Increased Carbon Dioxide Production Research Articles

Experimental investigating of the effect of CO2 injection parameters on asphaltene precipitation and formation damage in live oil

AbstractWith the increasing consumption of oil in the world and increasing production of oil from oil reservoirs, the reservoir pressure starts to decrease. On the other side, the use of oil leads to an increase in carbon dioxide production in the environment and causes global warming.One of the effective methods of reducing the amount of carbon dioxide emitted into the atmosphere and increasing the reservoir's pressure is CO2‐EOR and carbon capturing and storing (CCS) which injects produced carbon dioxide from industrial sources into underground reservoirs. Carbon dioxide reduces oil viscosity and increases oil mobility producing an economical state. Moreover, with CO2‐EOR and CCS carbon dioxide can be stored in a depleted reservoir and helps reduce pollution and global warming.Besides the environmental and economic benefits due to reducing carbon dioxide emissions to the atmosphere and increasing oil production, CO2 injection causes various problems in the formation. Many experiments indicate that asphaltene precipitation and wettability alteration caused by asphaltene, dissolution/precipitation of rock, salt precipitation, and sludge formation are some of the problems that occur during CO2 injection operations in low pressure and temperature. However, few experiments evaluate asphaltene precipitation effective factors, such as pressure, injection rates, temperature, etc., in high temperatures and pressure (HPHT) near reservoir conditions. Therefore, there was a need for a comprehensive investigation of various factors and the impact of each of them on the asphaltene precipitation and formation damage in HPHT conditions, so this research was designed to help future simulation and industrial utilization.A core‐flood setup was prepared to conduct CO2 flooding experiments and formation damage studies in HPHT conditions. The main objective of this study was to evaluate the effect of different parameters including pressure, injection rate, and type of injected gas on asphaltene and its effect on formation damage caused by CO2 injection. The second goal of this study was to investigate the optimum injection in every section. The third goal was to determine the oil recovery during the process of CO2 injection in different conditions.The results showed that an injection rate of 0.1 cc/min and higher injection pressures minimized asphaltene precipitation and maximized oil recovery. Replacing CO2 with natural gas liquids (NGL) gas reduced oil production and asphaltene precipitation. Overall, the experiments demonstrated the importance of optimizing injection parameters to limit formation damage during CO2 flooding. © 2024 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.

Macronutrient and Micronutrient Intake in Children with Lung Disease.

This review article aims to summarize the literature findings regarding the role of micronutrients in children with lung disease. The nutritional and respiratory statuses of critically ill children are interrelated, and malnutrition is commonly associated with respiratory failure. The most recent nutrition support guidelines for critically ill children have recommended an adequate macronutrient intake in the first week of admission due to its association with good outcomes. In children with lung disease, it is important not to exceed the proportion of carbohydrates in the diet to avoid increased carbon dioxide production and increased work of breathing, which potentially could delay the weaning of the ventilator. Indirect calorimetry can guide the process of estimating adequate caloric intake and adjusting the proportion of carbohydrates in the diet based on the results of the respiratory quotient. Micronutrients, including vitamins, trace elements, and others, have been shown to play a role in the structure and function of the immune system, antioxidant properties, and the production of antimicrobial proteins supporting the defense mechanisms against infections. Sufficient levels of micronutrients and adequate supplementation have been associated with better outcomes in children with lung diseases, including pneumonia, cystic fibrosis, asthma, bronchiolitis, and acute respiratory failure.

Influence of dietary fiber content and horn status on thermoregulatory responses of Brown Swiss dairy cows under thermoneutral and short-term heat stress conditions

