Evaluation of carbon dioxide mass transfer in raceway reactors for microalgae culture using flue gases

Mass transfer of CO2 from flue gas was quantified in a 100m(2) raceway. The carbonation sump was operated with and without a baffle at different liquid/gas ratios, with the latter having the greatest influence on CO2 recovery from the flue gas. A rate of mass transfer sufficient to meet the demands of an actively growing algal culture was best achieved by maintaining pH at ∼8. Full optimisation of the process required both pH control and selection of the best liquid/gas flow ratio. A carbon transfer rate of 10gCmin(-1) supporting an algal productivity of 17gm(-2)day(-1) was achieved with only 4% direct loss of CO2 in the sump. 66% of the carbon was incorporated into biomass, while 6% was lost by outgassing and the remainder as dissolved carbon in the liquid phase. Use of a sump baffle required additional power without significantly improving carbon mass transfer.

Comprehensive model of microalgae photosynthesis rate as a function of culture conditions in photobioreactors

In this paper, the influence of culture conditions (irradiance, temperature, pH, and dissolved oxygen) on the photosynthesis rate of Scenedesmus almeriensis cultures is analyzed. Short-run experiments were performed to study cell response to variations in culture conditions, which take place in changing environments such as outdoor photobioreactors. Experiments were performed by subjecting diluted samples of cells to different levels of irradiance, temperature, pH, and dissolved oxygen concentration. Results demonstrate the existence of photoinhibition phenomena at irradiances higher than 1,000 μE/m(2) s; in addition to reduced photosynthesis rates at inadequate temperatures or pH-the optimal values being 35 °C and 8, respectively. Moreover, photosynthesis rate reduction at dissolved oxygen concentrations above 20 mg/l is demonstrated. Data have been used to develop an integrated model based on considering the simultaneous influence of irradiance, temperature, pH, and dissolved oxygen. The model fits the experimental results in the range of culture conditions tested, and it was validated using data obtained by the simultaneous variation of two of the modified variables. Furthermore, the model fits experimental results obtained from an outdoor culture of S. almeriensis performed in an open raceway reactor. Results demonstrate that photosynthetic efficiency is modified as a function of culture conditions, and can be used to determine the proximity of culture conditions to optimal values. Optimal conditions found (T = 35 °C, pH = 8, dissolved oxygen concentration <20 mg/l) allows to maximize the use of light by the cells. The developed model is a powerful tool for the optimal design and management of microalgae-based processes, especially outdoors, where the cultures are subject to daily culture condition variations.

Oxygen transfer and evolution in microalgal culture in open raceways

The mass transfer characteristics of all sections of a 100 m(2) raceway were evaluated. The efficiency of different diffusers was determined dynamically and the most effective was used for steady state system characterisation at water depth 0.2 m and velocity 0.22 m s(-1). Mass transfer coefficients at a gas flow rate of 6 m(3) h(-1) were 164.50, 63.66, 0.87 and 0.94 h(-1) for the paddlewheel, sump, straight and curved channel sections, with associated oxygen transfer rates of 106, 172, 27 and 39 g h(-1). Oxygen supersaturation during algal cultivation led to a reduction in biomass productivity, which was more severe with pure CO2 than flue gas. Simulations showed the energy required to increase mass transfer and reduce oxygen concentrations was more than compensated for by increased biomass and potential energy yields. Oxygen removal is likely to be a critical criterion, and maintenance of mass transfer by sparging may be necessary even when CO2 is not required.

The impact of the type of hospital on survival of multiple myeloma patients: the MICORE study

OBJECTIVE

To analyze the impact of the type of hospital in overall survival of multiple myeloma patients.

PATIENTS AND METHOD

A survival analysis was performed of all patients (n=431) diagnosed in 5 public hospitals (4 community hospitals and one university hospital) during the period 1993-2006.

RESULTS

Patients attended to in community hospitals differ significantly from those seen in the university hospital in the following variables: mean age (70 years [31-92] versus 67.9 (35-91), P=.038); percentage of stage iii patients (62.6% versus 69.1%, P=.033), and percentage of patients who had autologous stem cell transplant (8.2% versus 18.2%, P=.026). The variables associated with mortality in the multivariate analysis were age (P<.001), stage (iii versus i; P=.03) and renal failure (P=.04). The type of hospital did not reach statistical significance (hazard ratio of 0.72 (95% confidence interval 0.48-1.07), P=.1].

