Solid lipid nanoparticles affect microbial colonization and enzymatic activity throughout the decomposition of alder leaves in freshwater microcosms.

Solid lipid nanoparticles (SLNs) are used as carriers for drug delivery, and are high biocompatible and designed to endure in the host organism. Despite its current industrial production is low, many of these substances are available on the market, and much more are in the production pipeline. As a result, many of them will end in aquatic systems raising the question whether they can pose a risk to aquatic biota and the associated ecological processes. Microbial decomposers of plant litter, play a key role in forested streams being responsible for the energy flow between terrestrial and aquatic environments. Here, we investigated the effects of SLNs on alder leaf litter decomposition by aquatic microbes. Alder leaves were immersed in a stream of Northeast Portugal to allow microbial colonization before being exposed in microcosms of two types of SLNs at two concentrations for 42 days. Results showed that rates of leaf decomposition decreased with exposure to SLNs. Bacterial biomass was not inhibited by SLNs, and cultivable fungi densities remained constant (SLN-A) or increased (SLN-C) compared with control microcosms. The type and concentration of SLNs influenced differently the leaf colonization by fungi as well as fungal sporulation rate. These effects were accompanied by changes in the community extraenzymatic profile: the activities of alkaline phosphatase, acidic phosphatase, Naphthol-AS-BI-phosphohydrolase (P cycle) and lipases increased in the SLNs microcosms. This study provided the first evidence of the adverse effects of the release of SLNs to streams on leaf litter decomposition. Those effects seem to depend on the composition and concentration of SLNs, as well on the microbial target group, or enzyme. Thus, prior to massive industrial production of these nanomaterials, some measures should be taken to avoid environmental impact affecting the microbial communities responsible for detritus decomposition.

Transcylindrical cholecystectomy under local anesthesia plus sedation. A pilot study.

BACKGROUND AND STUDY AIM: The practice of laparoscopic cholecystectomy under local anesthesia is almost anecdotal. For 15 years we have been using a "transcylindrical cholecystectomy" technique for the treatment of cholelithiasis, cholecystitis, and choledocholithiasis. The present study was undertaken to assess the feasibility of transcylindrical cholecystectomy under local anesthesia through a prospective and longitudinal efficacy study. PATIENTS AND METHODS: Transcylindrical cholecystectomy is performed gas-free through a single cylinder 3.8 cm in diameter and 10.0 cm in length. In 60 patients suffering from cholelithiasis (mean age 52.6 years, range 31-83 years; men/women 13/47; body mass index 29.6 kg/m(2), range 24-44 kg/m(2)), transcylindrical cholecystectomy was planned and started under local anesthesia. Patients were reviewed 5 days after surgery; pain was assessed using a visual analog scale (VAS) and procedure satisfaction was assessed following completion of a patient questionnaire. RESULTS: Surgery was satisfactorily completed through the cylinder in all patients. In 13 patients (21.7 %) local anesthesia was converted to general anesthesia due to technical difficulties in 11 patients (two related to patient body volume), respiratory depression in one patient, and poor patient tolerance in one patient. Postoperative complications were: wound infection (n = 1, 1.7 %), wound seromas (n = 2, 3.3 %), and nausea (n = 3, 5 %). After surgery, only three patients experienced pain at rest with VAS values of 0.5, 1.5, and 2.9, respectively. All but two patients were discharged from hospital on the day of surgery, and all patients were satisfied with the procedure. CONCLUSIONS: Transcylindrical cholecystectomy under local anesthesia is a feasible technique that builds on the benefits of laparoscopic cholecystectomy, and confers an economic advantage and improved safety for patients.

Parity violation constraints using cosmic microwave background polarization spectra from 2006 and 2007 observations by the QUaD polarimeter.

We constrain parity-violating interactions to the surface of last scattering using spectra from the QUaD experiment's second and third seasons of observations by searching for a possible systematic rotation of the polarization directions of cosmic microwave background photons. We measure the rotation angle due to such a possible "cosmological birefringence" to be 0.55 degrees +/-0.82 degrees (random) +/-0.5 degrees (systematic) using QUaD's 100 and 150 GHz temperature-curl and gradient-curl spectra over the spectra over the multipole range 200