Biocompatibility and cutaneous reactivity of cellulosic polysaccharide film in induced skin wounds in rats

The development of a skin substitute suitable for immediately performing the function of the lost dermis and epidermis could result in a positive impact on the treatment of patients with extensive skin lesions. A biopolymer film was applied to skin wounds to investigate the biocompatibility and cutaneous reaction and to test its activity as a mechanical barrier and conductor in the healing process. Forty Wistar rats of both sexes were used in the present study. Two excisions were performed in the dorsal part of the skin flaps. The polysaccharide film was applied over one of the incisions and other incision was washed with saline. The time spent for complete healing of both lesions was virtually the same in both groups, during 21 days of observation. The film remained attached to the bed of the exposed wound for an average period of 6 days. There were no statistically significant differences with regard to lesion measurement area at assessment times of 2nd, 7th and 14th postoperative days. At day 21, the scar area showed a significant difference (0.0229). After 40 days, all wounds were completely healed. No statistically significant differences were found between the histological parameters assessed in the experimental and control groups. The cellulosic polysaccharide film integrated well with the tissue showing high biocompatibility and low skin reactivity.     

Cold Plasma Modification Effects on the Water Flow through Sintered UHMWPE Membranes

Natural rubber latex and various concentration of natural antioxidant were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The aqueous extraction of Diospyros peregrina was used as natural antioxidant. It was found that the addition of different concentration of natural antioxidant into natural rubber latex improve the aging property of the film. Decreasing in tensile strength of rubber film with 10 phr natural antioxidant and 15 kGy radiation dose after 24 hours aging at 100°C was 9.34% compared to 13.89% for film without natural antioxidant. The tensile strength, tear resistance and modulus at 500% elongation of the rubber film were found to be optimum at 15 kGy radiation dose and with 10 phr natural antioxidant. Elongation at break, permanent set and swelling ratio decreases with the increasing absorbed radiation dose as well as the concentration of the natural antioxidant.     

Conditioned and unconditioned fear organized in the inferior colliculus are differentially sensitive to injections of muscimol into the basolateral nucleus of the amygdala.

Chemical stimulation of the inferior colliculus (IC) with semicarbazide--an inhibitor of the gamma aminobutyric acid synthesizing enzyme--functions as an unconditioned stimulus in the conditioned place aversion test (CPA), and electrolytic lesions of the basolateral amygdala (BLA) enhance the aversiveness of the IC stimulation. This study examined the effects of inactivation of the BLA with muscimol on the conditioned and unconditioned fear using semicarbazide injections into the IC of rats subjected to conditioned (CPA) or unconditioned (open field) fear tests. In both tests, the rats were injected with semicarbazide or saline into the IC and muscimol or saline into the BLA. Muscimol decreased the CPA and increased the unconditioned fear elicited by IC injections of semicarbazide. These findings indicate that distinct modulatory mechanisms in the BLA are recruited during the conditioned and unconditioned fear triggered by IC activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of chromate quenching and chloride contamination level on the performance of the painted hot-dipped galvanized steel (duplex system)

The influences of the chromate quenching step and the surface chloride contamination levels of galvanized steel on the performance of duplex systems were studied. Steel panels were galvanized in a commercial steel bath adopting three different postdipping procedures. A comparative study of the galvanized steel, both painted and nonpainted, was performed by electrochemical techniques. It was verified that the chloride contamination level of the galvanized steel surfaces is the main cause of duplex system failures. An explanation for the influence of the chromate quenching on the performance of duplex systems was presented.     

