Oxygen Tension Research Articles

Personalized intraoperative arterial pressure management and mitochondrial oxygen tension in patients having major non-cardiac surgery: a pilot substudy of the IMPROVE trial.

The "Cellular Oxygen METabolism" (COMET) system (Photonics Healthcare, Utrecht, The Netherlands) non-invasively measures mitochondrial oxygen tension (mitoPO2) in the skin. The effects of general anesthesia and major non-cardiac surgery on mitoPO2 remain unknown. In this pre-planned pilot substudy of the "Intraoperative blood pressure Management based on the individual blood PRessure profile: impact on postOperatiVE organ function" (IMPROVE) trial, we measured mitoPO2 from induction of general anesthesia until the end of surgery in 19 major non-cardiac surgery patients (10 assigned to personalized and 9 to routine intraoperative arterial pressure management). In the overall cohort, the median (25th to 75th percentile) preoperative awake mitoPO2 was 63 (53 to 82) mmHg and mitoPO2 after induction of general anesthesia was 42 (35 to 59) mmHg. The intraoperative average mitoPO2 was 39 (30 to 50) mmHg. Thirteen patients (68%) had intraoperative mitoPO2 values below 20mmHg and the median percentage of surgical time with mitoPO2 < 20mmHg was 17 (0 to 31)%. MitoPO2 was weakly correlated with mean arterial pressure (repeated measures correlation (rrm(n); rrm(984) = 0.26, 95% confidence interval 0.20 to 0.32; P < 0.001), but not meaningfully with heart rate (rrm(984) = -0.05, 95% confidence interval -0.11 to 0.01; P = 0.117). There was no important difference in intraoperative average mitoPO2 between patients assigned to personalized or to routine intraoperativearterial pressure management (P = 0.653). MitoPO2 under general anesthesia was about a quarter lower than preoperative awake mitoPO2, substantially fluctuated during major non-cardiac surgery, and transiently decreased below 20mmHg in about two-thirds of the patients. Personalized - compared to routine - intraoperative arterial pressure management did not increase intraoperative mitoPO2. Whether intraoperative decreases in mitoPO2 are clinically meaningful warrants further investigation.

Application of a novel extracorporeal membrane oxygenation system in awake Hu sheep under various durations

BackgroundExtracorporeal membrane oxygenation (ECMO) provides effective support for respiratory and circulatory functions and stands as an essential means in the management of life-threatening conditions. This study aimed to evaluate the safety and efficacy of a novel ECMO system in awake sheep models across various support durations.MethodsTen healthy Hu sheep were divided into venovenous (VV) and venoarterial (VA) groups, further categorized into short, medium, and long-term observation subgroups. Vital signs and blood indices were meticulously monitored. The integrity of heparin coatings and thrombosis in the ECMO system were assessed at indicated time points, followed by histopathological analysis.ResultsAll ten sheep survived to their planned endpoints under awake ECMO, exhibiting stable vital signs without notable reductions in blood cells. With the support of ECMO, all sheep demonstrated a significant increase in partial pressure of oxygen (PO2) and maintained oxygen saturation (SO2) between 99.8 and 100%. The heparin coating remained relatively intact even after prolonged ECMO operation. Anatomical observations and pathological histology analyses of major organs revealed no apparent abnormalities.ConclusionsIn healthy Hu sheep models with different maintenance periods, the novel ECMO support in awake state demonstrated high safety and feasibility.

Clinical characteristics and prognosis of amyopathic dermatomyositis patients with interstitial lung disease: insights from a retrospective cohort

