An experimental investigation of the combustion of technical tetrachlorobenzene in a laboratory scale incinerator

An experimental study of the combustion of technical 1,2,3,4-tetrachlorobenzene has been carried out in conditions closely similar to those in incinerators of industrial hazardous wastes. A non-premixed flame fed by a fuel spray was stabilized in a reactor heated electrically. Measurements of axial and radial temperatures and species concentration profiles in well-defined conditions have been systematically repeated to specify the influence exerted by key parameters on the efficiency of the thermal degradation process. The reactor’s wall temperature was varied from 1223 to 1363 K. Air injection was distributed between axial and peripheral injectors to change the swirl intensity. Two fuel injectors have been compared to assess the influence of atomization efficiency. A methane-air pilot flame helped to anchor the flame and to decrease the overall Cl/H ratio. The latter was also decreased by addition of water vapor. Results show that conditions leading to a complete consumption of the fuel can be associated with very limited carbon conversion into CO₂ and chlorine conversion into HCl.     

Structural Test Approach for Embedded Analog Circuits Based on a Built-in Current Sensor

This paper presents a test method based on the analysis of the dynamic power supply current, both quiescent and transient, of the circuit under test. In an off-chip measurement, the global interconnect impedance associated with the chip package and the test equipment and, also, the chip input/output cells will complicate the extraction of the information provided by the current waveform of the circuit under test. Thus, the supply current is measured on-chip by a built-in current sensor integrated in the die itself. To avoid the effective reduction of the voltage supply, the measurement is performed in parallel by replicating the current that flows through selected branches of the analog circuit. With the aim of reducing the test equipment requirements, the built-in current sensor output generates digital level pulses whose width is related to the amplitude and duration of the circuit current transients. In this way the defective circuit is exposed by comparing the digital signature of the circuit under test with the expected one for the fault-free circuit. A fault evaluation has been carried out to check the efficiency of the proposed test method. It uses a fault model that considers catastrophic and parametric faults at transistor level. Two benchmark circuits have been fabricated to experimentally verify the defect detection by the built-in current sensor. One is an operational amplifier; the other is a structure of switched current cells that belongs to an analog-to-digital converter.     

Specific detection of viable Listeria monocytogenes in Spanish wastewater treatment plants by Fluorescent In Situ Hybridization and PCR

Listeria monocytogenes detection in wastewater can be difficult because of the large amount of background microbiota and the presence of viable but non-culturable forms in this environment. The aim of this study was to evaluate a Fluorescent In Situ Hybridization (FISH) assay combined with Direct Viable Count (DVC) method for detecting viable L. monocytogenes in wastewater samples, as an alternative to conventional culture methods. 16S rRNA sequence data were used to design a specific oligonucleotide probe. In order to assess the suitability of the method, the assays were performed on naturally (n = 87) and artificially (n = 14) contaminated samples and results were compared to those obtained with the isolation of cells on selective media and with a PCR method. The detection limit of FISH and PCR assays was 10⁴ cells/mL without enrichment and 10 cells/mL after enrichment. A total of 47 samples, including 3 samples from effluent sites, yielded FISH positive results for L. monocytogenes. Using DVC-FISH technique, the presence of viable L. monocytogenes cells was detected in 23 out of these 47 FISH positive wastewater samples. PCR and culture methods yielded 27 and 23 positive results, respectively. According to these results, FISH technique has the potential to be used as a sensitive method for the detection and enumeration of L. monocytogenes in environmental wastewater samples.     

The Cysteine Protease Giardipain-1 from Giardia duodenalis Contributes to a Disruption of Intestinal Homeostasis

In giardiasis, diarrhoea, dehydration, malabsorption, weight loss and/or chronic inflammation are indicative of epithelial barrier dysfunction. However, the pathogenesis of giardiasis is still enigmatic in many aspects. Here, we show evidence that a cysteine protease of Giardia duodenalis called giardipain-1, contributes to the pathogenesis of giardiasis induced by trophozoites of the WB strain. In an experimental system, we demonstrate that purified giardipain-1 induces apoptosis and extrusion of epithelial cells at the tips of the villi in infected jirds (Meriones unguiculatus). Moreover, jird infection with trophozoites expressing giardipain-1 resulted in intestinal epithelial damage, cellular infiltration, crypt hyperplasia, goblet cell hypertrophy and oedema. Pathological alterations were more pronounced when jirds were infected intragastrically with Giardia trophozoites that stably overexpress giardipain-1. Furthermore, Giardia colonization in jirds results in a chronic inflammation that could relate to the dysbiosis triggered by the protist. Taken together, these results reveal that giardipain-1 plays a key role in the pathogenesis of giardiasis.     

