•New Power-to-Gas system with thermal integration of co-electrolysis and methanation.•Different configurations modelled and analyzed in ASPEN Hysys™ environment.•Performance indexes for efficiency ...and quality of produced synthetic natural gas.•Effects of heat recovery and pressurization on system performance evaluation.•Thermal integration feasibility demonstration.
Performance of an innovative storage system for renewable energy, based on the Power-to-Gas concept are numerically predicted. The investigated system is composed by a high temperature co-electrolyzer of Solid Oxide Electrolyte Cell technology and an experimental methanation section, based on structured catalyst, suitable for high temperature operation. With the aim to thermally integrate high temperature co-electrolysis and methanation, a parametric thermodynamic analysis of the Power-to-Gas system is carried-out with a lumped-parameters approach, including all the thermal and electric energy consumptions. In particular, in order to optimize the system thermal balance of plant, various configurations involving internal heat recovery and pressurization of components are also considered. Numerical results are provided in terms of different performance indicators, such as electric-to-fuel conversion index, first law efficiency and second law efficiency and output-fuel quality indicators. The study demonstrates the possibility to thermally integrate the co-electrolyzer and the high-temperature methanation section achieving significant energy savings. Moreover, the calculated results show that the system set-up providing higher quality of the produced synthetic natural gas do not always lead to larger values in energy conversion efficiency. Eventually, advanced configurations of the Power-to-Gas system including heat recovery allow to achieve first-law efficiency up to values around 80–85% and second-law efficiency around 70–78%; a second methanation section based on conventional low-temperature reactors is included in the system and pressurization of the methanation section, or pressurization of the co-electrolysis section, is mandatory, in order to achieve large fraction of methane (up to 95–99%) in the produced synthetic fuel.
Chronic postsurgical pain (CPSP) can occur frequently after thoracic surgery.
This retrospective study aimed to determine CPSP prevalence, risk factors, neuropathic pain (NP) occurrence, and its ...impact on quality of life.
About 200 patients who underwent lung resection via minithoracotomy or thoracoscopy between January 2017 and December 2017 were assessed 4–12 months postoperatively via phone interview for chronic pain by a 0–10 Numeric Rating Scale, for NP using the Douleur Neuropathique 4 test, and for quality of life using a Short Form-36 (SF-36) Health Survey (Italian version).
CPSP incidence was 35% (n = 70 of 200; 95% CI 41–28) of which 31.5% (n = 22 of 70; 95% CI 41–21) was with NP. Only 10% of patients with CPSP reported severe chronic pain. According to univariate analysis, CPSP was associated to moderate and severe acute postoperative pain (P < 0.001), open surgery (P = 0.001), and female gender (P = 0.044). According to multivariable analysis, independent risk factors for CPSP development included moderate-to-severe acute postoperative pain occurrence (odds ratio 32.61; 95% CI 13.37–79.54; P < 0.001) and open surgery (odds ratio 6.78; 95% CI, 2.18–21.03; P = 0.001). NP incidence was higher in female patients (16% in women and 6% in men, respectively; P = 0.040). A significant decrease in all SF-36 Health Survey domain scores was recorded for patients with CPSP and NP (P < 0.001).
More than one of three patients who underwent lung resection could develop CPSP, frequently showing neuropathic component. Female gender reported a higher CPSP and NP incidence. Moderate-to-severe acute postoperative pain occurrence and open surgery seem to be independent risk factors for CPSP. Chronic pain and NP have a negative impact on quality of life, decreasing the SF-36 scores of all domains.
mGlu7 receptors are coupled to Gi/Go-proteins and activate multiple transduction pathways, including inhibition of adenylyl cyclase activity and stimulation of ERK1/2 and JNK pathways. mGlu7 ...receptors play an important role in cognition and emotion and are involved in stress-related disorders such as anxiety and depression and in susceptibility to convulsive seizures. In spite of these potential clinical implications, little is known on the mechanisms that regulate mGlu7-receptor signaling. Here we show that mGlu7 receptor-dependent signaling pathways were regulated in a complementary manner by different GRK subtypes, with GRK4 affecting the adenylyl cyclase and the JNK pathways, and GRK2 selectively affecting the ERK1/2 pathway. Additionally we found that the two isoforms of non-visual arrestins, i.e. β-arrestin1 and β-arrestin2, exerted opposite effects on mGlu7-receptor signaling, with β-arrestin1 positively modulating ERK1/2 and inhibiting JNK, and β-arrestin2 doing the opposite. This represents a remarkable example of “reciprocal regulation” of receptor signaling by the two isoforms of β-arrestin. Finally we found that β-arrestin1 amplified mGlu7 receptor-dependent ERK1/2 activation in response to L-AP4 (an orthosteric agonist), but not in response to AMN082 (an atypical mGlu7-receptor allosteric agonist). The different effect of β-arrestin1 on L-AP4- and AMN082-stimulated ERK1/2 phosphorylation is in line with the emerging concept of β-arrestin-biased agonists. The present study may open new perspectives in elucidating the physio-pathological roles of the mGlu7 receptor and may provide new insights for the possibility to develop specific (biased) agonists that can selectively activate different signaling pathways.