IntroductionThe diagnosis of amyopathic dermatomyositis with interstitial lung disease (ADM-ILD) is challenging due to the lack of typical skin features and overlapping syndromes. We aimed to determine the characteristics and prognosis of patients with ADM-ILD to further guide their clinical management.MethodsA retrospective cohort study comprising 190 Chinese patients diagnosed with interstitial lung disease (ILD) was conducted. Patients were stratified into four groups using the Sontheimer criteria and predominant high-resolution computed tomography (HRCT) patterns. Demographic features, clinical presentation, laboratory parameters, duration of ILD, and follow-up data were analysed.ResultsThere were significant differences in the clinical parameters among the 190 patients with ILD in the amyopathic dermatomyositis (ADM, n = 69) and control (n = 121) groups. The ADM with nonspecific interstitial pneumonia (NSIP) group (n = 46) presented increased haemoglobin (125.93 ± 12.91 g/L, p = 0.005), creatine kinase-MB (15.19 ± 8.58 U/L, p < 0.001), and partial pressure of oxygen (93.08 ± 26.20 mmHg, p = 0.003) levels and decreased β2-microglobulin (2.61 ± 1.21 mg/L, p = 0.039) levels compared to the control-NSIP group (n = 92). The ADM with organizing pneumonia (OP) group (n = 23) had a greater percentage of females (7/16, p = 0.023) and higher alanine aminotransferase (30.30 ± 20.67 U/L, p = 0.039) and aspartate aminotransferase (53.35 ± 65.86 U/L, p = 0.003) levels than the control-OP group (n = 29). Both the ADM-NSIP and OP groups presented elevated lactate dehydrogenase (LDH) levels (290.61 ± 86.49 U/L, p = 0.009; 317.35 ± 181.32 U/L, p = 0.003, respectively) and increased anti-nuclear antibody (ANA) positivity rates (82.61%, p = 0.01; 73.91%, p < 0.001, respectively). Notably, 81.26% of patients with ADM-NSIP/OP had LDH levels above normal. The serum LDH levels could be used to distinguish patients with ADM-NSIP/OP (sensitivity: 73.91%, specificity: 82.64%). Survival was shorter among patients with ADM-OP than among control patients (p = 0.002). Cox multivariate analysis revealed that age (p = 0.002), smoking status (p = 0.011), anti-melanoma differentiation-associated gene 5 (MDA5) antibody (p = 0.017), and white blood cell count (p = 0.004) were independent predictors of shorter survival.ConclusionsElevated serum LDH levels in patients predominantly presenting with NSIP or OP patterns may indicate the presence of ADM-ILD. The identified prognostic factors underscore the importance of early detection and personalized management strategies for optimizing outcomes in patients with ADM-ILD.

Phase Equilibria and Trace Element Deportments in Fe–O–Al2O3–SiO2 Slags and Molten Copper Matte at 1473 K (1200 °C), Fixed p(O2) and p(SO2), and Silica/Magnetite Saturation

Abstract Understanding the role of major components of electric waste during smelting of these materials to recover valuable trace metals is poorly constrained by experimental data. In this study, phase equilibria and trace element deportments were studied at 1473 K (1200 °C) in conditions of combined sulfide concentrate and electric and electronic equipment waste processing in batchwise submerged lance smelting. In this system, liquid slag domain is limited by silica and magnetite saturation boundaries or primary phase fields at all alumina concentrations from alumina-free slags to silica-spinel double saturation. The impact of alumina concentration in slag at fixed oxygen and sulfur dioxide partial pressures on the distributions of Ag, Cu, In, Pb, and Sn was studied. Elemental concentrations in slag, matte, and solid magnetite (a Fe–Al spinel solid solution) were measured using electron probe microanalysis and laser ablation-ICP-mass spectrometry techniques. The observed impact of alumina on the distribution coefficient of silver, copper, and indium favored the matte phase at silica and magnetite saturation but lead and tin behaved differently within different primary phase fields as a function of alumina concentration.

Experimental validation of a novel portable device integrating an oxygen concentrator and a ventilation module for patients with ALI/ARDS in low resource countries: a cross-over non-inferiority trial.

This non-inferiority, cross-over study aims to evaluate a novel proof-of-concept portable respiratory support device specifically designed for low-resource settings. The device integrates a ventilation module and an oxygen concentrator. We studied twelve 4-week-old piglets with a mean weight of 8.4 kg before and after oleic acid-induced acute respiratory distress syndrome (ARDS). In each condition, animals received 1-h pressure control ventilation using a conventional ventilator (Servo-i, Getinge, SE) and the experimental ventilator in random sequence. Arterial blood gas analysis was performed every half-hour to adjust the ventilator settings. The primary outcome was partial pressure of oxygen to FiO2 ratio (P/F) with a non-inferiority margin of 50 mmHg. P/F did not differ significantly between the experimental and the control ventilation at baseline (459.6(30.9) vs 454.4(28.6) mmHg) and during ARDS condition (165.1(36.9) vs 182.5(48.4) mmHg). The upper 95% CI of the difference between P/F after ventilation using the control and the experimental ventilator was 37.3 and 44.1 mmHg during baseline and ARDS, respectively. The experimental device was not inferior to a conventional ventilator during both baseline and ARDS conditions, suggesting that it can provide adequate treatment to infants with mild to moderate hypoxemic lung disease in resource-limited care settings. This manuscript provides the results of a non-inferiority study that compared a novel proof-of-concept respiratory support device, integrating a ventilation module and an oxygen concentrator, specifically designed for respiratory support in low-resource settings, with a conventional pediatric intensive care ventilator in an oleic-acid model of acute lung injury. Our results showed that the experimental device was non-inferior to a conventional ventilator, suggesting that it can provide adequate treatment to infants with mild to moderate hypoxemic lung disease in resource-limited care settings. The developed solution can also be relevant for other applications, including home mechanical ventilation.

