Biopolymer blends from hardwood lignin and bio-polyamides: Compatibility and miscibility

The compatibility of hardwood lignin (TcA)/bio-polyamide (PA) blends, prepared by melt compounding TcA with three different biobased polyamides, PA 1012, PA 1010 and PA 11 in a twin screw extruder has been studied. FTIR studies indicated the existence of physicochemical interactions between the TcA and polyamide. The melting temperatures of the blends were significantly reduced compared to the respective neat polyamides, which was attributed to the enhanced compatibility between the two components. The compatibility was also attributed to the increased glass transition (T_g) of the polyamide. Thermogravimetric studies, while not indicating any interaction during the processing stage, suggested that there was some during the thermal degradation stage, which assisted formation of carbonaceous residue. The addition of each polyamide to TcA considerably reduced its viscosity and enhanced its processability even at high lignin contents. Morphological analysis showed that heterogeneity for all the blends was quite uniform, although TcA domain sizes were considerably smaller (~0.5 μm) in the PA11 matrix compared to those in PA1010 and PA1012, suggesting better compatibility in the TcA/PA11 blends. This observation was consistent with the thermodynamic Gibbs' free energy values of the respective blends. Overall, the order of blend compatibility was TcA/PA11 > TcA/PA1010 > TcA/PA1012.

Scope of resident ophthalmology consultation service and patient follow-up rates at a level 1 trauma center in Brooklyn, New York

BACKGROUND

The purpose of this study was to investigate the most common reasons for urgent ophthalmology consultations in both the emergency room and inpatient settings at a large public hospital served by a busy ophthalmology residency program, and to track patient follow-up rates.

METHODS

We reviewed the medical records of all patients evaluated by the ophthalmology consultation service at Kings County Hospital Center from June 2003 to October 2005 using a retrospective hospital-based study design. We categorized emergency room patients and inpatients into traumatic and nontraumatic subgroups, and looked at diagnoses and patient demographics, as well as follow-up patterns for emergency room consultations.

RESULTS

In total, 743 patients were evaluated; 436 (59%) were emergency room patients and 307 (41%) were inpatients. Consultation for traumatic eye injury was provided for 399 patients (54%), accounting for 284 (65%) of the emergency room consults and 115 (37.5%) of the inpatient consults. The most common reason for inpatient consultation was to rule out ocular manifestations of systemic disease (57 patients, 29.7%), while the most common final diagnosis for trauma inpatient consultation was orbital wall fracture (59 patients, 51.3%). In total, 262 patients (60%) in the emergency room consultation group returned for follow-up care; 162 (57%) of the trauma patients followed up and 100 (66%) of the nontrauma patients followed up.

CONCLUSION

This study provides a comprehensive analysis of the eye conditions and follow-up rates evaluated by the ophthalmology service at Kings County Hospital Center. By evaluating the follow-up patterns of these patients, we may be able to alter patient counseling to increase patient compliance.