Integration of mesophilic biogas plant in the animal slaughter process under real limitations: Techno-economic evaluation of a colombian bovine slaughterhouse.

Anaerobic digestion (AD) has been a widely tested alternative for the management and valorization of wastewater from the animal slaughter process. However, the integration of AD in slaughterhouses depends on technical and economic aspects. In Colombian slaughterhouses AD integration is limited by the availability of land. In the present study, a techno-economic evaluation of the AD of offal wastewater (OWW) stream in a laboratory scale mesophilic tubular digester was carried out. The digester was operated at organic loading rates (OLR) of 0.28, 0.50, 1.0, 1.5 and 2.0 kg VS/m3 d. Boilers and a CHP (combined heat and power) system were considered for energy integration of biogas. For the economic study, the cost structure of a Colombian slaughterhouse was considered. The AD of OWW at 2.0 kg VS/m3 d OLR was unstable with risk of inhibition. Increasing the OLR from 0.28 to 1.5 kg VS/m3 d caused a reduction in the specific biogas production (SBP) from 0.474 to 0.069 m3/kg VS However, the biogas production rate (BPR) remained constant at around 0.105 m3/m3dig d for OLRs > 0.28 kg VSm3 d. Therefore, OWW anaerobic digestion in low-cost mesophilic biogas plants is technically feasible with OLRs between 0.28 and 1.5 kg VS/m3 d. The implementation of boilers is economically favorable for OLR ≥ 1.0 kg VS/m3 d. Nevertheless, feasibility is very sensitive to variations in the cost structure. The implementation of CHP was feasible in the range of OLRs evaluated and its viability is not affected by changes in assumed costs.

Impact of data averaging strategies on V̇O2max assessment: Mathematical modeling and reliability.

BACKGROUND: No consensus exists on how to average data to optimize V ˙ O2max assessment. Although the V ˙ O2max value is reduced with larger averaging blocks, no mathematical procedure is available to account for the effect of the length of the averaging block on V ˙ O2max. AIMS: To determine the effect that the number of breaths or seconds included in the averaging block has on the V ˙ O2max value and its reproducibility and to develop correction equations to standardize V ˙ O2max values obtained with different averaging strategies. METHODS: Eighty-four subjects performed duplicate incremental tests to exhaustion (IE) in the cycle ergometer and/or treadmill using two metabolic carts (Vyntus and Vmax N29). Rolling breath averages and fixed time averages were calculated from breath-by-breath data from 6 to 60 breaths or seconds. RESULTS: V ˙ O2max decayed from 6 to 60 breath averages by 10% in low fit ( V ˙ O2max  < 40 mL kg-1  min-1 ) and 6.7% in trained subjects. The V ˙ O2max averaged from a similar number of breaths or seconds was highly concordant (CCC > 0.97). There was a linear-log relationship between the number of breaths or seconds in the averaging block and V ˙ O2max (R2  > 0.99, P < 0.001), and specific equations were developed to standardize V ˙ O2max values to a fixed number of breaths or seconds. Reproducibility was higher in trained than low-fit subjects and not influenced by the averaging strategy, exercise mode, maximal respiratory rate, or IE protocol. CONCLUSIONS: The V ˙ O2max decreases following a linear-log function with the number of breaths or seconds included in the averaging block and can be corrected with specific equations as those developed here.

Exercise Preserves Lean Mass and Performance during Severe Energy Deficit: The Role of Exercise Volume and Dietary Protein Content.

The loss of fat-free mass (FFM) caused by very-low-calorie diets (VLCD) can be attenuated by exercise. The aim of this study was to determine the role played by exercise and dietary protein content in preserving the lean mass and performance of exercised and non-exercised muscles, during a short period of extreme energy deficit (~23 MJ deficit/day). Fifteen overweight men underwent three consecutive experimental phases: baseline assessment (PRE), followed by 4 days of caloric restriction and exercise (CRE) and then 3 days on a control diet combined with reduced exercise (CD). During CRE, the participants ingested a VLCD and performed 45 min of one-arm cranking followed by 8 h walking each day. The VLCD consisted of 0.8 g/kg body weight/day of either whey protein (PRO, n = 8) or sucrose (SU, n = 7). FFM was reduced after CRE (P < 0.001), with the legs and the exercised arm losing proportionally less FFM than the control arm [57% (P < 0.05) and 29% (P = 0.05), respectively]. Performance during leg pedaling, as reflected by the peak oxygen uptake and power output (Wpeak), was reduced after CRE by 15 and 12%, respectively (P < 0.05), and recovered only partially after CD. The deterioration of cycling performance was more pronounced in the whey protein than sucrose group (P < 0.05). Wpeak during arm cranking was unchanged in the control arm, but improved in the contralateral arm by arm cranking. There was a linear relationship between the reduction in whole-body FFM between PRE and CRE and the changes in the cortisol/free testosterone ratio (C/FT), serum isoleucine, leucine, tryptophan, valine, BCAA, and EAA (r = -0.54 to -0.71, respectively, P < 0.05). C/FT tended to be higher in the PRO than the SU group following CRE (P = 0.06). In conclusion, concomitant low-intensity exercise such as walking or arm cranking even during an extreme energy deficit results in remarkable preservation of lean mass. The intake of proteins alone may be associated with greater cortisol/free testosterone ratio and is not better than the ingestion of only carbohydrates for preserving FFM and muscle performance in interventions of short duration.

