Equipment failure rate updating-Bayesian estimation

The paper presents a Bayes' method for augmenting generic equipment failure data with a prior distribution - predicated on the evidence, e.g., plant data - resulting in a posterior distribution. The depth of the evidence is significant in shaping the characteristics of the posterior distribution. In conditions of insufficient data about the prior distribution or great uncertainty in the generic data sources, we may use "constrained non-informative priors". This representation of the prior preserves the mean value of the failure rate estimate and maintains a broad uncertainty range to accommodate the site-specific event data. Although the methodology and the case study presented in this paper focus on the calculation of a time-based (i.e., failures per unit time) failure rate, based on a Poisson likelihood function and the conjugate gamma distribution, a similar method applies to the calculation of demand failure rates utilizing the binomial likelihood function and its conjugate beta distribution.     

Effects of high doses of theophylline on memory acquisition

Although tourniquets are used commonly during anterior cruciate ligament (ACL) surgery, little data are available regarding their effects on postoperative function. This retrospective study evaluated 94 patients who had an arthroscopically assisted, autogenous bone-patellar ligament-bone ACL reconstruction between 1988 and 1991 at the San Diego Kaiser Hospital. A tourniquet was used in 48 patients (T+ group). No tourniquet was used in 46 patients (T- group). The surgical and postoperative protocols were identical for the two groups. There were no bleeding complications. There was no significant difference in anesthesia time between the two groups. This study has shown that ACL surgery can be performed expeditiously without a pneumatic tourniquet. Quadriceps strength recovery after surgery was less in the T+ group at 12 weeks after surgery, but there was no significant difference between the groups 52 weeks after surgery. Difference in thigh girth was greater in T+ group 6 and 12 weeks after surgery, but there was no significant difference between the groups 52 weeks after surgery.     

Histopathological graded liver lesions: what role does the IVIM analysis method have?

Magnetic Resonance Materials in Physics, Biology and Medicine - This study aims to investigate three different image processing methods on quantitative parameters of IVIM sequence, as well as...     

Preparation,Optimization, and Characterization of Topotecan Loaded PEGylated Liposomes Using Factorial Design

This study reports the development of liposomal system for a potent antitumor drug, topotecan. To achieve this goal conventional and PEGylated liposomes were prepared according to a factorial design by hydration method followed by extrusion. Parameters such as type of lipid, percentage of cholesterol, percentage of phosphatidylglycerols, percentage of polyethylene glycol (PEG)-lipids, and drug to lipid molar ratio were considered as important factors for the optimizing the entrapment and retention of topotecan inside the liposomes. The size and zeta-potential of the PEGylated and conventional liposomes were measured by particle size analyzer and zeta-potentiometer, respectively. The stability and release characteristics of PEGylated liposome loaded topotecan were compared with conventional liposomes and free topotecan.

The optimized PEGylated [distearoyl phosphatidylcholine (DSPC)/cholesterol/ distearoyl phosphatidylglycerol (DSPG)/ distearoyl phosphatidylethanolamine-PEG₂₀₀₀ (DSPE-PEG₂₀₀₀); 7:7:3:1.28] and related conventional [DSPC/cholesterol/DSPG; 7:7:3] liposomes showed a narrow size distribution with a polydipersity index of 0.15 and 0.10, an average diameter of 103.0 ± 13.1 and 95.2 ± 11.10 nm, and with drug loading of 11.44 and 6.21%, respectively. Zeta-potential was ?10 ± 2.3 and ?22 ± 2.8 mV for PEGylated and conventional liposomes, respectively. The results of stability evaluation showed that the lactone ring of topotecan was notably preserved upon liposome encapsulation. PEGylated liposomes containing topotecan showed a significant decrease (P < 0.001) in release rate in comparison with conventional leptosomes. These results indicate the suitability of PEGylated liposomes in controlling topotecan release.

The prepared liposomes (especially PEGylated liposomes) as those described here may be clinically useful to stabilize and deliver topotecan for the treatment of cancer.     