•We study for the first time the regulation of mGlu7-receptor signaling.•GRK4 but not GRK2 regulates mGlu7 receptor-dependent adenylyl cyclase and JNK.•GRK2 but not GRK4 regulates mGlu7 receptor-dependent ERK1/2 pathway.•β-arrestin1 upregulates ERK1/2 and inhibits JNK, β-arrestin2 does the opposite.•We demonstrate “reciprocal” mode of mGlu7-receptor regulation by GRKs and arrestins.
The main byproduct of the sugarcane industry, Saccharum officinarum L. bagasse (sugarcane bagasse, SCB), is widely used as lignocellulose biomass for bio-ethanol (EtOH) production. In this research ...study, SCB was pretreated by steam explosion (SE) method using two different impregnating agents: sulfur dioxide (SD) and hydrogen peroxide (HP). As matter of fact, the use of impregnating agents improves the performance of SE method, increasing the concentrations of fermentable sugars after enzymatic saccharification, and decreasing the inhibitor compounds produced during the steam pretreatment step. The aim of this study was to investigate and compare the use of the two impregnating agents in various SE-conditions in order to optimize pretreatment parameters. For every pretreatment condition, it has been evaluated: concentration of fermentable sugars, glucose and xylose yields, and the effects of the inhibitor compounds on enzymatic hydrolysis step. The obtained results allow to improve the efficiency of the whole process of bio-EtOH synthesis enhancing the amount of fermentable sugars produced and the eco-sustainability of the whole process. Indeed, the optimization of steam pretreatment leads to a reduction of energy requirements and to a lower environmental impact.
•SCB steam pretreatment is optimized by adding SO2 and H2O2.•Cellulose is more accessible to enzymatic hydrolysis•Fermentable sugar concentrations are increased•Evaluation of inhibitors effect has been performed..
Postoperative secondary hyperalgesia arises from central sensitization due to pain pathways facilitation and/or acute opioid exposure. The latter is also known as opioid-induced hyperalgesia (OIH). ...Remifentanil, a potent μ-opioid agonist, reportedly induces postoperative hyperalgesia and increases postoperative pain scores and opioid consumption. The pathophysiology underlying secondary hyperalgesia involves N-methyl-D-aspartate (NMDA)-mediated pain pathways. In this study, we investigated whether perioperatively infusing low-dose buprenorphine, an opioid with anti-NMDA activity, in patients receiving remifentanil infusion prevents postoperative secondary hyperalgesia.
Sixty-four patients, undergoing remifentanil infusion during general anaesthesia and major lung surgery, were randomly assigned to receive either buprenorphine i.v. infusion (25 μg h−1 for 24 h) or morphine (equianalgesic dose) perioperatively. The presence and extent of punctuate hyperalgesia were assessed one day postoperatively. Secondary outcome variables included postoperative pain scores, opioid consumption and postoperative neuropathic pain assessed one and three months postoperatively.
A distinct area of hyperalgesia or allodynia around the surgical incision was found in more patients in the control group than in the treated group. Mean time from extubation to first morphine rescue dose was twice as long in the buprenorphine-treated group than in the morphine-treated group: 18 vs 9 min (P=0.002). At 30 min postoperatively, patients receiving morphine had a higher hazard ratio for the first analgesic rescue dose than those treated with buprenorphine (P=0.009). At three months, no differences between groups were noted.
Low-dose buprenorphine infusion prevents the development of secondary hyperalgesia around the surgical incision but shows no long-term efficacy at three months follow-up.
The diaphragm is the most important respiratory muscle in humans, and the close relationship between inspired volume and diaphragmatic movement in normal subjects has led to investigations into ...diaphragmatic activity using ultrasound, during spontaneous breathing and sedative drug infusion.
A total of 36 consecutive patients undergoing diagnostic procedures under deep propofol sedation were studied. Ultrasound measurements included the following: diaphragmatic thickening end-inspiration (TEI) and end-expiration (TEE). Diaphragmatic thickening fraction (DTF) was calculated from (TEI - TEE) / TEE at various time points (at T0 basal; at T1 during propofol infusion; at T2 awakening). Oxygen was administered at 4 L/min, and oxygen saturation (SpO2), end tidal CO2 (EtCO2) and respiratory rate (RR) were recorded.
TEI, and TEE decreased by 26.7% and 17.4%, respectively, during propofol infusion (T0 versus T1) (P<0.001), and rapidly recovered at T2 (22.7% and 15.8%). At procedure end (T0 versus T2), TEI maintained a significant reduction (10%, P<0.001), whereas TEE recovered completely. DTF decreased by 56.7% at T1 (P<0.001) but increased by 76.9% (P=0.001) at T2. Recovery after awakening (T0 versus T2) did not reach the baseline value, with a 23.4% difference (P<0.001). SpO2 remained above 96% and EtCO2 below 43 mmHg with no desaturation episodes observed.