Equations to predict precipitation onset and bubblepoint pressures of asphaltenic reservoir fluids

A set of algebraic equations to predict upper onset‐of‐precipitation and bubble‐point pressures of asphaltene‐containing reservoir fluids in wide temperature ranges are proposed. In developing the equations, laboratory data of 11 Mexican and 12 more live oils have been analyzed, and a correlation of these data with temperature has been found. A modified least‐squares regression method has been used to develop two versions of the proposed equations. In one version, a single pressure/temperature data point is required to predict the entire onset/bubble‐point curves at any temperature. For oils with no experimental precipitation data available at all, a second version of the proposed expressions employs standard chromatographic data of the reservoir fluid to provide a reasonable prediction. The average absolute deviations in calculated onset and bubble‐point pressures by the proposed equations are 2.53 and 0.45MPa by the one‐point correlations, respectively, and 3.96 and 1.62 MPa by the compositionally‐based correlations, respectively. The developed expressions are simple and can be used to provide reasonable predictions of upper onset and bubble‐point pressures of asphaltenic live oils in cases where laboratory data are scarce. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Predominance and characteristics of Burkitt lymphoma among children with non-Hodgkin lymphoma in northeastern Brazil

The purpose of this paper was to define the histologic distribution, clinical features, and treatment response of childhood non-Hodgkin lymphoma (NHL) in northeastern Brazil. We reviewed medical records and histopathologic studies of 98 children treated for NHL from 1980 to 1987 at a major pediatric cancer center in Recife, Brazil. Treatment outcome was evaluated in relation to tumor burden (stage and serum LDH) and type of therapy (LSA2L2 vs other multiagent chemotherapy). There was a striking predominance of the small noncleaved cell (Burkitt) subtype, which occurred in 92 of the 98 children and adolescents diagnosed with NHL. Subsequent analyses focused on these patients. The majority (n = 84) had advanced (stage III/IV) disease at diagnosis. The abdomen was the most common site of disease (84 cases); jaw involvement was rare (three cases). Five-year event-free survival (excluding treatment refusals) was significantly better for patients with limited vs advanced stage disease (75 +/- 14% vs 42 +/- 6%; P < 0.04). Elevated serum LDH (>500 U/l) was associated with a poorer outcome (P = 0.008). The type of chemotherapy did not affect EFS (P = 0.95). Only 39% of patients are long-term survivors, reflecting the high rate of septic deaths (25% of patients) and parental refusal/abandonment of therapy (10%). Epstein-Barr virus (EBV) was detected in tumor cells from eight of the 11 cases studied. In clinical presentation, these cases resemble sporadic Burkitt lymphoma, yet in their apparent responsiveness to LSA2L2 therapy and association with EBV, they do not. Childhood NHL in northeastern Brazil is predominantly of the Burkitt subtype, and is associated with clinical features that appear to distinguish it from the endemic and sporadic forms of this tumor. These cases may represent a third or intermediate subtype of Burkitt lymphoma.     

Challenges and opportunities for productivity improvement studies in linear,repetitive, and location-based scheduling

Despite theoretical advancements in alternative project planning methods the extent of their practical implementation varies strongly; it has been limited especially in the US construction industry. The family of linear, repetitive, and location-based scheduling techniques holds significant but barely substantiated promise by containing multiple variables of interest for integrated analysis and optimization. Yet it is necessary to provide empirical evidence that using such techniques can improve productivity to increase credibility and acceptance by practitioners, because claims of conceptual superiority are only sporadically supported with detailed measures. An analysis is performed to identify relevant decision-making variables, extract challenges that currently limit the corpus of quantitative productivity studies on alternative scheduling to its insufficient size, and reveal opportunities to expand it in breadth and depth. Variables are categorized by their relevance to time, activity, resource and location, as well as the managerial approach. Challenges include the diverse definitions of productivity itself, issues related to achieving generalizability, and the detailed steps of data collection, preparation, and analysis. Opportunities include the guidance from existing but rare studies and well-established research methods such as case studies that can be applied. This is illustrated with a sample project of a high-rise apartment building in Brazil. If alternative methods can be proven to be measurably better for specific applications, there might be a paradigm shift from merely defaulting to traditional but problematic network-based scheduling toward consciously choosing the planning method based on its potential benefits for a project.