Short communication: Electrospinning of casein/pullulan blends for food-grade applications.

Electrospinning is a complex process that produces fibers with diameters on the micrometer or nano-scale from an electrified jet of a polymer solution. The objective of this study was to create electrospun fibers for food use from aqueous solutions of calcium (CaCAS) or sodium caseinate (NaCAS). Fibers were not formed from electrospinning of solutions of either caseinate (CAS) at 50 °C, but were formed from blends of either CAS solution with aqueous solutions of the food-grade polysaccharide, pullulan (PUL), when using mass ratios from 2:1 to 1:4 of PUL/CAS. The CAS in the spinning solutions ranged from 3 to 15% (wt/wt) and the PUL ranged from 5 to 15% (wt/wt). The PUL/CaCAS 1:2 fibers showed the lowest fiber diameter sizes (FDS) of 172 ± 43 nm, as determined by scanning electron microscopy, and were smaller in size than fibers electrospun from 15% (wt/wt) PUL solution. The PUL/NaCAS solutions were more viscous and formed fibers with occasional branching and less uniform FDS at higher NaCAS contents. Reductions in NaCAS in these solutions reduced viscosity and improved jet stabilities with consequent improvement in fiber morphology leading to more uniform FDS. Fibers with less defects and more homogeneous FDS were formed from PUL/CaCAS blends with more CaCAS, showing that each CAS interacted differently with PUL and formed the best fibers at different solution conditions. Calcium bridging may also underlie the anomalous behavior of the PUL/CaCAS blends by forming crosslinks with the phosphoserine residues, further enabling chain entanglements for fiber formation. The PUL/NaCAS fibers tended to be larger than the PUL/CaCAS fibers, which may also be due to other factors such as solution surface tension and conductivity, which also affect fiber quality and size. The shear viscosities at 100 s(-1) of the solutions producing fibers were within the range of 0.07 to 0.16 Pa/s, with the smallest standard deviations in FDS noted for solutions with viscosities within about 25% that of PUL. This is the first example of caseinate fibers prepared using a food-grade carrier rendering a product with potential use in food and packaging applications.

Emergent chemical mapping at atomic-column resolution by energy-dispersive x-ray spectroscopy in an aberration-corrected electron microscope.

Chemical mapping at atomic-column resolution by energy-dispersive x-ray spectroscopy in a spherical aberration-corrected scanning transmission electron microscope (STEM) has been demonstrated for the 1.47-A dumbbell structure in InGaAs. The structural imaging and the chemical information in the two-dimensional map are directly correlated. Comparisons with the other existing mapping techniques of STEM in conjunction with electron energy-loss spectroscopy were discussed from aspects of ionization interactions.

Prolonged neuromuscular block with mivacurium in a patient with cholinesterase deficiency.

Mivacurium is a short-acting, nondepolarizing neuromuscular blocking agent hydrolyzed by plasma cholinesterase. Because it allows fast recovery, it is a commonly used muscle relaxant for patients undergoing short surgical procedures. We report the case of a 5-year-old boy who underwent outpatient inguinal herniorraphy and developed unexpected prolonged neuromuscular block after the use of mivacurium. He required mechanical ventilation support in the intensive care unit because he could not attain adequate muscle power 1 hour after termination of anesthesia; the muscular paralysis persisted for 5 hours after the bolus dose of 0.3 mg/kg mivacurium. Subsequent investigation revealed an extremely low plasma cholinesterase concentration (115 U/L), and this was later determined to be a congenital condition. This is the first reported case of cholinesterase deficiency diagnosed as a result of general anesthesia in Taiwan.

Ventricular tachycardia after oxytocin injection in patients with prolonged Q-T interval syndrome--report of two cases.

Oxytocin is widely used in obstetric settings to stimulate uterine contraction and prevent postpartum hemorrhage. Its adverse effects which include transient hypotension and increase heart rate could be life-threatening in patients with fixed cardiac output or hypotension resulting from hemorrhage. We reported two cases suspected to have preexisting prolonged Q-T interval syndrome (PQTS) who developed ventricular tachycardia immediately after intravenous injection of oxytocin. Anesthetic management of and use of oxytocic agents in patients with PQTS were discussed.

The magnetoelectric effect in Ni-Fe alloy/ZnO nanorod array composites.

Ni-Fe alloy/ZnO nanorod composites were fabricated and the magnetoelectric effect was demonstrated. The ZnO and Ni-Fe alloy serve as the piezoelectric phase and the magnetostrictive phase in the nanocomposite, respectively. Since the nanorod structure possesses the inherent nature of a large surface-to-volume ratio, it greatly enhances the interplay between the piezoelectric and magnetostrictive coupling. Besides, the substrate clamping effect can be avoided. Our newly devised composite therefore provides a different species for magnetoelectric applications. It is interesting that the magnetoelectric voltage coefficient determined by the direct measurement method can reach a value as high as 0.48 mV cm(-1) Oe(-1).

Airway obstruction in general anesthesia--two different episodes in the same patient: case report.

The case of a patient with Apert's syndrome (acrocephalosyndactyly) who had a tracheostomy tube and who encountered two different episodes of critical airway obstruction during two different general-anesthetic procedures for craniofacial surgery is reported. The first episode, at the age of four, involved occlusion of the uncuffed tracheostomy tube by a blood clot, which might have come from the surgical field of the maxillary Le-Fort III advancement procedure. The second episode was encountered during his emergence from the general anesthesia of a degloving midface osteoplasty and a maxillary Le-Fort I osteotomy procedure 3 years later. Although a cuffed armored tube had been inserted through the tracheostoma to prevent aspiration of blood from the surgical field, the armored tube was plugged by a piece of granulation tissue that might have been dislodged from the peri-stomal area. Factors that lead to tracheostomy tube obstruction, their clinical features and preventive measures are discussed. We believe that being alert to changes in the airway pressure, the ventilation pattern, and the hemodynamic status is necessary during the administration of general anesthesia. Precautions should be taken at all times, particularly for patients with a tracheostomy.

Image display for collision avoidance of radiation therapy: treatment planning.

Patient treatment in a medical linear accelerator is characterized by many angular and translational movements of the gantry and couch. The direction and orientation of each treatment beam is specified by a set of gantry, turntable, and collimator angles. It is possible that some selected treatment field configurations will result in gantry/couch or gantry/patient collisions that remain undetected during the treatment planning process. In this work, a digital camera has been used to record all the workable gantry/ patient set-up images, and a Windows programming language is used to edit and display these images on a personal computer for the treatment planner to screen the treatment plans. These graphical displays enable the planner to be aware of any potential collision hazards by an actual visualization of each selected gantry/turntable or gantry/patient angle configuration.