In the present experiment, 10 horned and 10 disbudded mid-lactating Brown Swiss cows were included in a crossover feeding trial with a hay or hay and concentrate diet. The effects of dietary neutral detergent fiber (NDF) content and horn status on thermoregulatory responses under thermoneutral and short-term heat stress conditions were studied, as both are considered to ease the cow's thermoregulation under an environmental heat load. Cows received either ad libitum hay and alfalfa pellets (85:15, C-, NDF content: 41.0%) or restricted amounts of hay and concentrate (70:30, C+, NDF content: 34.5%). The level of restriction applied with the C+ diet was determined from pre-experimental ad libitum intakes, ensuring that both diets provided the same intake of net energy for lactation (NEL). For data collection, cows were housed in respiration chambers for 5 d. The climatic conditions were 10°C and 60% relative humidity (RH), considered thermoneutral (TN) conditions (temperature-humidity index (THI): 52) for d 1 and 2, and 25°C and 70% RH, considered heat stress (HS) conditions (THI: 74), for d 4 and 5. On d 3, the temperature and RH were increased gradually. Compared with TN, HS conditions increased the water intake, skin temperature, respiration and heart rates, and endogenous heat production. They did not affect body temperature, feed intake, or milk production. Lowering dietary fiber content via concentrate supplementation lowered methane and increased carbon dioxide production. It did not mitigate physiological responses to HS. Although the responses of horned and disbudded cows were generally similar, the slower respiration rates of horned cows under HS conditions indicate a possible, albeit minor, role of the horn in thermoregulation. In conclusion, future investigations on nutritional strategies must be conducted to mitigate mild heat stress.

Species-Dependent Metabolic Response to Lipid Mixtures in Wine Yeasts.

Lipids are essential energy storage compounds and are the core structural elements of all biological membranes. During wine alcoholic fermentation, the ability of yeasts to adjust the lipid composition of the plasma membrane partly determines their ability to cope with various fermentation-related stresses, including elevated levels of ethanol and the presence of weak acids. In addition, the lipid composition of grape juice also impacts the production of many wine-relevant aromatic compounds. Several studies have evaluated the impact of lipids and of their metabolism on fermentation performance and aroma production in the dominant wine yeast Saccharomyces cerevisiae, but limited information is available on other yeast species. Thus, the aim of this study was to evaluate the influence of specific fatty acid and sterol mixtures on various non-Saccharomyces yeast fermentation rates and the production of primary fermentation metabolites. The data show that the response to different lipid mixtures is species-dependent. For Metschnikowia pulcherrima, a slight increase in carbon dioxide production was observed in media enriched with unsaturated fatty acids whereas Kluyveromyces marxianus fermented significantly better in synthetic media containing a higher concentration of polyunsaturated fatty acids than monounsaturated fatty acids. Torulaspora delbrueckii fermentation rate increased in media supplemented with lipids present at an equimolar concentration. The data indicate that these different responses may be linked to variations in the lipid profile of these yeasts and divergent metabolic activities, in particular the regulation of acetyl-CoA metabolism. Finally, the results suggest that the yeast metabolic footprint and ultimately the wine organoleptic properties could be optimized via species-specific lipid adjustments.