Study of the Electrochemical Behavior of N-Substituted-4-Piperidones Curcumin Analogs: A Combined Experimental and Theoretical Approach

The electrochemical behavior of N-methyl- and N-benzyl-4-piperidone curcumin analogs were studied experimentally and theoretically. The studied compounds present different substituents at the para position in the phenyl rings (-H, -Br, -Cl, -CF₃, and -OCH₃). We assessed their electrochemical behavior by differential pulse and cyclic voltammetry, while we employed density functional theory (DFT) M06 and M06-2x functionals along with 6-311+G(d,p) basis set calculations to study them theoretically. The results showed that compounds suffer a two-electron irreversible oxidation in the range of 0.72 to 0.86 V, with surface concentrations ranging from 1.72 × 10⁻⁷ to 5.01 × 10⁻⁷ mol/cm². The results also suggested that the process is diffusion-controlled for all compounds. M06 DFT calculations showed a better performance than M06-2x to obtain oxidation potentials. We found a good correlation between the experimental and theoretical oxidation potential for N-benzyl-4-piperidones (R² = 0.9846), while the correlation was poor for N-methyl-4-piperidones (R² = 0.3786), suggesting that the latter suffer a more complex oxidation process. Calculations of the BDEs for labile C-H bonds in the compounds suggested that neither of the two series of compounds has a different tendency for a proton-coupled electron transfer (PCET) oxidation process. It is proposed that irreversible behavior is due to possible dimerization of the compounds by Shono-type oxidation.     

Acute pancreatitis as a triggering factor for thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) constitutes a poorly understood multisystemic disease of vascular origin that may involve any organ by thrombotic occlusions of the small vessels. Treatment with plasmapheresis is the best therapeutic option at this present moment. Involvement of the pancreas is a well established feature of this disease, which has generally been interpreted as a consequence of pancreatic vascular compromise. However, there are a few cases in the literature in which the clinical signs of TTP developed well after the clinical and laboratory demonstration of acute pancreatitis (AP). Therefore, the possibility of pancreatic inflammation as a triggering factor of TTP may need to be considered. This cause-effect relationship between AP and TTP remains unclear. We report a patient with chronic pancreatitis presenting with two episodes of TTP, triggered by acute relapses of pancreatitis. TTP may, thus, constitute a hematological complication of AP. We discuss the pathophysiological aspects of this association, along with therapeutical options.     

Removal and processing inner ear specimens for morphological research on guinea pig ear

Seventy (70) dissections of temporal bones of grown-up guinea pigs were done by the AA. in order to get a suitable approach to obtain inner ear studies, aiming at a morphological investigation.     

Influence of the smoking habit in the surgery of inflammatory bowel disease

The smoking habit is a key factor in the development of inflammatory bowel disease (IBD), but little information exists as to the relationship between smoking habit, the need of surgery and its complications. OBJECTIVES: To investigate the relationship between smoking habit, the need of surgery, their complications and clinical recurrence after surgery in Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We studied a group of 62 patients (22 with UC and 40 with CD) with previous surgery. We analyzed the clinical and surgical characteristics of the disease. Smoking habit was established by a personal interview. This group of patients was compared with another control group of 202 patients (133 with UC and 69 with CD) with IBD without previous surgery. RESULTS: Smoking habit was similar between operated and non-operated patients for both UC (73% and 80% non-smokers) and CD (67% and 63% smokers) The number and type of complications after surgery were not related with smoking habit. In CD patients, although the recurrences did not depend on the smoking habit, they did occur earlier in smokers than in non smokers (83.6 +/- 21 vs 155 +/- 50 weeks, p = ns). CONCLUSIONS: The smoking habit does not seem to influence significantly the need of surgery and post surgical development of IBD, although in CD the smokers seems to present recurrence before non smokers.     

Viability assessment of lactic acid bacteria in commercial dairy products stored at 4 °C using LIVE/DEAD® BacLightTM staining and conventional plate counts

The viability of lactic acid bacteria (LAB) from commercial fermented milks was studied during storage at 4 °C. The enumeration of total viable bacteria was assessed using fluorescence microscopy. Plate counting on selective media was used to enumerate LAB. Using LIVE/DEAD® BacLight^TM viability staining, it was observed that bacterial counts decreased gradually after expiry dates, the number of viable bacteria remaining above 10⁶ bacteria g^?1 for all of the products. Viable cell counts estimated by plating onto selective media were lower than those obtained by direct microscopic counting. The viability of LAB contained in acid products decreased during their storage period at 4 °C. All products contain viable LAB ranging from 10⁸ to 10⁹ bacteria g^?1 and could be considered as probiotic, given that the recommended minimum number of probiotic bacteria in such food products is approximately 10⁷ bacteria mL^?1 product. The number of bifidobacteria in commercial fermented milks declared to contain bifidobacteria varied from 10⁴ to 10⁷ bacteria mL^?1. This study confirms the usefulness of fluorescent techniques for a rapid and accurate evaluation of bacterial viability in probiotic products.     

Optimizing offset times in Optical Burst Switching networks with variable Burst Control Packets sojourn times

In this paper, we consider the case of an Optical Burst Switching (OBS) network where the Switch Control Units (SCU) do not work at the peak rate. As a consequence, some Burst Control Packets (BCPs) will have to wait in queue to be processed, and then the BCP sojourn time will be variable. On the contrary, the optical burst does not leave the optical domain and the delay suffered is close to the propagation delay. Hence, chances are that the BCP arrives late to a given switch and, in that case, the optical burst will be dropped. We propose a Load-adaptive Offset Time algorithm (LOT) that takes into account the BCP variable sojourn time for the offset time calculation. The algorithm performs on-line calculation of the Discrete Fourier Transform (DFT) of the BCPs waiting time pdf. Our findings show that this procedure is very efficient both in terms of bandwidth usage and processing load. For example, considering a Gaussian service time for the BCPs, it turns out than less than 45 coefficients are necessary to calculate the offset time for a SCU utilization factor larger than 0.1.