Application of a hazard and operability study to hazard evaluationof an absorption heat pump

A hazard evaluation for a double-effect, absorption heat pump is presented. The primary technique for the hazard evaluation was a hazard and operability (HAZOP) study; this is a brainstorming approach conducted by a multidisciplinary team. The approach stimulates creativity of the team members to generate ideas. The team consisted of a HAZOP leader, the heat-pump project manager, a thermohydrologist, a corrosion specialist, a toxicologist, and a risk analyst. The majority of the team members were already involved in the design and analysis of the heat pump     

Preparation, optimization, and characterization of topotecan loaded PEGylated liposomes using factorial design

This study reports the development of liposomal system for a potent antitumor drug, topotecan. To achieve this goal conventional and PEGylated liposomes were prepared according to a factorial design by hydration method followed by extrusion. Parameters such as type of lipid, percentage of cholesterol, percentage of phosphatidylglycerols, percentage of polyethylene glycol (PEG)-lipids, and drug to lipid molar ratio were considered as important factors for the optimizing the entrapment and retention of topotecan inside the liposomes. The size and zeta-potential of the PEGylated and conventional liposomes were measured by particle size analyzer and zeta-potentiometer, respectively. The stability and release characteristics of PEGylated liposome loaded topotecan were compared with conventional liposomes and free topotecan. The optimized PEGylated [distearoyl phosphatidylcholine (DSPC)/cholesterol/ distearoyl phosphatidylglycerol (DSPG)/ distearoyl phosphatidylethanolamine-PEG(2000) (DSPE-PEG(2000)); 7:7:3:1.28] and related conventional [DSPC/cholesterol/DSPG; 7:7:3] liposomes showed a narrow size distribution with a polydipersity index of 0.15 and 0.10, an average diameter of 103.0 +/- 13.1 and 95.2 +/- 11.10 nm, and with drug loading of 11.44 and 6.21%, respectively. Zeta-potential was -10 +/- 2.3 and -22 +/- 2.8 mV for PEGylated and conventional liposomes, respectively. The results of stability evaluation showed that the lactone ring of topotecan was notably preserved upon liposome encapsulation. PEGylated liposomes containing topotecan showed a significant decrease (P < 0.001) in release rate in comparison with conventional leptosomes. These results indicate the suitability of PEGylated liposomes in controlling topotecan release. The prepared liposomes (especially PEGylated liposomes) as those described here may be clinically useful to stabilize and deliver topotecan for the treatment of cancer.     

Synthesis and characterization of a drug‐delivery system based on melamine‐modified poly(vinyl acetate‐co‐maleic anhydride) hydrogel

Three‐dimensional polymeric networks, which quickly swell by imbibing a large amount of water or deswell in response to changes in their external environment, are called hydrogels. These types of polymeric materials are good potential candidates for drug‐delivery systems. In this study, we first synthesized poly(vinyl acetate‐co‐maleic anhydride) by free‐radical copolymerization. Then, they were modified with different molar ratios of melamine to prepare hydrogels that could be used in drug‐delivery systems. The hydrogels were characterized by Fourier transform infrared spectroscopy, ¹H‐NMR, differential scanning calorimetry, and scanning electron microscopy. In the second step, Ceftazidime antibiotic was loaded on selected hydrogels. The in vitro drug release was investigated and compared in three different media (HCl solution at pH = 3 and buffer solutions at pH 6.1and pH 8). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40389.     

Assessment of possible protective roles of selenium, zinc, and cis-stilbene oxide against acute T-2 toxin poisoning: a preliminary report

The efficacy of two free radical scavengers, selenium and zinc, and a microsomal epoxide hydrolase-inducing agent, cis-stilbene oxide on the acute toxicity of T-2 toxin, a potent cytotoxic trichothecene, was investigated. Mice were pretreated daily for 3 consecutive days with either zinc sulfate (4.4 mg/kg, intraperitoneally [i.p.]), sodium selenite (1, 2, and 3 mg/kg i.p.) or cis-stilbene oxide (50 mg/kg i.p.). A full 24-hr after the final dosing with these agents, mice were given T-2 toxin (2, 2.5, or 3 mg/kg i.p.). The acute lethal toxicity of T-2 toxin (2.5 mg/kg) was reduced by administration of only sodium selenite (3 mg/kg) and cis-stilbene oxide (50 mg/kg). No significant effect on weight gain was observed.