CONCLUSIONS

The type of hospital is not significantly associated with mortality in multiple myeloma patients. These data support our current model of health care, in which the community hospitals are responsible for the primary care of these patients, in a coordinated work with the university hospital.

Predisposing factors of diminished survival in simultaneous liver/kidney transplantation

Since the adoption of the Model for End-Stage Liver Disease, simultaneous liver/kidney transplants (SLKT) have substantially increased. Recently, unfavorable outcomes have been reported yet contributing factors remain unclear. We retrospectively reviewed 74 consecutive adult SLKT performed at our center from 2000 to 2010 and compared with kidney transplant alone (KTA, N = 544). In SLKT, patient and death-censored kidney graft survival rates were 64 ± 6% and 81 ± 5% at 5 years, respectively (median follow-up, 47 months). Multivariable analyses revealed three independent risk factors affecting patient survival: hepatitis C virus positive (HCV+, hazard ratio [HR] 2.9, 95% confidence interval [CI] 1.1-7.9), panel reactive antibody (PRA) > 20% (HR 2.8, 95% CI 1.1-7.2) and female donor gender (HR 2.9, 95% CI 1.1-7.9). For death-censored kidney graft survival, delayed graft function was the strongest negative predictor (HR 8.3, 95% CI 2.5-27.9), followed by HCV+ and PRA > 20%. The adjusted risk of death-censored kidney graft loss in HCV+ SLKT patients was 5.8 (95% CI 1.6-21.6) compared with HCV+ KTA (p = 0.008). Recurrent HCV within 1 year after SLKT correlated with early kidney graft failure (p = 0.004). Careful donor/recipient selection and innovative approaches for HCV+ SLKT patients are critical to further improve long-term outcomes.

Dietary intakes and food sources of phytoestrogens in the European Prospective Investigation into Cancer and Nutrition (EPIC) 24-hour dietary recall cohort

BACKGROUND/OBJECTIVES

Phytoestrogens are estradiol-like natural compounds found in plants that have been associated with protective effects against chronic diseases, including some cancers, cardiovascular diseases and osteoporosis. The purpose of this study was to estimate the dietary intake of phytoestrogens, identify their food sources and their association with lifestyle factors in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

SUBJECTS/METHODS

Single 24-hour dietary recalls were collected from 36,037 individuals from 10 European countries, aged 35-74 years using a standardized computerized interview programe (EPIC-Soft). An ad hoc food composition database on phytoestrogens (isoflavones, lignans, coumestans, enterolignans and equol) was compiled using data from available databases, in order to obtain and describe phytoestrogen intakes and their food sources across 27 redefined EPIC centres.

RESULTS

Mean total phytoestrogen intake was the highest in the UK health-conscious group (24.9 mg/day in men and 21.1 mg/day in women) whereas lowest in Greece (1.3 mg/day) in men and Spain-Granada (1.0 mg/day) in women. Northern European countries had higher intakes than southern countries. The main phytoestrogen contributors were isoflavones in both UK centres and lignans in the other EPIC cohorts. Age, body mass index, educational level, smoking status and physical activity were related to increased intakes of lignans, enterolignans and equol, but not to total phytoestrogen, isoflavone or coumestan intakes. In the UK cohorts, the major food sources of phytoestrogens were soy products. In the other EPIC cohorts the dietary sources were more distributed, among fruits, vegetables, soy products, cereal products, non-alcoholic and alcoholic beverages.

CONCLUSIONS

There was a high variability in the dietary intake of total and phytoestrogen subclasses and their food sources across European regions.

[Surgical wound infections in newborns: analysis of risk factors]

The incidence of surgical wound infections in neonates is high and it has an associated morbidity which extends hospital stay and gets a worse prognosis. The purpose of this study is to analyze the risk factors associated with the development of surgical wound infection and to identify susceptible patients with modifiable factors.

MATERIAL AND METHODS

Case-control study of 90 surgical procedures underwent in newborns. We analyze pre-, intra- and postoperative risk factors.

MAIN RESULTS

There are statically significant differences in terms of wound infection in dirty and contaminated surgery, reoperation, lavage of abdominal cavity, preoperative hospital stay longer than 8 days and wound closure with reabsorbable material. Furthermore, the surgical site infection is more likely in preterms patients, with a previous positive culture infection and the use of invasive devices as mechanical ventilation or central venous access. We found no relationship between wound infection and surgical time, bleeding during surgery and preoperative skin preparation with antiseptics.

