Packed bed compression visualisation and flow simulation using an erosion-dilation approach.

X-ray computed tomography has been demonstrated to be capable of imaging 1 mL (5 mm diameter, 50 mm height) chromatography packed beds under compression, visualising the 3D structure and measuring changes to geometry of the packing. 1 mL pre-packed columns did not exhibit any structural changes at vendor specified flow rate limits, however cellulose beds did compress at higher flow rates that were imaged before, during and after flow. This was used to visualise and quantitate changes to porosity, tortuosity and permeability based on simulation of flow through the packed bed structure using the imaging data. When using a high flow rate it was found that a decrease in porosity could be measured during compression before reverting after flow had ceased, with corresponding changes to tortuosity and permeability also occurring. X-ray CT imaging of packed beds and individual beads exposed to foulant-rich process streams resulted in considerable image quality loss, associated with residual biological material. In order to address this, digital processing using an erosion-dilation method was applied at bead and bed scales to computationally alter the porosity by adding or removing material from the existing surface to calculate the impact upon tortuosity factor. The eroded and dilated bead volumes of agarose, cellulose and ceramic materials were used to simulate diffusivity whilst mimicking internal bead pore constriction and blocking mechanisms.

Analysis in Drosophila melanogaster of the interaction between sex combs reduced and extradenticle activity in the determination of tarsus and arista identity.

Sex Combs Reduced (SCR) activity is proposed to be required cell nonautonomously for determination of tarsus identity, and Extradenticle (EXD) activity is required cell autonomously for determination of arista identity. Using the ability of Proboscipedia to inhibit the SCR activity required for determination of tarsus identity, we found that loss-of-EXD activity is epistatic to loss-of-SCR activity in tarsus vs. arista determination. This suggests that in the sequence leading to arista determination SCR activity is OFF while EXD activity is ON, and in the sequence leading to tarsus determination SCR activity is ON, which turns EXD activity OFF. Immunolocalization of EXD in early third-instar larval imaginal discs reveals that EXD is localized in the nuclei of antennal imaginal disc cells and localized in the cytoplasm of distal imaginal leg disc cells. We propose that EXD localized to the nucleus suppresses tarsus determination and activates arista determination. We further propose that in the mesodermal adepithelial cells of the leg imaginal discs, SCR is required for the synthesis of a tarsus-inducer that when secreted acts on the ectoderm cells inhibiting nuclear accumulation of EXD, such that tarsus determination is no longer suppressed and arista determination is no longer activated.

Outpatient termination of early pregnancies using syringe and plastic cannula.

PIP: Experience with outpatient termination of early pregnancies (menstrual regulation) using a Milex cannula-curette is summarized. 543 women not more than 8 weeks pregnant were aborted with a 50-ml syringe and a Karman-type cannula-curette on an outpatient basis. Paracervical block analgesia and atropine were given intravenously during the procedure to minimize vagal reactions. .9% (n=5) of pregnancies were missed by the procedure, and 2.4% (n=13) of the procedures were incomplete. Only 1 instance of postoperative sequelae was found, and that was a pelvic infection. 4.9% of the women were not pregnant at the time of procedure, and the preoperative procedure was modified to include routine urine pregnancy testing before menstrual regulation to reduce the percentage of nongravid. The procedure was well-tolerated and inexpensive.^ieng