Comparison of 2-D Breath-Holding Half-Fourier Acquisition Single-Shot Turbo Spin-Echo Technique with Contrast Agents and 3-D Respiratory-Triggered Fast-Recovery Fast Spin-Echo Technique in MR Cholangiopancreatography

This study compares the quality of technical images in rendering the biliary tree magnetic resonance imaging (MRI) scans based on a three-dimensional (3-D) respiratory-triggered, fast-recovery, rapid spin-echo (3-D RT-FRFSE) technique with that of a 2-D contrast-enhanced breath-holding half-Fourier acquisition single-shot turbo spin-echo (2-D CE-BH-HASTE) technique. The MRI equipment used in this study was a 1.5 T unit (General Electric medical system, excite HD). A total of 30 patients (15 males and 15 females, mean age of 45 years) were examined. A 2-D CE-BH-HASTE technique was used to perform the scan using an interleaved acquisition at a small thickness within 15 s after injecting the contrast medium. The 3-D RT-FRFSE technique is referred to as a respiratory-triggered technique, where the scan is performed in a respiratory-triggered setting so that patients and MRI equipment can synchronize with the respiration. On quantitative analysis, the signal-to-noise ratio was obtained using the biliary tree and background noise, and the absolute contrast-to-noise ratio was obtained using the difference between the biliary tree and its adjacent tissue. On qualitative analysis, two radiologists and three experienced radiological technicians made an assessment based on the anatomic delineation, visibility of eight biliary trees and degree of image artifacts. The difference in image quality between the two techniques was assessed using a paired t-test and Wilcoxon signed-rank test. After quantitative analysis, the signal-to-noise and contrast-to-noise ratios for the common bile duct, common hepatic duct, intrahepatic bile duct, bile duct and pancreatic duct were found to be higher with the 3-D RT-FRFSE technique than with the 2-D CE-BH-HASTE technique. However, the excellent degree of the 3-D RT-FRFSE technique for the common bile duct, bile duct and pancreatic duct solely was significant (p < 0.05). The common hepatic duct showed an equivalent profile in the two techniques (p = 0.041). In addition, the 2-D CE-BH-HASTE technique showed a significant difference for the intrahepatic duct (p < 0.05). On qualitative analysis, the 3-D RT-FRFSE technique produced significant results with the delineation of eight biliary trees as well as anatomical delineation (p = 0.014, 0.039). However, there were no significant results regarding the artifacts of the images (p = 0.808). In conclusion, from the aspects of the quality of technical images, the 3-D RT-FRFSE technique can render the overall shape of biliary tree using a single test compared with the 2-D CE-BH-HASTE technique. However, the concomitant use of the two techniques would be useful for obtaining optimal information on the biliary tree.     

Friction and adhesion forces of Bacillus thuringiensis spores on planar surfaces in atmospheric systems

The kinetic friction force and the adhesion force of Bacillus thuringiensis spores on planar surfaces in atmospheric systems were studied using atomic force microscopy. The influence of relative humidity (RH) on these forces varied for different surface properties including hydrophobicity, roughness, and surface charge. The friction force of the spore was greater on a rougher surface than on mica, which is atomically flat. As RH increases, the friction force of the spores decreases on mica whereas it increases on rough surfaces. The influence of RH on the interaction forces between hydrophobic surfaces is not as strong as for hydrophilic surfaces. The friction force of the spore is linear to the sum of the adhesion force and normal load on the hydrophobic surface. The poorly defined surface structure of the spore and the adsorption of contaminants from the surrounding atmosphere are believed to cause a discrepancy between the calculated and measured adhesion forces.     

Nanoparticulate-induced toxicity and related mechanism in vitro and in vivo

In urban areas, the quantity of exhaust particles from vehicle emissions is tremendous and has been regarded as the main contributor to particulate matter (PM) pollution. Recently, the nano-sized PM on public health has begun to raise the attention. The increased toxicity of nanoparticulate can be largely explained by their small size, high airborne concentration, extensive surface area and high content of organic carbon and transition metals. We have attempted to address the toxicity of nano sized-particlulate matter by comparing various particulates including micro-SiO₂ (mSiO₂), nano-SiO₂ (nSiO₂), micro-TiO₂ (mTiO₂), and nano-TiO₂ (nTiO₂) in RAW264.7 cells and in vivo. The cell viability of all particulates decreased dose dependently. 24-h incubation with nSiO2 demonstrated apoptosis in RAW264.7 using Annexin-V binding immunofluorescent microscopy, but not in any other particulates. In vivo, cytotoxicity of nanosized was higher than micro-sized particulates. As higher the concentration of particulates, the more pulmonary injury and neutrophilic infiltration were observed in nano-sized than micro-sized particulates, respectively. Particularly, 5.0 mg/kg of mTiO₂ never shows any increase of neutrophile even with high cellularity of total cells and macrophages. From these results, we suggested that particulate-induced respiratory toxicity be influenced by component, size, and dose of particulates including the characteristic nature of the target cells in vitro and in vivo.     

The Fourier-finite element method for the Poisson problem on a non-convex polyhedral cylinder

We study the Poisson problem with zero boundary datum in a (finite) polyhedral cylinder with a non-convex edge. Applying the Fourier sine series to the equation along the edge and by a corner singularity expansion for the Poisson problem with parameter, we define the edge flux coefficient and the regular part of the solution on the polyhedral cylinder. We present a numerical method for approximating the edge flux coefficient and the regular part and show the stability. We derive an error estimate and give some numerical experiments.     