CONCLUSIONS

Reoperative patients, in which dirty and contaminated surgery is performed, absorbable material for skin is used and who have a preoperative hospital stay longer than 8 days, are in risk of developping wound infection and they will require an aggressive antibiotic treatment and special postsurgical care.

[Postoperative anal prolapse in patients with anorectal malformations: 16 years of experience]

INTRODUCTION

Anal prolapse is a common postoperative complication related to anorectal malformations (MAR) surgery, which is sometimes considered to be insignificant and/or not worthy of further intervention. We analysed the causes of this complication and our current surgical protocols.

MATERIAL AND METHODS

Since 1995, 26 patients with anal prolapse have been operated secondary to surgical correction of an anorectal pathology. The most common MAR in girls (12) was cloaca (10), and in boys (14) was anorectal atresia with prostate fistula (8). The symptoms were anal pain and bleeding associated with alterations in bowel control alterations. The diagnosis in most patients was made in the first months after surgery, during the period of anal dilatations period. The surgical procedure involves prolapse resection of the prolapse and a new anoplasty. In 18 patients (69%) the prolapse was corrected before the colostomy closure on an outpatient basis. The other 8 patients (31%) underwent prolapse surgery after colostomy closure, requiring hospitalisation.

RESULTS

There were no immediate postoperative complications, improving continence and aesthetic anus appearance. In 4 patients the prolapse recurred, requiring further surgical correction.

CONCLUSIONS

Anal prolapse is a possible minor complication after anorectal correction. MAR type, the quality of the perineal musculature and defects in surgical technique are the main factors determining ia prolapse will appearance. The anal prolapse surgery indication has been recently increased (including small unilateral prolapses) as long as they are done before the colostomy closure, due to good aesthetic and functional results, requiring only outpatient surgery.

Compliance with dietary and nutrient recommendations in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Granada cohort at recruitment

BACKGROUND

The overall intake of energy and nutrients in the Granada EPIC-cohort (European Prospective Investigation into Cancer and Nutrition) is examined in order to assess compliance with the Spanish Nutritional Objectives (NO) and the Recommended Intakes (RI).

METHODS

During recruitment (1992-1996), 7,789 participants, aged 35-69, were asked about diet through a validated diet history questionnaire. Nutrient intake is compared to the NO and RI that were valid at that time. Risk of inadequate intake is estimated as the percentage of the sample with intakes: ≤ 1/3 RI (high risk), ≤ 2/3 RI- > 1/3 RI (moderate risk), ≤ RI- > 2/3 RI, > RI. Differences in intakes have been analyzed by sex and age, and by smoking status and BMI.

RESULTS

The daily intake of nutrients did not meet the NO as the total contribution of energy from proteins and fats exceeded these guidelines. Whilst intake of most nutrients was above the RI, the amount of iron, magnesium and vitamins D and E provided by the diet was not enough to meet the RI: in women aged 20-49 years, about 55% were at moderate risk for iron inadequacy, and a 20% of women for magnesium. Both sexes were at high risk of inadequacy for vitamin D, although sunlight exposure may supply adequate amounts. Never smokers showed a higher compliance to the NO.

CONCLUSION

At recruitment, the nutrient profile of the diet was unbalanced. The observed nutrient inadequacy for iron, magnesium and vitamin E might be attributed to inappropriate dietary habits, and may have implications for future disease risk.

Immunization of adult dairy cattle with a new heat-killed vaccine is associated with longer productive life prior to cows being sent to slaughter with suspected paratuberculosis

The objective of this study was to evaluate the efficacy of a new heat-killed Mycobacterium avium ssp. paratuberculosis (MAP) vaccine for control of premature culling in tuberculosis-free dairy cattle. Feces and gastrointestinal tissues were collected from 50 vaccinated cows and 38 nonvaccinated cows at slaughter and analyzed by bacteriological culture and histopathology. Vaccination was associated with a significant reduction of the frequency of vaccinated animals with MAP in feces and gut tissues compared with the nonvaccinated animals. In addition, the frequency of vaccinated animals with heavy bacterial load in gut tissues was 40% lower than the frequency of the nonvaccinated animals with the same MAP load. The peak age of paratuberculosis-associated culling was from 4.5 to 5 yr old (21%) in the vaccinated animals and from 3 to 4.5 yr old (60%) in the nonvaccinated animals. The vaccinated and nonvaccinated animals with suspected paratuberculosis were culled at an average age of 4.7 and 3.7 yr old, respectively. Therefore, a significant increase in the productive life of the vaccinated animals sent to slaughter with suspected paratuberculosis was observed. In addition, our analysis revealed a positive effect of the vaccine on the carcass weights of the animals with severe histopathological lesions at slaughter compared with the nonvaccinated animals. In summary, our findings suggest a therapeutic effect of the vaccine and a significant attenuation of pre-existing infection in cows naturally infected with paratuberculosis that were adults at the time of vaccination.

