In colloidal methods, the morphology of nanoparticles (size and shape) as well as their stability can be controlled by changing the concentration of the substrate, stabilizer, adding inorganic salts, changing the reducer/substrate molar ratio, and changing the pH and reaction time. The synthesis of silver nanoparticles was carried out according to the modified Lee and Meisel method in a wide pH range (from 2.0 to 11.0) using citric acid and malic acid, without adding any additives or stabilizers. Keeping the same reaction conditions as the concentration of acid and silver ions, temperature, and heating time, it was possible to determine the relationship between the reaction pH, the type of acid, and the size of the silver nanoparticles formed. Obtained colloids were analyzed by UV-Vis spectroscopy and investigated by means of Transmission Electron Microscope (TEM). The study showed that the colloids reduced with citric acid and malic acid are stable over time for a minimum of seven weeks. We observed that reactions occurred for citric acid from pH 6.0 to 11.0 and for malic acid from pH 7.0 to 11.0. The average size of the quasi-spherical nanoparticles changed with pH due to the increase of reaction rate.
AbstractNanomaterials frequently possess unique and noticeably changed physical, chemical and biological properties compared to their macro scaled corresponding item. Utilization of nanoparticles habitually requires the construction of integrated chemical systems. Most popular of these are polymer-supported nanoparticles. In this review, we provide the reader with the last developments and breakthrough technologies concerning silver nanoparticles (AgNPs), one of the most comprehensively studied nanomaterials, considering the polymer types and processes used for the nanocomposite membranes preparation.
IntroductionThe selection of treatment for local recurrence in patients with non-small-cell lung cancer (NSCLC) depends on the possibility of performing a radical tumor resection, the patient's performance status, and cardiopulmonary efficiency. Compared with chemoradiotherapy, surgical treatment offers a greater chance of long-term survival, but results in completion pneumonectomy and is associated with a relatively high rate of complications.Aim of the studyAim of the study was to evaluate early and long-term results of surgery and conservative treatment (chemoradiotherapy) in patients with local NSCLC recurrence.Material and methodsBetween 1998 and 2011, 1697 NSCLC patients underwent lobectomy or bilobectomy at the Department of Thoracic Surgery in Poznań. Among them, 137 patients (8.1%) were diagnosed with cancer recurrence; chemotherapy or chemoradiotherapy was provided to 116 patients; 21 patients (15.3%) were treated with completion pneumonectomy. The median time from primary surgery to recurrence was 13.4 months. No metastases to N2 lymph nodes were observed among the patients undergoing surgery; in 7 patients N1 lymph node metastases were confirmed.ResultsThe rate of complications after surgery was significantly higher in comparison with conservative therapy (80.9% vs. 48.3%). Patients treated with surgery were most likely to suffer from complications associated with the circulatory system (80.9%), while hematologic complications were dominant in the group undergoing oncological treatment (41.4%). There were no perioperative deaths after completion pneumonectomy. The age of the patients was the only factor which significantly influenced the incidence of complications in both groups of patients. Analysis of the survival curves demonstrated statistically significant differences in survival between the groups treated with surgery, chemoradiotherapy, and chemotherapy (p = 0.00001). Five-year survival probability was significantly higher among patients treated surgically as compared to patients undergoing systemic therapy.ConclusionsDespite the significant rate of postoperative complications (mostly circulatory), the long-term results of the surgical treatment of local NSCLC recurrence are more favorable than those achieved with chemoradiotherapy. The success of surgical treatment is conditioned on the exclusion of metastasis in N2 lymph nodes.
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