrating the use of the techniques on observed data, where one data set works for the PM2.5 mass concentrations in Bangkapi and Dindaeng in Thailand and the other data came from the study of nitrogen-bound bovine serum albumin produced by three groups of diabetic mice. Both applications show that the confidence intervals from the parametric bootstrap approach have the smallest length
Generalized Mixtures of Exponential Distribution and Associated Inference
No full textA new generalization of the exponential distribution, namely the generalized mixture of exponential distribution, is introduced. Some of its basic properties, such as hazard function, moments, order statistics, mean deviation, measures of uncertainly, and reliability probability, are studied. Three different estimation methods are investigated by the maximum likelihood estimator, least-square estimator, and weighted least-square estimator. The performances of the estimators are assessed by simulation studies. Real-world applications of the proposed distribution are explored, and data fitting results show that the new distribution performs better than its competitors
A novel variant of androgen receptor is associated with idiopathic azoospermia
No full textA variety of genetic variants can lead to abnormal human spermatogenesis. The androgen receptor (AR) is an important steroid hormone receptor that is critical for male sexual differentiation and the maintenance of normal spermatogenesis. In the present study, each exon of AR in 776 patients diagnosed with idiopathic azoospermia (IA) and 709 proven fertile men were sequenced using use panel re-sequencing methods to examine whether AR is involved in the pathogenesis of IA. Two synonymous variants and seven missense variants were detected. Of the missense variants, a luciferase assay demonstrated that the R630W variant reduced the transcriptional regulatory function of AR. This novel variant (p. R630W) of AR is the first to be identified in association with IA, thereby highlighting the importance of AR during spermatogenesis.National Natural Science Foundation of China [31271244, 81200465]; Guangdong Natural Science Foundation of China [2014A030313785]; Shenzhen Foundation of Science and Technology [GJHZ20140414170821192, JCYJ20140414170821337]; 'Three Outstanding Projects' of Shenzhen; Project of Shenzhen Engineering Center; Key Laboratory Project of Shenzhen Second People's HospitalSCI(E)[email protected]; [email protected]
Probiotics SOD inhibited food allergy via downregulation of STAT6-TIM4 signaling on DCs
No full textBacterial probiotics are of increasing use against intestinal disorders such as food allergy. However, the detailed molecular mechanism underlying probiotics-mediated anti-allergic effect remains unknown. In the present study, we orally treated OVA-sensitized mice with Bifidobacterium infantis (BB) for two weeks. It was found that OVA specific-IgE and-IgG levels in serum were significantly decreased after BB administration. BB treatment also significantly reduced the release of IL-4, -5, -13 in splenocytes. Besides, after challenge with OVA, the occurrence of temperature drop and diarrhea was dramatically reduced in BB group. Moreover, the protective effect of BB on allergic mice was correlated with its antioxidative enzyme, superoxide dismutase (SOD). The antioxidative effect of BB on Dendritic cells (DCs0 was further demonstrated to be mediated by cAMP/PKA signaling. We also found that the mRNA and protein expression levels of TIM4 were attenuated in BB group. Finally, ChIP-qPCR assay studies indicate that BB reduced the binding of STAT6 to its response elements in the TIM4 promoter. In conclusion, orally administration of BB protected allergic mice via attenuation of oxidative stress, which further reduced TIM4 expression by inhibiting its transcription factor STAT6.</p
Fault diagnosis and prevention of flow sensor for fuel supply system
No full textThe fuel supply system plays an important role in combustion engines, and thus a higher reliability is required. A novel fault diagnosis and prevention strategy are presented in this paper. The diagnosis model is built up based on deviation calculation by introducing the flow sensor principle, which take reference flow rate and measured flow rate as criteria. The estimation function between the fuel flow rate, outlet pressure and pump rotating speed is obtained, which could be used to estimate the fuel flow rate. The estimation method can provide the flow rate to the entire system and then keep the fuel supply system working reliably even when the sensors are in failure. Experimental results show the effectiveness of the proposed strategy in terms of accurate fault detection and robust prevention in the fuel supply system
A modified multi-angle suture training module for laparoscopic training curriculum on emergency intestinal surgery
No full textAbstract Background Intestinal perforation and intestinal obstruction are common emergency surgeries in clinics which often require intestinal resection and anastomosis. Most intestinal anastomosis can be completed by laparoscopy. The wound closure module In the Fundamentals of Laparoscopic Surgery (FLS) program is traditionally used for laparoscopic suture and knotting training. However, many young surgeons tend to focus on practicing suture techniques from certain or a limited range of angles. This narrow approach increases the difficulty of complex suturing and knotting in clinical scenarios such as laparoscopic intestinal anastomosis. Methods To address this issue, we designed a multi-angle suture module specifically for suture and knotting training. Thirty-six second-year surgical residents were recruited for the study. Twelve residents were randomly divided at a 1:1 ratio into the traditional suture group and the multi-angle suture group according to their basic laparoscopic surgical ability. After training, they were required to perform laparoscopic end-to-end anastomosis surgery on isolated swine intestines. Results The operation times, goal scores and surgical performance scores of the surgeries were collected and compared. Trainees who used the multi-angle suture training module shortened the operation time (3375.7 ± 1000 s vs. 4678.2 ± 684.7, p = 0.008) and achieved better surgical effects (operation performance score: 8.2 ± 1.5 vs. 6.83 ± 1.3, p = 0.041) in end‒end intestine anastomosis surgery than did those who used the traditional suture training module. Conclusions The multi-angle suture training module effectively improved the laparoscopic suture skills of trainees and is therefore a better choice for laparoscopic suture and knotting training before doing laparoscopic intestinal anastomosis
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