Major dietary patterns and risk of coronary heart disease in middle-aged persons from a Mediterranean country: the EPIC-Spain cohort study

BACKGROUND AND AIM

No previous study has assessed the association between major dietary patterns and the risk of coronary heart disease (CHD) in a large cohort from a Mediterranean country.

METHODS AND RESULTS

We studied prospectively 40,757 persons, aged 29-69 years, participating in the Spanish cohort of the EPIC study. Food consumption was collected between 1992 and 1996 with a validated history method. Individuals were followed-up until 2004 through record linkage with hospital discharge registers, population-based registers of myocardial infarction, and mortality registers to ascertain CHD events (fatal and non-fatal acute myocardial infarction or angina requiring revascularization). Two major dietary patterns were identified from factor analysis. The first pattern was labeled as Westernized, because of the frequent consumption of refined cereals and red meat; the second was called the evolved Mediterranean pattern, because of the frequent intake of plant-based foods and olive oil. During a median follow-up of 11 years, 606 CHD events were ascertained. No association was found between the Westernized pattern and CHD risk. In contrast, the score for the evolved Mediterranean pattern was inversely associated with CHD risk (p for trend = 0.0013); when compared with the lowest quintile of the evolved Mediterranean pattern score, the multivariable hazard ratios for CHD were 0.77 (95% confidence interval 0.61-0.98) for the second quintile, 0.64 (95% CI 0.50-0.83) for the third quintile, 0.56 (95% CI 0.43-0.73) for the fourth quintile, and 0.73 (95% CI 0.57-0.94) for the fifth quintile.

CONCLUSION

A Mediterranean diet, as consumed in this study population, was associated with a lower risk of CHD.

Production cost of a real microalgae production plant and strategies to reduce it

The cost analysis of a real facility for the production of high value microalgae biomass is presented. The facility is based on ten 3 m3 tubular photobioreactors operated in continuous mode for 2 years, data of Scenedesmus almeriensis productivity but also of nutrients and power consumption from this facility being used. The yield of the facility was close to maximum expected for the location of Almería, the annual production capacity being 3.8 t/year (90 t/ha·year) and the photosynthetic efficiency being 3.6%. The production cost was 69 €/kg. Economic analysis shows that labor and depreciation are the major factors contributing to this cost. Simplification of the technology and scale-up to a production capacity of 200 t/year allows to reduce the production cost up to 12.6 €/kg. Moreover, to reduce the microalgae production cost to approaches the energy or commodities markets it is necessary to reduce the photobioreactor cost (by simplifying its design or materials used), use waste water and flue gases, and reduce the power consumption and labor required for the production step. It can be concluded that although it has been reported that production of biofuels from microalgae is relatively close to being economically feasible, data here reported demonstrated that to achieve it by using the current production technologies, it is necessary to substantially reduce their costs and to operate them near their optimum values.

Atrial fibrillation and the pharmacological treatment: the role of propafenone

BACKGROUND

Atrial fibrillation is the most frequent cardiac rhythm disturbance, with prevalence increasing with age. This disease is a major risk factor for ischaemic stroke. The costs resulting from atrial fibrillation are really impressive. Pharmacological agents are the first line therapy for the management of atrial fibrillation. Antiarrhythmic drugs are used to terminate arrhythmias, as acute treatment for conversion of recent onset atrial fibrillation, and to maintain sinus rhythm, as chronic therapy for prevention of atrial fibrillation recurrences. Among antiarrhythmic agents, drugs that inhibit early sodium current (as propafenone) are proven effective in atrial fibrillation. In this review, the most relevant data on propafenone are provided.

DISCUSSION

The development of a sustained-release formulation of propafenone allowed to reduce the wide fluctuations in plasma levels observed with the immediate release preparation, improving compliance and adherence to therapy, by simplifying the dosing regimen from 3 to 2 daily doses. Propafenone resulted an effective measure as acute treatment for conversion of recent onset atrial fibrillation, and to maintain sinus rhythm, as chronic therapy for prevention of atrial fibrillation recurrences. In several clinical studies, strong increases of arrhythmia-free periods as well as marked increases in time to recurrence of symptomatic atrial fibrillation, such as paroxysmal supraventricular tachycardia and paroxysmal atrial fibrillation were observed. In particular, well-designed clinical studies demonstrated in large patient populations the efficacy of propafenone at several doses. At the suggested doses propafenone is usually well tolerated.