Severe energy deficit upregulates leptin receptors, leptin signaling, and PTP1B in human skeletal muscle.

In obesity, leptin receptors (OBR) and leptin signaling in skeletal muscle are downregulated. To determine whether OBR and leptin signaling are upregulated with a severe energy deficit, 15 overweight men were assessed before the intervention (PRE), after 4 days of caloric restriction (3.2 kcal·kg body wt-1·day-1) in combination with prolonged exercise (CRE; 8 h walking + 45 min single-arm cranking/day) to induce an energy deficit of ~5,500 kcal/day, and following 3 days of control diet (isoenergetic) and reduced exercise (CD). During CRE, the diet consisted solely of whey protein (n = 8) or sucrose (n = 7; 0.8 g·kg body wt-1·day-1). Muscle biopsies were obtained from the exercised and the nonexercised deltoid muscles and from the vastus lateralis. From PRE to CRE, serum glucose, insulin, and leptin were reduced. OBR expression was augmented in all examined muscles associated with increased maximal fat oxidation. Compared with PRE, after CD, phospho-Tyr1141OBR, phospho-Tyr985OBR, JAK2, and phospho-Tyr1007/1008JAK2 protein expression were increased in all muscles, whereas STAT3 and phospho-Tyr705STAT3 were increased only in the arms. The expression of protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle was increased by 18 and 45% after CRE and CD, respectively (P < 0.05). Suppressor of cytokine signaling 3 (SOCS3) tended to increase in the legs and decrease in the arm muscles (ANOVA interaction: P < 0.05). Myosin heavy chain I isoform was associated with OBR protein expression (r = -0.75), phospho-Tyr985OBR (r = 0.88), and phospho-Tyr705STAT3/STAT3 (r = 0.74). In summary, despite increased PTP1B expression, skeletal muscle OBR and signaling are upregulated by a severe energy deficit with greater response in the arm than in the legs likely due to SOCS3 upregulation in the leg muscles.NEW & NOTEWORTHY This study shows that the skeletal muscle leptin receptors and their corresponding signaling cascade are upregulated in response to a severe energy deficit, contributing to increase maximal fat oxidation. The responses are more prominent in the arm muscles than in the legs but partly blunted by whey protein ingestion and high volume of exercise. This occurs despite an increase of protein tyrosine phosphatase 1B protein expression, a known inhibitor of insulin and leptin signaling.

Expanding the Donor Pool Through Intensive Care to Facilitate Organ Donation: Results of a Spanish Multicenter Study.

BACKGROUND: Intensive Care to facilitate Organ Donation (ICOD) may help to increase the donor pool. We describe the Spanish experience with ICOD. METHODS: Achieving Comprehensive Coordination in Organ Donation (ACCORD)-Spain consisted of an audit of the donation pathway from patients who died as a result of a devastating brain injury (possible donors) in 68 hospitals during November 1, 2014, to April 30, 2015. We focused on possible donors whose families were interviewed to discuss organ donation once intensive care with a therapeutic purpose was deemed futile and brain death (BD) was a likely outcome. RESULTS: Of the 1970 possible donors in ACCORD-Spain, in 257, the family was interviewed once the decision had been made not to intubate/ventilate (n = 105), with the patient under intubation/ventilation outside of the intensive care unit (n = 59), or with the patient intubated/ventilated within the intensive care unit (n = 93).Consent to ICOD was obtained in 174 cases. Consent was higher when the donor coordinator participated in the interview (odds ratio, 2.32; 95% confidence interval, 1.33-4.11; P = 0.003). One hundred thirty-one patients developed BD, of whom 117 transitioned to actual donation after BD. Of the 35 patients who did not develop BD, 2 transitioned to actual donation after circulatory death. Sixteen patients subject to ICOD were finally medically unsuitable organ donors.ICOD contributed to 24% of the 491 actual donors registered in ACCORD-Spain. CONCLUSIONS: Despite the complexity of the interview, the majority of families consented to ICOD. Estimating the probability of BD and assessing medical suitability are additional challenges of the practice. ICOD represents a clear opportunity to increase the donor pool and ensures organ donation is posed at every end-of-life care pathway.