Nutritional Care in Acute and Chronic Illness

Nutrition is essential for maintaining good health and preventing diseases, especially in patients suffering from acute or chronic diseases, infectious diseases, or critical illnesses because dietary intake involves both quantitative and qualitative changes and may disturb energy homeostasis (Richardson & Davidson, 2003). The metabolism of patients with critical illnesses is categorized as hypercatabolic, with significant loss of lean body tissue facilitated by the immune-neuroendocrine response of acute critical illness (Mechanick & Brett, 2005). Therefore, facing hunger during a period of physiological stress because of disease or treatment, results in an increased basal metabolic rate, accelerated protein breakdown, and increased energy and nutritional requirements in response to tissue damage, infection, and inflammation. This situation will develop rapidly into malnutrition or further exacerbate malnutrition because of inflammation and metabolic stress associated with diseases and injuries (Wortinger & Burns, 2015). The inflammatory response triggers the neurophysiology of patients and severely affects digestive behavior (Konsman & Dantzer, 2001), especially in terms of increasing demand for protein to provide amino acids for immunoglobulin and acute-phase protein production, both of which are fundamental to proper immune system functions. Under conditions of severe nutrient deficiency, the protein catabolism of the viscera and skeletal muscle for energy and protein generation will occur quickly in the acute phase. This catabolism has the potential to affect the cardiovascular, respiratory, immune, and all other body systems (Chan, 2015). Therefore, malnutrition during hospitalization may initiate immunosuppression and increase the risk of bacterial spread and sepsis, delayed wound healing, impaired organ function, prolonged hospitalization, and morbidity and mortality (Chan, 2015). As severe malnutrition is related to poor illness or treatment outcomes, which is associated with longer hospitalization and increased medical expenses, assessing patients' nutritional status and providing adequate nutritional care are critical. A nutritional assessment that includes body weight, physical condition and muscle condition, and calculation of resting energy requirements must be included as a standard part of the initial examination received by each patient. The results of this assessment should be considered together with the patient's illness status to formulate a nutritional care plan to provide the nutrition (energy, protein, essential fatty acids, and micronutrients) necessary to meet daily requirements, minimize metabolism, and break down proteins to support the immune system and wound healing (Chan, 2010). It is necessary to provide patients with full-spectrum nutrition and be aware that overeating may also cause metabolic and gastrointestinal complications, liver dysfunction, increased carbon dioxide production, and respiratory muscle weakness (Chan, 2010). Natural food should be provide the main source of nutrition as much as possible, and patients should be encouraged to eat a high-quality, complete diet. Although nutritionists may contribute to the assessment and design of nutritional plans for patients in clinical practice, their limited availability in hospitals disallows their providing the individualized attention required by each patient (Xu et al., 2017). Nurses have the most contact with patients and are most sensitive to their illness conditions. They are able to quickly assess the patient's nutritional needs according to changes in the situation, make referrals, and provide consultations on diet modifications. As the nutritional status of patients is involved in their treatment and physical recovery, nurses have always shouldered inter-professional responsibilities and played an essential role in the nutritional care of patients (Xu et al., 2017). For hospitalized patients and residents of long-term care institutions, nurses are able to pay attention to their nutritional related problems during the process of care, respond rapidly to nutrition-related treatment needs, and participate in the transdisciplinary professional team to prevent patient malnutrition.

Nutritional support for patients in the neurosurgical and neurological intensive care unit: are special guidelines necessary?

The nutritional support for patients in the intensive care unit is an integral component of intensive care. Patients of a neurological and neurosurgical profile who are in the intensive care unit are a special group of patients, whose treatment differs both in the used intensive therapy methods and nutritional support provision.
 Indirect calorimetry should be used to determine the energy requirements in neurosurgical and neurological patients. The use of calculation equations, such as the Harris-Benedict equation, is impossible due to its large discrepancy with indirect calorimetry data. The need for protein in patients of this category should be made at the rate of 1.22.0 g/kg of body weight per day. The urinary nitrogen loss data should not be used as a routine method for determining protein requirements in these patients. Insufficient energy and protein intake in neurosurgical and neurological patients can lead to increased infectious complications, mechanical ventilation duration, and length of intensive care unit stay, and rehabilitation potential deterioration. Excessive energy intake can lead to increased carbon dioxide production and intra-abdominal pressure, thereby increasing the intracranial pressure and aggravating secondary brain damage.
 The central nervous system damage leads to increased intestinal permeability, worsens motility, and even changes the microbiota, which requires constant monitoring of the gastrointestinal tract functions to provide adequate nutritional support in neurological and neurosurgical patients who are in the intensive care unit.
 In modern guidelines, both on intensive care and nutritional support, recommendations for its implementation in these patients are unclear.

Pathophysiology and Treatment of Malignant Hyperthermia

Malignant hyperthermia (MH) is caused by a genetic disorder of the skeletal muscle that induces a hypermetabolic response when patients are exposed to a triggering agent such as volatile inhaled anesthetics or depolarizing neuromuscular blockers. Symptoms of MH include increased carbon dioxide production, hyperthermia, muscle rigidity, tachypnea, tachycardia, acidosis, hyperkalemia, and rhabdomyolysis. Common scenarios for triggering agents are those used are during surgery and rapid sequence intubation. Hypermetabolic symptoms have a rapid onset; hence, prompt recognition and treatment are vital to prevent morbidity and mortality. The first-line treatment agent for an MH response is dantrolene. Further treatment includes managing complications related to a hypermetabolic response such as hyperkalemia and arrhythmias. This review is focused on the recognition and treatment considerations of MH in the emergency department to optimize therapy and improve patient morbidity and mortality.