The Effectiveness of Planned Teaching Programme on Knowledge Regarding Arterial Blood Gas Analysis among Undergraduate Nursing Students in Jhalawar District

An Arterial Blood Gas (ABG) test is a relatively swift and low-risk method that helps healthcare professionals obtain information on oxygen saturation, acid-base balance, partial pressure of oxygen, partial pressure of carbon dioxide, metabolic parameters, and arterial oxygen saturation 1OBJECTIVES1. To assess the existing knowledge regarding Arterial Blood Gas (ABG) analysis among undergraduate nursing students at a selected nursing college.2. To evaluate the effectiveness of a planned teaching program on Arterial Blood Gas (ABG) analysis among undergraduate nursing students at a selected nursing college.3. To determine the association between pre-test knowledge scores and selected demographic variables.Material and Method:A quasi-experimental one-group pre-test post-test design was used. A total of 125 samples were selected using the probability simple random sampling method. A structured questionnaire consisting of 30 items was administered as a pre-test on the first day,followed by planned teaching, and a post-test was conducted on the seventh day. The reliability coefficient (r) of the questionnaire was 0.80, which is greater than 0.7, indicating that it was reliable. The conceptual framework was based on the AdaptationTheory developed by Sr. Callista Roy (1976), incorporating input, processes, effectors, output, and feedback. Result and Conclusion:In the results of the structured questionnaire, it was found that 29.6% ofundergraduate nursing students had poor knowledge, 65.6% had average knowledge, and4.8% had good knowledge regarding Arterial Blood Gas (ABG) analysis. The post-testknowledge score findings showed an improvement in the knowledge of undergraduatenursing students regarding ABG analysis. After the intervention, 41.6% of undergraduatenursing students had average knowledge, while 54.4% had good knowledge scoresregarding ABG analysis. This suggests a marked increase in post-test knowledge scores,indicating that the planned teaching was effective. The chi-square test computed betweenpre-test knowledge and selected variables showed that knowledge was not dependent onage, gender, qualification, or previous knowledge.

Functional outcomes of inspiratory muscle training in elderly with intensive care unit-acquired weakness and severe walking disability.

Intensive care unit acquired-weakness syndrome (ICUAWS) leaves several complications in functional movements of patients such as severe walking disability. Assessment of functional outcomes of 1-month inspiratory muscle training (IMT) in elderly with ICUAWS and severe walking disability was our aim. The design, setting, participants, and intervention. This study is a randomized controlled trial. ICUAWS patients who complained of severe walking disability on the Modified Functional Ambulatory Category Test (MFACT) were randomly assigned into the IMT group or control group, n = 20 for each group. Both groups received the traditional physical therapy program. The results showed that the post-therapy between-group comparison of ICUAWS sufferers/groups' parameters showed a significant improvement toward the IMT group in six-minute walk test, inspiratory and expiratory muscle strength, forced vital capacity, time up and go test, 10-m walk test, forced expiratory volume in the first second, 30-s sit-to-stand test, partial pressure of arterial blood oxygen and carbon dioxide, MFACT, oxygen saturation of arterial blood, physical, and mental summary of short form 36. In conclusion, IMT improves functional outcomes in ICUAWS patients with walking disability. The clinical trial ID of this ICUAWS trial is NCT06210763.

Facile synthesis of vanadium oxide thin films by atomic layer deposition and post-annealing

We report the facile synthesis of vanadium oxide (VOx) thin films on sapphire substrates by atomic layer deposition (ALD) and post-annealing. Amorphous VOx thin films are grown by ALD employing tetrakis[ethylmethylamino]vanadium and ozone as precursors. Subsequent post-annealing of the as-grown VOx thin films at 500 °C in atmospheres of air, 1 Pa O2, and vacuum (10−4 Pa) could, respectively, result in the crystallization of V2O5, VO2, and V2O3 phases, as verified by x-ray diffraction and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) reveals that the valence states of vanadium in the annealed thin films exhibit dramatic changes with the variation of annealing atmosphere toward the targeted phases. The VO2 thin film exhibits a sharp metal–insulator transition (MIT) near 340 K with a resistivity change exceeding three orders of magnitude. The V2O3 thin film features a characteristic MIT with obvious thermal hysteresis between the cooling and warming processes, whereas the V2O5 thin film is highly insulating. The spectral weight near the Fermi level revealed by the XPS in the valence band region coincides with the changes of VOx phases and consequent transport properties due to post-annealing. Our results demonstrate that the combination of ALD and post-annealing provides a facile method for the synthesis of multivalent VOx thin films for practical applications.