Limitations to oxygen transport and utilization during sprint exercise in humans: evidence for a functional reserve in muscle O2 diffusing capacity.

To determine the contribution of convective and diffusive limitations to V̇(O2peak) during exercise in humans, oxygen transport and haemodynamics were measured in 11 men (22 ± 2 years) during incremental (IE) and 30 s all-out cycling sprints (Wingate test, WgT), in normoxia (Nx, P(IO2): 143 mmHg) and hypoxia (Hyp, P(IO2): 73 mmHg). Carboxyhaemoglobin (COHb) was increased to 6-7% before both WgTs to left-shift the oxyhaemoglobin dissociation curve. Leg V̇(O2) was measured by the Fick method and leg blood flow (BF) with thermodilution, and muscle O2 diffusing capacity (D(MO2)) was calculated. In the WgT mean power output, leg BF, leg O2 delivery and leg V̇(O2) were 7, 5, 28 and 23% lower in Hyp than Nx (P < 0.05); however, peak WgT D(MO2) was higher in Hyp (51.5 ± 9.7) than Nx (20.5 ± 3.0 ml min(-1) mmHg(-1), P < 0.05). Despite a similar P(aO2) (33.3 ± 2.4 and 34.1 ± 3.3 mmHg), mean capillary P(O2) (16.7 ± 1.2 and 17.1 ± 1.6 mmHg), and peak perfusion during IE and WgT in Hyp, D(MO2) and leg V̇(O2) were 12 and 14% higher, respectively, during WgT than IE in Hyp (both P < 0.05). D(MO2) was insensitive to COHb (COHb: 0.7 vs. 7%, in IE Hyp and WgT Hyp). At exhaustion, the Y equilibration index was well above 1.0 in both conditions, reflecting greater convective than diffusive limitation to the O2 transfer in both Nx and Hyp. In conclusion, muscle V̇(O2) during sprint exercise is not limited by O2 delivery, O2 offloading from haemoglobin or structure-dependent diffusion constraints in the skeletal muscle. These findings reveal a remarkable functional reserve in muscle O2 diffusing capacity.

Muscle activation during exercise in severe acute hypoxia: role of absolute and relative intensity.

The aim of this study was to determine the influence of severe acute hypoxia on muscle activation during whole body dynamic exercise. Eleven young men performed four incremental cycle ergometer tests to exhaustion breathing normoxic (FIO2=0.21, two tests) or hypoxic gas (FIO2=0.108, two tests). Surface electromyography (EMG) activities of rectus femoris (RF), vastus medialis (VL), vastus lateralis (VL), and biceps femoris (BF) were recorded. The two normoxic and the two hypoxic tests were averaged to reduce EMG variability. Peak VO2 was 34% lower in hypoxia than in normoxia (p<0.05). The EMG root mean square (RMS) increased with exercise intensity in all muscles (p<0.05), with greater effect in hypoxia than in normoxia in the RF and VM (p<0.05), and a similar trend in VL (p=0.10). At the same relative intensity, the RMS was greater in normoxia than in hypoxia in RF, VL, and BF (p<0.05), with a similar trend in VM (p=0.08). Median frequency increased with exercise intensity (p<0.05), and was higher in hypoxia than in normoxia in VL (p<0.05). Muscle contraction burst duration increased with exercise intensity in VM and VL (p<0.05), without clear effects of FIO2. No significant FIO2 effects on frequency domain indices were observed when compared at the same relative intensity. In conclusion, muscle activation during whole body exercise increases almost linearly with exercise intensity, following a muscle-specific pattern, which is adjusted depending on the FIO2 and the relative intensity of exercise. Both VL and VM are increasingly involved in power output generation with the increase of intensity and the reduction in FIO2.

Thermic model to predict biogas production in unheated fixed-dome digesters buried in the ground.