Adipokinetic hormone promotes infection with entomopathogenic fungus Isaria fumosorosea in the cockroach Periplaneta americana

The adipokinetic hormones (AKHs) are known to be involved in insect immunity, thus their role in the cockroach Periplaneta americana infected with the entomopathogenic fungus Isaria fumosorosea was examined in this study. The application of I. fumosorosea resulted in a significant increase in both Akh gene expression and AKH peptide levels. Further, co-application of I. fumosorosea with Peram-CAH-II significantly enhanced cockroach mortality compared with the application of I. fumosorosea alone. The mechanism of AKH action could involve metabolic stimulation, which was indicated by a significant increase in carbon dioxide production; this effect can increase the turnover and thus efficacy of toxins produced by I. fumosorosea in the cockroach's body. I. fumosorosea treatment resulted in a significant decrease in haemolymph nutrients (carbohydrates and lipids), but co-application with Peram-CAH-II restored control level of lipids or even further increased the level of carbohydrates. Such nutritional abundance could enhance the growth and development of I. fumosorosea. Further, both I. fumosorosea and Peram-CAH-II probably affected oxidative stress: I. fumosorosea alone curbed the activity of catalase in the cockroach's gut, but co-application with Peram-CAH-II stimulated it. Interestingly, the hormone alone had no effect on catalase activity. Taken together, the results of the present study demonstrate the interactions between the fungus and AKH activity; understanding this relationship could provide insight into AKH action and may have practical implications for insect pest control in the future.

Life-cycle assessment of water injection into hydrocarbon reservoirs using exergy concept

Water injection into hydrocarbon reservoirs has been studied in great detail both from the subsurface and from surface perspectives, usually aiming at maximizing the production of low-cost oil. Here, the exergy concept is used to examine the potential life-cycle impact of injecting water into hydrocarbon reservoirs by considering the energy requirements of the process. It is found that the exergy recovery factor, being the ratio between the produced exergy corrected for material and process exergy requirements for its extraction and the gross exergy of the source decreases with time. Usually the process exergy requirements to produce the exergy increases with time. In the case of water injection the main contributors to the process exergy are due to treatment of water and the pumping of reservoir fluids. The method presented in this paper can also quantify the amount of CO2 per unit volume of the produced oil. It is contended that the volume of water required to produce the oil is an important indicator of the efficiency of water drive recovery of oil. Moreover, the amount of carbon dioxide produced for the extraction of one barrel of oil depends strongly on the water cut fw.in the producers. Below fw = 80% little CO2 is produced; however, when fw> 90% a small increase in the water cut leads to a large increase of carbon dioxide production. This emphasizes the importance of water management in water drive recovery of oil.

Life-threatening Episodes of Malignant Hyperthermia Following Halothane Anesthesia in Three Children: A Case Series and Review of Literature.

ABSTRACTMalignant hyperthermia (MH) is an inherited, pharmacogenetic disorder of the skeletal muscle, characterized by dangerous hypermetabolic state after anesthesia with succinylcholine and/ or volatile halogenated anesthetic agents, clinically manifested as hyperpyrexia and related complications like tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, rigid muscles, rhabdomyolysis and disseminated intravascular coagulation (DIC). Here we present a series of three cases of MH, admitted in our hospital in a span of 8 months for three different operative procedures to be done under general anesthesia (cleft lip repair, Duhamel's operation for Hirschsprung's disease and surgical repair of development dysplasia of hip), who developed probable hyperthermia owing to Halothane being used as an anesthetic agent.How to cite this articleLaha S, Giri PP, Saha A, Gupta PP, De A. Life-threatening Episodes of Malignant Hyperthermia Following Halothane Anesthesia in Three Children: A Case Series and Review of Literature. Indian Journal of Critical Care Medicine, January 2019;23(1):47-50.

