Synthesis, characterization, and biodegradation studies of new cellulose-based polymers.

New cellulose carbamates and cellulose acetate carbamates were prepared by classical addition reaction of isocyanates with alcohols. A Telomerization technique was used to make the grafted molecules strongly anchored and more hydrophobic. These molecules were grafted into cellulose and CA chains, respectively. The structures of the synthesized derivatives were confirmed using Nuclear Magnetic Resonance Spectroscopy, Fourier Transform Infrared and Thermogravimetric Analysis, and their solubility phenomenon was also established, and the carbamate derivatives showed better solubility compared to cellulose. Their ability to biodegrade was investigated, and it was concluded that Cell-P1 and CA-P1 derivatives are more biodegradable than the other samples. These results suggest that the resulting compounds can be used effectively in many useful industrial fields, for instance, eco-friendly food packaging, domains that use materials that are environmentally friendly and sustainable and the development of green chemistry.

Rheological and Electrical Study of a Composite Material Based on an Epoxy Polymer Containing Cyclotriphosphazene.

In this work, we have studied, formulated, prepared, and characterized the rheological and electrical behavior of a composite material based on an epoxy resin Diglycidyl Ether of Bisphenol A (DGEBA) reinforced with hexaglycidyl cyclotriphosphazene (HGCP). The epoxy system was cured with 4,4'-methylene dianiline (MDA). DGEBA-HGCP-MDA epoxy composite materials with reinforced HGCP which varied from 5% to 10% by weight were prepared by mixing in the molten state. The morphology was evaluated by SEM. The rheological behavior was studied using small deformation rheology. The electrical characterization was carried out with a frequency variation range from 1 Hz to 100 KHz at room temperature. These measurements revealed that the rheological and electrical behaviors strongly depend on the quantity of HGCP in the DGEBA matrix. The linear viscoelastic properties study reveals that the modulus of elasticity G' is dependent on the amount of HGCP present in the epoxy resin DGEBA. The capacitance-frequency measurements suggest a distribution of localized states in the band gap of the blends.

Prospective comparative study of the effectiveness of epidural morphine and ropivacaine for management of pain after spinal operations.

OBJECTIVE: Evaluation of the effectiveness of local application of morphine or ropivacaine for treatment of local and radicular pain after lumbar disc operations. Critical review of the literature about the possibilities of management of postoperative pain after spinal operations. METHODS: A total of 113 patients were randomly given 5 mg morphine sulfate (N=42), 10 ml 0,25% ropivacaine (N=42) or physiological NaCl solution (N=21) locally after lumbar disc operation before wound closure. Postoperative lumbar and radicular pain was scored by the patients from 0 to 10 and registered on the evening of the day of operation and on the 1., 2., 3., and 5. days. Mean pain numbers of the 3 groups have been compared, subdivided into local lumbar and in radicular pain. Our own results have been compared with the results of reports in the literature. RESULTS: In our own study the morphine group had less lumbar and less radicular pain on all 5 days than both of the two other groups. This difference was statistically significant on days 0, 1, 2, and 3. The ropivacaine group was on all days less effective than the morphine group, better than the placebo group on the operation and first day, but the difference against the placebo group was statistically not significant. CONCLUSION: Local application of 5 mg morphine sulfate is effective in prevention or reduction of postoperative lumbar and radicular pain after lumbar disc operations. Ropivacain is less effective. The routine application of epidural morphine at the end of spinal operations can be recommended. It also can be justified to try to prolong the morphine effect by mixing it into a paste as described by Needham and by Hurlbert, and to irrigate the operative field with ropivacaine at the end of the operation.

Intraventricular haemorrhage caused by aneurysms and angiomas.

More than 200 intraventricular haematomas (IVH) have been treated in the Homburg Neurosurgical University Clinic since computed tomography was available and facilitated the diagnosis. Among 200 consecutive cases, which are analysed and presented in this publication, there were 71 patients with subarachnoid haemorrhage (SAH)--58 of whom with angiographically and/or pathologically verified aneurysms--, and 21 cases with intraventricular angiomas. IVH without concomitant intracerebral haematoma (ICH) and without evidence of SAH is highly suggestive of intraventricular angioma. In our experience panangiography [if available digital subtraction angiography (DAS)] should be done as soon as possible in all cases of IVH. It is a precondition for early diagnosis and operative elimination of the source of bleeding, because the retrospective analysis of our material shows that rebleeding is by far the highest single risk factor in cases with IVH caused by aneurysms or angiomas. We therefore recommend early microsurgical occlusion of the aneurysms and exstirpation or intravascular embolisation of the angioma. The best survival rate (76%) was achieved in IVH cases caused by angiomas. In aneurysms with IVH the survival rate was 35%, in IVH caused by other diseases 37%. The worst prognosis occurs in SAH with IVH without proven aneurysm or angioma. The survival rate of this group was only 8%.