In many developing countries, simple biogas digesters are used to produce energy for domestic purposes from anaerobic digestion of animal manure. We developed a simple, one-dimensional (1-D), thermal model with easily available input data for unheated, unstirred, uninsulated, fixed-dome digesters buried in the soil to study heat transfer between biogas digester and its surroundings. The predicted temperatures in the dome, biogas, and slurry inside the digester and the resulting biogas production are presented and validated. The model was well able to estimate digester temperature (linear slope nearly 1, R(2) = 0.96). Model validation for methane production gave root-mean-square error (RMSE) of 54.4 L CH4 digester(-1) day(-1) and relative-root-mean-square errors (rRMSEP(%)) of 35.4%. The validation result was considerably improved if only using winter data (RMSE = 26.1 L CH4 digester(-1) day(-1); rRMSEP(%) = 17.7%). The model performed satisfactorily in light of the uncertainties attached to it. Since unheated digesters suffer critically low methane production during the winter, the model could be particularly useful for assessing methane production and for improving the ability of unheated digesters to provide sufficient energy during cold periods.

Towards thermal design optimization of tubular digesters in cold climates: a heat transfer model.

A cold climate, low cost, tubular digester is monitored and temperatures from different parts of the slurry, greenhouse, and adobe walls are presented, discussing the thermal performance of the digester. The slurry exhibits a vertical gradient of 6°C, with a mean value of 24.5°C, while the ambient temperature varies from 10°C to 30°C, showing the efficiency of the system as a solar heat collector with thermal inertia. A simple time-dependent thermal model is developed using inputs of solar radiation, wind velocity, ambient temperature, and digester geometry. The model outputs include temperatures of the slurry, the biogas, its holding membrane and the greenhouse air, wall and cover. Radiative, convective and conductive heat transfer phenomena are considered between all system elements. The model has 0.47°C (2%) standard error for the average slurry temperature. This model can be used to predict the influence of geometry and materials on the performance of the digester.

Left ventricular ballooning syndrome due to vasospasm of the middle portion of the left anterior descending coronary artery.

We report a case that shows vasospasm to be one of the mechanisms responsible for left ventricular ballooning syndrome. Our case suggests that identical ventriculographic findings in patients with tako-tsubo syndrome and those with coronary vasospasm of a long left anterior descending artery coronary artery may be due to a common etiology.

Supervivencia a medio plazo de los pacientes operados en cirugía cardiaca mayor / Mid-term survival of patients undergoing major cardiac surgery

Introducción y objetivos. La supervivencia en cirugía cardiaca es un parámetro de calidad de la cirugía realizada. Este estudio analiza la supervivencia y los factores de riesgo asociados con la mortalidad a medio plazo en la cirugía cardiaca del Hospital Universitario Son Dureta. Métodos. Desde noviembre de 2002 hasta diciembre de 2007, se intervino a 1.938 pacientes, que fueron estratificados en cuatro grupos de edad. De los 1.900 dados de alta vivos, se pudo realizar el seguimiento de 1.844 (fecha de corte, 31 de diciembre de 2008). La supervivencia se estimó mediante curvas de Kaplan-Meier y las variables asociadas con la mortalidad a medio plazo, mediante un análisis de regresión de Cox. Resultados. La mortalidad hospitalaria de los 1.938 pacientes fue del 1,96% (intervalo de confianza [IC] del 95%, 1,36-2,6%). La supervivencia acumulada a 1, 3 y 5 años fue del 98, el 94 y el 90%, respectivamente. La media del tiempo de seguimiento fue de 3,2 (0,01-6,06) años. La supervivencia de los pacientes de 70 años o más fue menor que la de los menores de dicha edad (log rank test, < 0,0001). La mortalidad observada al final del seguimiento fue del 6,5% (IC del 95%, 5,4-7,7%) y se asoció de forma independiente con la edad ≥ 70 años, el antecedente de función ventricular muy deprimida (fracción de eyección < 30%), hipertensión pulmonar severa, diabetes mellitus, anemia preoperatoria, accidente cerebrovascular postoperatorio y estancia hospitalaria. Conclusiones. Los pacientes dados de alta vivos presentaron una supervivencia excelente a medio plazo. La tasa de mortalidad varió en función de la edad y de otros factores presentes antes y después de la cirugía cardiaca (AU)