Effect of Different Doses of Granisetron on Preventing Postoperative Shivering in Patients undergoing Septorhinoplasty under General Anesthesia

Background: Postoperative shivering is a frequent complication in recovery room after general anesthesia and has been reported in 40-70% of patients undergoing surgery. Postoperative shivering might cause hypoxemia, increase in oxygen consumption, a linear increase in carbon dioxide production, lactic acidosis, and increased intraocular pressure and intracranial pressure. The aim of this study was to compare the effects of different doses of granisetron on preventing postoperative shivering in patients undergoing septorhinoplasty under general anesthesia. Methods: 90 patients aged 18-60 years old with grades Ι or ΙΙ of American Society of Anesthesiologists (ASA) physicals classification were allocated to the study. The first group (G1) received Granisetron 1mg Intra Venous (IV) before anesthesia induction; the second group (G2) received 3mg Granisetron IV before anesthesia induction and the last group, the control group, received Normal Saline (NS). Three groups were matched regarding age, gender, weight and duration of surgery. Shivering grade and time of operation were recorded in the recovery room. Results: 90 patients scheduled for septorhinoplasty, including 54 men and 36 women, were enrolled to the study. The mean age of the patients was 28.53 ± 8.62 (18-60) years. The number of the patients suffering from shivering in the recovery room was significantly less in group G2 rather than control group (P=0.006) and also need to therapy was significantly less in this group (G2) compared with the control group (P=0.002). Conclusion: Prophylactic use of granisetron (3mg, IV) can be effective in preventing postoperative shivering following septorhinoplasty.

Water-assisted oxygen activation during gold-catalyzed formic acid decomposition under SCR-relevant conditions

Owing to the problems associated with the use of urea as an ammonia precursor compound in the selective catalytic reduction process in automobiles, alternative compounds such as ammonium formate, methanamide, and guanidinium formate have been suggested as more efficient and cleaner candidates. For the application of such formate-based ammonia precursors, a fundamental understanding of catalytic formic acid decomposition in the presence of the diesel exhaust components water and oxygen is required. Oxygen activation is a reaction step common to many catalytic processes. We observed that oxygen activation over titania and base-modified titania-supported gold catalysts is greatly enhanced in the presence of water, resulting in a significant increase in carbon dioxide production from the decomposition of formic acid. Unlike the supports, gold catalyzed the selective production of carbon dioxide. Monodentate and bidentate formates are the kinetically relevant surface species for carbon monoxide and carbon dioxide production, respectively. The support acts as a reservoir, storing bidentate formates that do not react in the steady state when formic acid and oxygen (and water) are co-fed. However, during transient experiments, when the feed is switched from formic acid to oxygen (and water), they are reactivated upon reverse spillover to the active site associated with gold, where they decompose to carbon dioxide. In the presence of oxygen and water, carbon monoxide oxidation and the water gas shift reaction do not produce carbon dioxide. Instead, a direct oxidative-dehydrogenation-type pathway proceeds, which strongly differs from stoichiometric formic acid decomposition. A kinetically consistent mechanism is proposed in which the hydroperoxy species facilitate the C–H bond cleavage of formates to release carbon dioxide and water in the rate-determining step.

Hypothalamic over-expression of VGF in the Siberian hamster increases energy expenditure and reduces body weight gain.

VGF (non-acronymic) was first highlighted to have a role in energy homeostasis through experiments involving dietary manipulation in mice. Fasting increased VGF mRNA in the Arc and levels were subsequently reduced upon refeeding. This anabolic role for VGF was supported by observations in a VGF null (VGF-/-) mouse and in the diet-induced and gold-thioglucose obese mice. However, this anabolic role for VGF has not been supported by a number of subsequent studies investigating the physiological effects of VGF-derived peptides. Intracerebroventricular (ICV) infusion of TLQP-21 increased resting energy expenditure and rectal temperature in mice and protected against diet-induced obesity. Similarly, ICV infusion of TLQP-21 into Siberian hamsters significantly reduced body weight, but this was due to a decrease in food intake, with no effect on energy expenditure. Subsequently NERP-2 was shown to increase food intake in rats via the orexin system, suggesting opposing roles for these VGF-derived peptides. Thus to further elucidate the role of hypothalamic VGF in the regulation of energy homeostasis we utilised a recombinant adeno-associated viral vector to over-express VGF in adult male Siberian hamsters, thus avoiding any developmental effects or associated functional compensation. Initially, hypothalamic over-expression of VGF in adult Siberian hamsters produced no effect on metabolic parameters, but by 12 weeks post-infusion hamsters had increased oxygen consumption and a tendency to increased carbon dioxide production; this attenuated body weight gain, reduced interscapular white adipose tissue and resulted in a compensatory increase in food intake. These observed changes in energy expenditure and food intake were associated with an increase in the hypothalamic contents of the VGF-derived peptides AQEE, TLQP and NERP-2. The complex phenotype of the VGF-/- mice is a likely consequence of global ablation of the gene and its derived peptides during development, as well as in the adult.