CONCLUSION

The risk of increased occurrence of regular supraventricular arrhythmia or paroxysmal supraventricular tachycardia has been overestimated for propafenone, because this adverse event was seen in all treatment groups, including placebo, with the same (and low) frequency.

Effects of long distance transportation and CO2 stunning on critical blood values in pigs

The aim of the study was to evaluate the effect of two stressful stimuli, long transportation and 80% CO(2) stunning on metabolic-physiological variables, hemodynamic and gas exchange in slaughter pigs imported from the U.S. to Mexico City with a journey time of 27 h, with 8 h of lairage at the abattoir. A total of 589 pigs from three genders were monitored. Overall results show that both stimuli caused metabolic and physiological disturbance. Gilts were more efficient in controlling glycemia after a long transport journey (24h), than castrated males (P<0.05), whose glucose was increased above the 30 mg/dL basal level. Females on arrival had 23mg/dL more lactate compared to basal levels (P<0.05). Stunning caused more physiological effects compared to transportation. Regarding the gender factor, females and entire males were more susceptible to transport stress and stunning compared to the castrated pigs, and entire males showed more complications restoring the gas exchange compared to females and barrows.

Genetic variation of toll-like receptor genes and infection by Mycobacterium avium ssp. paratuberculosis in Holstein-Friesian cattle

Toll-like receptors (TLR) are membrane proteins that play a key role in innate immunity, by recognizing pathogens and subsequently activating appropriate responses. Mutations in TLR genes are associated with susceptibility to inflammatory and infectious diseases in humans. In cattle, 3 members of the TLR family, TLR1, TLR2, and TLR4, are associated with Mycobacterium avium ssp. paratuberculosis infection, although the extent of this association for the TLR1 and TLR4 receptors has not yet been determined. Moreover, the causal variant in the TLR2 gene has not yet been unequivocally established. In this study, 24 single nucleotide polymorphisms (SNP) in the bovine TLR1, TLR2, and TLR4 genes were selected from the literature, databases, and in silico searches, for a population-based genetic association study of a Spanish Holstein-Friesian sample. Whereas previous results regarding the TLR1 gene were not corroborated, a risk haplotype was detected in TLR2; however, its low frequency indicates that this detected association should be interpreted with caution. In the case of the TLR4 gene, 3 tightly linked SNP were found to be associated with susceptibility to M. avium ssp. paratuberculosis infection. Moreover, one of these SNP, the SNP c.-226G>C, which is localized in the 5'UTR region of the TLR4 gene, has been reported to be able to alter TLR4 expression, raising the possibility that this mutation may contribute to the response of the individual to infection.

[Subcutaneously inserted central intravascular devices in the pediatric oncology patient: can we minimize their infection]

Long-term indwelling central venous access devices are frequently used in pediatric patients. Their main complication is infection, that can even mean their removal. We try to identify the risk factors really involved in this complication and in their removal. We have made a retrospective review of 120 oncologic pediatric patients who received a central venous device between 2003 and 2009. We searched for epidemiologic, clinic, microbiologic and surgical risk factors. We made a comparative data analysis among: GROUP A, children who suffered device infection, GROUP B the others. Group A was divided into early infection (first month after implantation)/late infection, removed/not removed. Data were analized with statistical program SPSS. 29 suffered from leukemia, 19 from lymphoma and the main part, 72, from solid tumour. 31% experienced infection (GROUP A), being early in the 36% of them. 16% had to be withdrawn. Data analysis revealed statistical association with the age (p=0.015) and with the reception of chemiotherapic treatment the week before the surgical insertion. The rest of the studied factors did not revealed a real association, but could be guess a relationship among infection and leukemia, subclavian catheters, those patients whose deviced was introduced using a guide over a previous catheter and also transplanted. Related to early infection the only associateon founded was with the subclavian access (p=0.018). In conclusion, in our serie long-term central venous access infection was more frequent in the younger patients and also in those who had received chemotherapy the week before the catheter implantation. The tendency towards infection in leukemia, transplanted and subclavian carriers has to be studied in a prospective way with a larger number of oncologic children.