Experimental Investigation of Nozzle Exit Reflector Effect on Supersonic Jet

The present study describes an experimental work to investigate the effect of a nozzle exit reflector on a supersonic jet that is discharged from a convergent–divergent nozzle with a design Mach number of 2.0. An annular reflector is installed at the nozzle exit and its diameter is varied. A high-quality spark schlieren optical system is used to visualize detailed jet structures with and without the reflector. Impact pressure measurement using a pitot probe is also carried out to quantify the reflector’s effect on the supersonic jet which is in the range from an over-expanded to a moderately under-expanded state. The results obtained show that for over-expanded jets, the reflector substantially increases the jet spreading rate and reduces the supersonic length of the jet, compared with moderately under-expanded jets. The reflector’s effect appears more significant in imperfectly expanded jets that have strong shock cell structures, but is negligible in correctly expanded jet.     

Synthesis of Poly(2,5‐benzimidazole) for Use as a Fuel‐Cell Membrane

Summary: Poly(2,5‐benzimidazole) (ABPBI) was synthesized in a novel polymerization medium containing CH₃SO₃H and P₂O₅. 3,4‐Diaminobenzoic acid, a monomer for ABPBI, is soluble in the medium and the polymerization was therefore performed in a homogeneous state. It produced polymer fibers, thus simplifying the work‐up process. The membrane was cast directly from the polymerization mixture. Proton conductivities of the ABPBI membranes ranged from 0.02 to 0.06 S · cm⁻¹ above 100 °C, without humidification, and the tensile strength of the membrane was approximately 100 MPa.

Synthesis of ABPBI in a medium containing methanesulfonic acid and P₂O₅.     

Retro-Ene reaction. VI. Functionalization of 4,5-dihalopyridazin-6-ones using 1-acetyloxymethyl-4,5-dihalopyridazin-6-ones as the 1-O, 3-N, 5-O ene-adduct

Functionalization of 1-acetyloxymethyl-4,5-dihalopyridazin-6-ones via retro-ene reaction with some nucleophiles gave regioselectively only 5-halo-4-substitutedpyridazin-6-ones.     

An optimal order convergence for a weak formulation of the compressible Stokes system with inflow boundary condition

Summary. We formulate the compressible Stokes system given in (1.1) into a (new) weak formulation (2.1). A finite element method for this is presented. Existence and uniqueness of the finite element method is shown. An optimal error estimate for the numerical approximation is obtained. Numerical examples are given, showing its efficiency and rates of convergence of the approximate solutions that results from the discrete problem (3.1). Received October 20, 1996 / Revised version received January 21, 1999 / Published online: April 20, 2000     

Overexpression of Endogenous Xylose Reductase Enhanced Xylitol Productivity at 40 °C by Thermotolerant Yeast Kluyveromyces marxianus

Applied Biochemistry and Biotechnology - Xylitol is a valuable substance utilized by food and biochemical industries. NAD(P)H-dependent xylose reductase (XR)—encoded by the yeast KmXYL1...     

Effects of Sleep Deprivation on the Sedation of Pediatric Patients Undergoing MRI Examinations

Sedation is an essential factor for pediatric magnetic resonance imaging (MRI) procedure. A long-term failure of sedation has a detrimental effect on a 1 day test plan. Given this background, this study examined the effects of sedation using a sleep deprivation method in pediatric patients scheduled to undergo an MRI examination. The current study examined 54 patients (36 boys and 18 girls) with diseases, such as epilepsy, brain tumor, development delay, mental retardation, and cerebral infarction, who were treated at our medical institution from December 2009 to March 2010. The patients were classified into two groups: group A (n = 27) with sleep deprivation, and group B (n = 27) without sleep deprivation. The mean age of these patients was 4.2 years. Comparative analysis of groups A and B was performed to assess the success rate of pediatric sedation, the time elapsed until complete sedation had been achieved, and the frequency at which patients took Pocral syrup (chloral hydrate). In group A, patients were allowed to start sleep 1 hr later and were woken 1 hr earlier than their mean sleep time. According to this pretreatment, the rate of successful sedation, frequency of the administration of Pocral syrup, and the time elapsed until deep sedation had been achieved were measured. In group A, the rate of successful sedation was 100%, the mean time elapsed until deep sedation had been achieved was 23 min, and the mean frequency of Pocral syrup administration was 1.2 times. In addition, the proportions of patients who had achieved successful sedation after one-time use and two-time use of Pocral syrup were 77.8% and 22.2%, respectively. In group B, successful sedation was achieved in 89%, and the mean time elapsed until deep sedation was 39 min. The mean frequency of Pocral syrup administration was 1.5 times. The proportions of patients who had achieved successful sedation after one-time use and two-time use of Pocral syrup were 51.9% and 48.12%, respectively. The statistical significance was tested using a nonparametric analysis, Mann–Whitney U Test (p < 0.05). Other studies have reported that sleep deprivation had no significant effects. An actual comparison of the sleep-deprived and other patients showed that sleep deprivation affected the rate of successful sedation, the frequency of Pocral syrup administration, and the time elapsed until the patients were sedated. The rate of successful sedation was significantly higher in group A than in group B. The time elapsed until deep sedation had been achieved was also significantly shorter in group A than in group B. In addition, the frequency of Pocral syrup administration (administration dose) was significantly lower in group A than in group B. In conclusion, sleep deprivation increases the effectiveness of pediatric sedation in an MRI examination of pediatric patients and might assist in performing an MRI examination more efficiently in pediatric patients.