The effect of post-harvest treatment on the quality of sweet cherries during storage

Cherries are a traditional commodity grown in the Czech Republic. Placing into a cold room is essential for the fruit to be preserved in the long term. Even if optimum storage conditions are followed, the shelf life is relatively short. This study observed the effect of packing cherries into the Xtend polymer wrap on slowing down the degradation of the fruit during the storage period. The experiment was conducted using 4 varieties of the sweet cherry (Prunus avium L.) from the identical site (Stošíkovice, Czech Republic) - 'Vanda', 'Kordia', 'Sweetheart' and 'Regina'. Part of the fruit was stored at 20 °C for 7 days (conditions in retail chains) and other part of the fruit was stored at 1 °C for 50 days, first half of fruit was stored in Xtend polymer wrap and second half in the normal air conditions. Changes were also investigated in fruit quality parameters (soluble solids, titratable acidity, weight loss, peel firmness and respiration intensity) under the shelf life conditions when the fruit was placed at the distribution temperature of 20 °C after removal from the store and analysed after 5 and 10 days. Packed fruit exhibited significantly lower weight loss than unpacked fruit. Unpacked fruits showed visible signs of wilting and it is connected to the water loss and loss of turgidity of fruit. Soluble solids content and titratable acidity reduced generally less in unpacked fruit, which was probably related to the higher weight loss in this variant. Between the packaged and control fruit firmness was not statistically significant. Carbon dioxide production characteristic the intensity of respiration was typically higher at 1 °C for fruit packed in the Xtend film. This fruit, however, largely responded by reducing the intensity of respiration when removed from the store and placed at 20 °C, whereas in unpacked fruit there was a several-fold increase in carbon dioxide production under such conditions.

Comparison of Clonidine, Dexmedetomidine and Tramadol for Control of Post Spinal Shivering: A Randomized Double Blind Clinical Study

Comparison of Clonidine, Dexmedetomidine and Tramadol for Control of Post Spinal Shivering: A Randomized Double Blind Clinical Study

Neurophysiological Evidence for a Cortical Contribution to the Wakefulness-Related Drive to Breathe Explaining Hypocapnia-Resistant Ventilation in Humans.

Human ventilatory activity persists, during wakefulness, even when hypocapnia makes it unnecessary. This peculiarity of human breathing control is important to speech and speech-breathing insofar as speech induces hypocapnia. This study evidences a specific respiratory-related cortical activity. This suggests that human hypocapnic breathing is driven, at least in part, by cortical mechanisms similar to those involved in volitional breathing, in breathing against mechanical constraints or with weak inspiratory muscle, and in patients with defective medullary breathing pattern generators. This fuels the notion that the human ventilatory drive during wakefulness often results from a corticosubcortical cooperation, and opens new avenues to study certain ventilatory and speech disorders.

