RESUMO
The porphyrinic metal-organic framework, PCN-222, exhibits anisotropic growth behavior to form nanorods and microrods with aspect ratios 3 < x < 94. Control of microrod aspect ratios has been demonstrated through the identification of several factors that dictate crystal growth, particularly the concentrations of a ligand, a modulator, and an exogenous base. An increase in the local concentration of a deprotonated ligand, which is proportional to the nucleation rate, is associated with smaller crystals, while increased modulator concentration leads to longer microrods. Addition of a deprotonating agent not only contributes to higher aspect ratios but also results in an improvement to particle dispersity. Here, we report acid-base co-modulation methods with difluoroacetic acid and triethylamine to effectively tune PCN-222 aspect ratios. A series of mechanisms is identified for the growth of PCN-222: (1) ligand deprotonation, (2) nucleation, (3) oriented attachment, (4) Ostwald ripening, and (5) dissolution-recrystallization. Time trials of co-modulated samples revealed three separate ripening growth events, with each resulting in larger and more monodisperse crystals. With an understanding of these crystal growth factors and mechanisms, the highest aspect ratio, non-templated metal-organic frameworks were synthesized (94 ± 9).
RESUMO
AIM: To explore whether routinely assessed biochemical markers tested on admission will predict 3 predefined adverse outcomes for hospitalized elderly patients: discharge to a long-term care facility, in-hospital mortality, and prolonged hospital length of stay (> 14 days). METHODS: A prospective observational study of elderly patients (aged ≥ 75 years) admitted to an acute-care geriatric ward over a 6-month period. Patients were assessed on admission and baseline characteristics were collected. Activities of daily living were assessed by the Barthel Index and cognitive function by the abbreviated mental test. Results from biochemical markers tested on admission were downloaded from the pathology laboratory database using patient details. Patients were followed-up with until discharge or in-hospital mortality. RESULTS: A total of 392 patients formed the study population. Mean (standard deviation) age was 83.2 (± 5.5) years and 283 (72%) patients were men. Thirty-eight (10%) patients were discharged to a long-term care facility, 134 (34%) had a prolonged hospital length of stay, and 33 (8%) died in the hospital. Results from testing 5 biochemical markers independently predicted in-hospital mortality: hypoalbuminemia (adjusted odds ratio [OR], 2.5; 95% CI, 0.9-6.7; P = 0.04), low total cholesterol level (adjusted OR, 2.9; 95% CI, 1.3-6.3; P = 0.01), hyperglycemia (adjusted OR, 2.9; 95% CI, 1.2-7.4; P = 0.02), high C-reactive protein level (adjusted OR, 4.2; 95% CI, 1.3-13.4; P = 0.01), and renal impairment (adjusted OR, 3.8; 95% CI, 1.7-8.7; P = 0.002). High C-reactive protein level independently predicted prolonged hospital length of stay (OR, 1.7; 95% CI, 1.1-2.9; P = 0.03). Hypoalbuminemia predicted discharge to a long-term care facility independent of confounding factors except for physical dysfunction (OR, 2.4; 95% CI, 1.1-5.1; P = 0.03). Significance was reduced after adjustment for Barthel Index score (OR, 1.9; 95% CI, 0.9-4.1; P = 0.08). CONCLUSION: Testing of routinely assessed biochemical markers on admission predicted adverse hospital outcomes for elderly patients. Their inclusion in a standardized prediction tool may help to create interventions to improve such outcomes.
