Techniques applied to the study of microbial impact on building materials

This paper presents various techniques for materials characterisation in relation with the question of microbial impact. Application examples of some of these techniques are described as well as the respective results obtained by researchers working in this field. Additional readings are also reported.     

Pyrolysis of brown coal under different process conditions

Pyrolysis tests were performed under laboratory conditions, simulating possible processes in the burning of brown coal mines. These tests focused on gaseous products of thermal decomposition of coal and how their concentrations changed depending on pyrolysis temperature. Results obtained can help to quantify the contributions of particular gases to overall explosiveness of a gaseous mixture and can explain the process of explosive gas release during conflagration.     

Prospective biochemical and scintigraphic evaluation of autografted normal parathyroid glands in patients undergoing thyroid operations

Recent reports suggest that oral choline supplement may alter the cerebral choline/creatine (Cho/Cr) ratio and might be used to treat neurodegenerative disorders of cholinergic transmission. Using both 1H and 31P MRS, we reexamined the Cho/Cr ratio and quantified cerebral choline and its major constituents: phosphoethanolamine (PE), phosphorylcholine (PC), glycerophosphorylethanolamine (GPE), and glycerophosphorylcholine (GPC). In the four brain locations examined, no significant increases in Cho/Cr, [Cho], or in its major constituents were found in response to an oral challenge of 50 mg/kg of choline bitartrate. Oral choline did not significantly affect human cerebral metabolism in the short term.     

A numerical method for determining the kinetic constants of gas–liquid metal interactions in N–Ni–20Cr and N–ASTM F-75 alloy systems

In gas–liquid interaction systems, under non-equilibrium degassing conditions, the rate of a particular process often follows a mixed control regime where serial-acting mechanisms affect the global rate of the process and, therefore, the determination of real kinetic constants is difficult. In this paper a numerical method for determining these kinetic constants is presented and applied to the cases of denitrogenation of liquid Ni–20Cr alloys at 1873 K and nitrogen absorption in liquid ASTM F-75 alloys at 1773 and 1823 K. The results showed that interaction kinetics of nitrogen with both alloys was limited by both first and second order mechanisms. This results permit manufacturing engineers to act on the process parameters in order to obtain the nitrogen content that allows the best performance of mechanical parts.     

Anesthesia for morbidly obese patients

Bariatric surgery is the most effective method for treating patients with morbid obesity, and participation of the anesthesiologist in the treatment of these patients is more and more frequent. Therefore it is important for anesthesiologists to be familiar with anatomic and physiologic implications and the pharmacologic changes associated with obesity, so they can offer optimal perioperative treatment. The present study describes a series of 37 patients with an average body mass index of 50.3 kg/m2 who underwent bariatric surgery in a third-level teaching hospital in Mexico City. Preoperative assessment, airway management, perioperative treatment, and the incidence of complications are analyzed. We found a high frequency of associated diseases, among which diabetes mellitus and systemic arterial hypertension were the most prominent. Cardiorespiratory complications such as obstructive sleep apnea syndrome and obesity-hypoventilation syndrome were particularly frequent (16.2% and 22.0%, respectively). Both general anesthesia and mixed anesthesia (peridural block plus light general anesthesia) were employed. The incidence of complications related to perioperative and anesthetic management was low. We discuss and propose protocols for the evaluation and management of airway and associated cardiorespiratory complications.     

The use of water and ice with bactericide to prevent onboard and onshore spoilage of refrigerated megrim (Lepidorhombus whiffiagonis)

This study investigates the effectiveness of ozonated water and flake ice (combined Petfrost system) to increase the quality and stability of fresh megrim on fishing boats. The captured fish were washed, placed in plastic boxes, covered with flake ice and refrigerated at 2 °C for up to 2-weeks onboard and, thereafter, for 11 days onshore. The experiments employed sterile, filtered and ozonated water at a concentration of 2 ppm for washing the fish and making the flake ice. The results are compared with samples from a traditional treatment consisting of water and flake ice of marine origin. Fish were caught in four different hauls, which took 14, 12, 8 and 3 days in being landed. Subsequently, fish were stored for 1, 5, 7 and 11 days at 3 °C. The different treatments were evaluated using sensory, microbiological and chemical techniques. Fish treated with ozone always showed the best quality. Megrim treated with ozone was still suitable for consumption after 14 days on board, and megrim stored for 12, 8 and 3 days on board could be stored for a further five days in the ice state once landed with an acceptable quality. In contrast, control fish were not suitable for consumption if stored for longer than three days on board.The results indicate that treatment with water and ice flakes made from sterile and ozonated water maintains the quality of fresh megrim onboard fishing boats and upon arrival onshore.     

Efficacy of citric acid against Listeria monocytogenes attached to poultry skin during refrigerated storage

The aim of this study was to evaluate the effect of citric acid washing on the growth of Listeria monocytogenes on poultry legs stored at 4 °C for 8 days. Fresh inoculated chicken legs were dipped into either a 0.052, 0.104 or 0.156  m citric acid solution for 5 min or distilled water (control). Surface pH values, sensorial characteristics and L . monocytogenes , mesophiles and psychrotrophs counts were evaluated. Legs washed with 0.156  m citric acid for 5 min showed a significant ( P  < 0.05) inhibitory effect on L . monocytogenes compared with control legs, being about 1.55 log units lower in the first ones than in control legs after 1 day of storage. Treatments with 0.156  m citric acid reduced bacterial growth and preserved reasonable sensorial quality after storage at 4 °C for 8 days.