Use of growth hormone in the treatment of pediatric burns

Hypermetabolic response is characterized by a hyperdynamic circulatory response, with increased body temperature; increased oxygen and glucose consumption; increased carbon dioxide production; hyperglycemia (raised blood sugar levels); peripheral insulin resistance; glycogenolysis, proteolysis, and lipolysis (i.e. the breakdown of glycogen, protein, and lipids, respectively); the loss of lean body mass; and muscle and bone wasting. These symptoms can last for 1-2 years after the burn injury. Failure to satisfy overwhelming energy and protein requirements results in multiorgan dysfunction and an increased susceptibility for infection and death. Immunocompromization and delayed wound healing usually result in severe sepsis, which is the most common direct cause of death in these patients. Nevertheless, providing adequate caloric and protein requirements alone was found to be insufficient to attenuate the hypermetabolic response efficiently. Thereby, various pharmacologic modalities to modulate metabolic response have become a corner stone in the management of severely burned patients. Recombinant growth hormone is the most frequently prescribed agent in pediatrics. This review will focus on the metabolic and immune responses to the use of recombinant growth hormone in pediatric burn patients. It will explore what is beyond growth hormone and the role of insulin-like growth factor-1 in modulation of immunity and apoptosis.

Indirect calorimetry in the pediatric ICU

Failure to accurately estimate energy requirements may result in an impaired recovery. Overfeeding has been associated with increased carbon dioxide production, respiratory failure, hyperglycemia and fat deposits in the liver, while underfeeding can lead to malnutrition, muscle weakness and impaired immunity.

Malignant hyperthermia: a review.

Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases such as halothane, sevoflurane, desflurane, isoflurane and the depolarizing muscle relaxant succinylcholine, and rarely, in humans, to stressors such as vigorous exercise and heat. The incidence of MH reactions ranges from 1:10,000 to 1: 250,000 anesthetics. However, the prevalence of the genetic abnormalities may be as great as one in 400 individuals. MH affects humans, certain pig breeds, dogs and horses. The classic signs of MH include hyperthermia, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, hyperkalaemia, muscle rigidity, and rhabdomyolysis, all related to a hypermetabolic response. The syndrome is likely to be fatal if untreated. An increase in end-tidal carbon dioxide despite increased minute ventilation provides an early diagnostic clue. In humans the syndrome is inherited in an autosomal dominant pattern, while in pigs it is autosomal recessive. Uncontrolled rise of myoplasmic calcium, which activates biochemical processes related to muscle activation leads to the pathophysiologic changes. In most cases, the syndrome is caused by a defect in the ryanodine receptor. Over 400 variants have been identified in the RYR1 gene located on chromosome 19q13.1, and at least 34 are causal for MH. Less than 1 % of variants have been found in CACNA1S but not all of these are causal. Diagnostic testing involves the in vitro contracture response of biopsied muscle to halothane, caffeine, and in some centres ryanodine and 4-chloro-m-cresol. Elucidation of the genetic changes has led to the introduction of DNA testing for susceptibility to MH. Dantrolene sodium is a specific antagonist and should be available wherever general anesthesia is administered. Increased understanding of the clinical manifestation and pathophysiology of the syndrome, has lead to the mortality decreasing from 80 % thirty years ago to <5 % in 2006.

Effects of lactone, ketone, and phenolic compounds on methane production and metabolic intermediates during anaerobic digestion.

Fruit waste is a potential feedstock for biogas production. However, the presence of fruit flavors that have antimicrobial activity is a challenge for biogas production. Lactones, ketones, and phenolic compounds are among the several groups of fruit flavors that are present in many fruits. This work aimed to investigate the effects of two lactones, i.e., γ-hexalactone and γ-decalactone; two ketones, i.e., furaneol and mesifurane; and two phenolic compounds, i.e., quercetin and epicatechin on anaerobic digestion with a focus on methane production, biogas composition, and metabolic intermediates. Anaerobic digestion was performed in a batch glass digester incubated at 55 °C for 30 days. The flavor compounds were added at concentrations of 0.05, 0.5, and 5 g/L. The results show that the addition of γ-decalactone, quercetin, and epicathechin in the range of 0.5-5 g/L reduced the methane production by 50 % (MIC50). Methane content was reduced by 90 % with the addition of 5 g/L of γ-decalactone, quercetin, and epicathechin. Accumulation of acetic acid, together with an increase in carbon dioxide production, was observed. On the contrary, γ-hexalactone, furaneol, and mesifurane increased the methane production by 83-132 % at a concentration of 5 g/L.