Introduction and Objectives. Evaluating patient outcomes following cardiac surgery is a means of measuring the quality of that surgery. The present study analyzes survival and the risk factors associated with mid-term mortality of patients undergoing cardiac surgery in Son Dureta University Hospital (Palma, Balearic Islands, Spain). Methods. From November 2002 thru December 2007, 1938 patients underwent interventions. Patients were stratified in 4 age groups. Of 1900 patients discharged from hospital, 1844 were followed until December 31, 2008. Following discharge, we constructed Kaplan-Meier survival curves and performed Cox regression analysis to determine which variables associated with mid-term mortality. Results. In-hospital mortality of the 1,938 patients was 1.96% (CI 95%, 1.36%-2.6%). Survival probability at 1, 3 and 5years follow-up was 98%, 94% and 90%, respectively. Mean follow-up was 3.2 (0.01-6.06) years. Patients aged ≥70years showed a lower survival rate than those aged <70 log="" rank="" test="" i=""> P<.0001). At the end of follow-up, mortality was 6.5% (CI 95%, 5.4%-7.7%). Age ≥70years, a history of severe ventricular dysfunction (ejection fraction<30 severe="" pulmonary="" hypertension="" diabetes="" mellitus="" preoperative="" anemia="" postoperative="" stroke="" and="" hospital="" stay="" were="" independently="" associated="" with="" mid-term="" mortality="">. Conclusions. Mid-term survival after discharge was highly satisfactory. Mid-term mortality varied with age and other pre- and postoperative factors (AU)

[Mid-term survival of patients undergoing major cardiac surgery]. / Supervivencia a medio plazo de los pacientes operados en cirugía cardiaca mayor.

INTRODUCTION AND OBJECTIVES: Evaluating patient outcomes following cardiac surgery is a means of measuring the quality of that surgery. The present study analyzes survival and the risk factors associated with mid-term mortality of patients undergoing cardiac surgery in Son Dureta University Hospital (Palma, Balearic Islands, Spain). METHODS: From November 2002 thru December 2007, 1938 patients underwent interventions. Patients were stratified in 4 age groups. Of 1900 patients discharged from hospital, 1844 were followed until December 31, 2008. Following discharge, we constructed Kaplan-Meier survival curves and performed Cox regression analysis to determine which variables associated with mid-term mortality. RESULTS: In-hospital mortality of the 1,938 patients was 1.96% (CI 95%, 1.36%-2.6%). Survival probability at 1, 3 and 5 years follow-up was 98%, 94% and 90%, respectively. Mean follow-up was 3.2 (0.01-6.06) years. Patients aged ≥ 70 years showed a lower survival rate than those aged <70 (log rank test, P <.0001). At the end of follow-up, mortality was 6.5% (CI 95%, 5.4%-7.7%). Age ≥ 70 years, a history of severe ventricular dysfunction (ejection fraction < 30%), severe pulmonary hypertension, diabetes mellitus, preoperative anemia, postoperative stroke, and hospital stay were independently associated with mid-term mortality. CONCLUSIONS: Mid-term survival after discharge was highly satisfactory. Mid-term mortality varied with age and other pre- and postoperative factors.

Neumonía nosocomial por Staphylococcus aureus resistente a meticilina de origen comunitario productor de leucocidina de Panton-Valentine / Nosocomial pneumonia due to community-acquired, methicillin-resistant, Panton-Valentine leukocidinproducing Staphylococcus aureus

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Effect of preoperative mild renal dysfunction on mortality and morbidity following valve cardiac surgery.

The objective of this study was to investigate the effect of preoperative mild renal dysfunction (RD) not requiring dialysis on mortality and morbidity after valve cardiac surgery (VCS). We studied 681 consecutive patients (2002-2006) who underwent valve cardiac surgery with or without coronary artery bypass graft (CABG). Preoperative RD was calculated with the abbreviated Modification of Diet in Renal Disease formula and was defined as a glomerular filtration rate <60 ml/min/1.73 m(2). Logistic regression analysis was used to assess the effect of preoperative renal dysfunction on operative and adverse outcomes. Two hundred and seven patients (30%) had preoperative mild RD. Patients with preoperative RD were older, had a higher rate of preoperative anaemia (43% vs. 25%, P<0.001) and more comorbidities. Patients with preoperative RD had worse outcomes with more reoperation (6.8% vs. 2.3%, P<0.001). Preoperative RD was significantly and independently associated with more red blood cell transfusions and longer hospital stay (median 9 vs. 8 days, P<0.001). Mortality was similar in both groups (3.4% vs. 2.3%, P=0.43). Preoperative mild renal dysfunction in patients undergoing cardiac valve surgery is an independent marker of postoperative morbidity.