Development of co-continuous morphology in blends of thermoplastic starch and low-density polyethylene.

This study focuses on the morphology development in blends of thermoplastic starch (TPS) with Low Density Polyethylene (LDPE) in the 40 to 80 TPS wt% concentration range. The effect of glycerol and water content on TPS rheology and the subsequent morphology development after blending with LDPE of various viscosity levels was investigated. The TPS/LDPE viscosity ratio was modified either by increasing the TPS plasticization or by proper selection of the LDPE grade. Particular attention was given to the effect of TPS humidity on viscosity and therefore humidity levels were carefully measured by Karl Fisher titration prior to rheometry. It was found that the viscosity of the TPS was highly dependent on the plasticizer level and that the flow activation energy of TPS was around 3 times higher than that of LDPE. Different types of blend morphologies were achieved from dispersed to co-continuous. It was found that the co-continuous structure appeared at higher TPS concentration when increasing the TPS/LDPE viscosity ratio.

Complex melting of semi-crystalline chicory (Cichorium intybus L.) root inulin.

When concentrated solutions (30-45% by weight) of inulin (degree of polymerization 2-66, number average degree of polymerization 12) are cooled at 1 degree C/min or 0.25 degree C/min from 96 degrees C to 20 degrees C, suspensions of semi-crystalline material in water are formed. A thermal nucleation process was detected by optical microscopy: the 8-like shaped crystallites resulting from primary nucleation at higher temperature are larger than those resulting from secondary nucleation at lower temperature. Differential scanning calorimetry (DSC) thermograms display melting profiles with three to four partly overlapping endotherms that vary as a function of concentration, cooling rate during crystallization and storage time at 25 degrees C of the crystallite suspension. Recrystallization during melting was observed. The wide-angle X-ray scattering patterns of the samples at 25 degrees C correspond to those of the hydrated crystal polymorph. The structural changes during melting indicated the existence of a single crystal polymorph throughout melting. A periodicity of 95 A, arising from alternating regions of different electron density, is detected in the small angle X-ray scattering patterns at 25 degrees C. The stepwise increase of the long period upon heating is related to the existence of two types of lamellar stacks: one with a higher long period, resulting from the primary nucleation and thus crystallized at high temperature, and a second one with a smaller long period, formed by crystallization at lower temperature. The lamellae formed at low temperature melt at a lower temperature than those formed at high temperature, explaining the existence of the two DSC-endotherms.

Ovarian cyst fenestration via laparoscopy.

During laparoscopy for diagnosis or sterilization a small series of ovarian cysts was managed by aspiration only or by aspiration, biopsy and fenestration. If the enumerated criteria for cyst selection are followed, the technique described safely permits aspiration and provides data for a therapeutic plan. This method suggests a lower incidence of cyst recurrence.

Laparoscopy at a community hospital: an analysis of 4,300 cases.

In a 54-month period, a community hospital developed a laparoscopic program that has offered 4,361 patients the benefits of laparoscopic diagnosis, sterilization and ancillary intraabdominal procedures. It has also provided training for residents and beginning laparoscopists and additional income for the hospital. The evolution in technique and method are reviewed. A statistical compilation of all cases is presented. Among 1,924 bipolar procedures in this series, no method-related complications were observed.

Female outpatient sterilization using bipolar coagulation.

PIP: Laparoscopy by electrocoagulation requires some formal training because the margin of error in selftaught laparoscopy is great. Pertinent electrical information is reviewed to acquaint physicians with a system mandatory for patient safety and the physician's medicolegal protection. The bipolar electrocoagulation method offers great safety compared with the unipolar method, and Kleppinger bipolar forceps facilitate sterilization and ancillary procedures. Omission of division and resection after tubal coagulation reduced the number of peritoneal fistulae and, therefore, procedural failures. The possibility of ectopic pregnancy remains. Opposition to using electricity in the abdomen occurred because of the possibility of thermal bowel injury. With the bipolar components described here it is virtually impossible to acquire a bowel burn unless a portion of the bowel is mistakenly treated. Since the inception of this bipolar program, no forceps-related complications have occurred.^ieng