Our study showed that deep propofol sedation affects muscle activity in healthy patients. While diaphragmatic strength decreased during sedation, there was no clinically relevant effect on SpO2. The study also confirmed that ultrasound is suitable for measuring diaphragm activity during a normal clinical procedure.
Most investigators have attributed the reduced postoperative pain or anaesthetic drug requirements in patients receiving i.v. magnesium sulphate (MgSO4) infusion during spinal or general anaesthesia ...to central N-methyl-d-aspartate (NMDA) receptor magnesium (Mg) activity. In this study, we investigated how cerebrospinal fluid (CSF) Mg concentrations change after spinal anaesthesia, and whether peripherally infusing MgSO4 influences central Mg levels.
Forty-five patients undergoing continuous spinal anaesthesia for hip arthroplasty were randomly assigned to receive either i.v. MgSO4 at a dose of 50 mg kg−1 diluted in 100 ml 0.9% saline solution followed by 15 mg kg−1 h−1 for 6 h or saline at the same volume mean (sd) 64 (10) ml. The changes in CSF and serum total and ionized Mg concentrations were assessed at six time points before and after spinal anaesthesia. Secondary outcome variables included serum and CSF electrolytes and proteins.
Thirty-five patients completed the study. We found that spinal anaesthesia reduced total and ionized Mg concentrations in CSF by about 10%. Increasing serum Mg concentration over 80% of the baseline value left CSF Mg levels unchanged.
Spinal anaesthesia unexpectedly reduced CSF total and ionized Mg concentrations in patients undergoing hip arthroplasty, although the mechanism is unclear. The dose used for peripheral MgSO4 infusion in this study had no influence on central Mg concentrations in neurologically healthy patients undergoing spinal anaesthesia. If CSF Mg concentration is a reliable marker of Mg brain bioavailability, peripherally infused MgSO4 during spinal anaesthesia is unlikely to influence central NMDA receptor activity.
Metabotropic glutamate (mglu) receptors are implicated in the regulation of many physiological and pathological processes in the CNS, including synaptic plasticity, learning and memory, motor ...coordination, pain transmission and neurodegeneration. Several recent studies have elucidated the molecular determinants of mglu receptor signaling and show that several mechanisms acting at different steps in signal propagation are involved. We attempt to offer an integrated view on how homologous and heterologous mechanisms regulate the initial steps of signal propagation, mainly at the level of mglu-receptor–G-protein coupling. Particular emphasis is placed on the role of phosphorylation mechanisms mediated by protein kinase C and G-protein-coupled receptor kinases, and on the emerging importance of some members of the regulators of G-protein signaling family, such as RGS2 and RGS4, which facilitate the GTPase activity that is intrinsic to the α-subunits of G
q and G
i.
Noninvasive positive-pressure ventilation is a safe and effective means of improving gas exchange in patients with many types of acute respiratory failure.
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For example, in patients with acute ...exacerbations of chronic obstructive pulmonary disease and hypercapnic respiratory failure, adding noninvasive ventilation to standard therapy decreased the need for endotracheal intubation
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and reduced mortality.
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Similarly, noninvasive continuous positive airway pressure was effective in patients with cardiogenic pulmonary edema, particularly those with hypercapnia.
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In patients with various forms of acute hypoxemic respiratory failure (pneumonia, congestive heart failure, chest-wall impairment, and so forth),
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this therapy slightly decreased the rate of . . .
Although anaesthetics are known to alter microcirculation no study has, to our knowledge, documented changes in human skeletal microcirculatory function during general anaesthesia.
Forty-four ...patients undergoing maxillofacial surgery at a university hospital were prospectively randomized to receive general anaesthesia with remifentanil combined with propofol or sevoflurane. Muscle microcirculation was investigated with near-infrared spectroscopy (NIRS) before general anaesthesia was induced and 30 min later. An NIRS device (NIMO, Nirox) was used to quantify calf deoxyhaemoglobin HHb, oxyhaemoglobin HbO2, and total haemoglobin HbT concentrations, coupled to a series of venous and arterial occlusions to measure calf blood flow, muscle oxygen consumption, calf vascular resistance, microvascular compliance, and haemoglobin resaturation rate (RR).
In both the groups, general anaesthesia induced marked changes in muscle microcirculation: the tissue blood volume increased (+33% in remifentanil–sevoflurane and +45% with remifentanil–propofol groups), microvascular resistance decreased (−31% and −38%, respectively), and the post-ischaemic haemoglobin RR decreased (−48% and −36%, respectively). In the remifentanil–propofol group, the muscle blood flow increased (P<0.001), whereas in the remifentanil–sevoflurane group microvascular compliance and muscle oxygen consumption decreased (P<0.01).
Remifentanil-based general anaesthesia with propofol or sevoflurane altered the muscle microcirculation in different ways. Quantitative NIRS, a technique that takes into account the optical tissue properties of the individual subject, can effectively measure these changes non-invasively.
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