Lianhua Qingke Tablet in severe pneumonia: Clinical efficacy and immunoregulatory mechanisms.

Lianhua Qingke (LHQK), a traditional Chinese medicine, has shown efficacy in treating acute and chronic bronchitis and bronchiolitis. However, the specific mechanism underlying the therapeutic effects of LHQK on severe pneumonia is not clear. Severe pneumonia remains a critical health challenge, particularly in cases progressing to sepsis and septic shock, where host immune responses become dysregulated or dysfunctional. This study aims to evaluate the immunomodulatory effects of LHQK in severe pneumonia. This research examined LHQK's therapeutic and immunomodulatory mechanisms in patients with severe pneumonia and a lipopolysaccharide (LPS)-induced mouse model of severe pneumonia. Patients with severe pneumonia were randomized into three groups: basal treatment, LHQK-Low dose (12 tablets/day), and LHQK-High dose (24 tablets/day). BALB/c mice were categorized into four groups: control, model, LHQK-Low dose (3.7mg/kg), and LHQK-High dose (7.4mg/kg). Clinical efficacy was evaluated by assessing parameters including the value and rate of change in APACHE II score, improvement in chest X-ray or CT, partial pressure of oxygen (PO2), oxygen saturation in arterial blood (SaO2), oxygenation index (OI), and the length of hospitalization after 7 days of treatment. The viscosity of sputum was measured by viscosimeter. Moreover, lung histopathology, airway barrier integrity, and immune cells in BALF, were assessed using hematoxylin and eosin staining, immunostaining, and Wright-Giemsa staining. Cytokine levels were measured using Luminex assay and Olink, while pulmonary immune cell patterns were analyzed using multiplex fluorescence and Cytometry by Time-Of-Flight (CyTOF). In comparison to the basal treatment group of patients, LHQK treatment exhibited a reduction in the severity of severe pneumonia and inflammatory status, as evidenced by observations on Chest X-ray or CT scans. Additionally, LHQK treatment led to an elevation in OI, PO2, and SaO2 levels, and notably, a decreased duration of hospitalization. Further analysis revealed that LHQK enhanced the integrity of the airway epithelial barrier, reduced the viscosity of sputum, and significantly decreased inflammatory cells infiltration. The application of Luminex and Olink assay further confirmed the inhibitory impact of LHQK on the cytokine storm in mice. Moreover, multiplex fluorescence and CyTOF analysis demonstrated that LHQK effectively suppressed the activation of monocyte derived macrophages, neutrophils, and Treg cells, while preserved the levels of alveolar macrophages, B cells, and CD4+ and CD8+ T lymphocytes, therefore restoring immune homeostasis within the lung of severe pneumonia. These findings significantly substantiate the potential clinical application of LHQK in severe pneumonia treatment. LHQK demonstrates therapeutic efficacy in severe pneumonia by maintaining structural integrity, suppressing cytokine storms, enhancing intrinsic immunity, reversing T cell exhaustion, and correcting lung immune disorders. These findings significantly substantiate LHQK's potential clinical application in severe pneumonia treatment.

Thermally Dependent Metastability of Indium-Tungsten-Oxide Thin-Film Transistors

Abstract Indium tungsten oxide (IWO) has been investigated as an oxide semiconductor candidate for next-generation thin-film transistors (TFTs). Bottom-gate TFTs were fabricated with a 30-nm IWO channel material sputter-deposited with oxygen partial pressure (PO2) ranging from 2.5% to 10% of the total ambient pressure. Annealing was conducted at temperatures ranging from 100ºC to 275ºC. Device transfer characteristic measurements revealed a pronounced interaction between the sputter PO2 setting and passivation annealing conditions. Devices annealed at 100ºC in air ambient demonstrated characteristics with a strong dependence on PO2, attributed to differences in oxygen vacancy defects and semiconductor electronic properties. Devices annealed at 200ºC in air ambient demonstrated characteristics like those of unannealed devices, with operation far in depletion mode. Donor state passivation is possible following additional annealing at 275ºC in air, with reduced sensitivity to the initial sputter PO2 setting. A hypothesis on the mechanism of metastability is proposed.

Hypoxia as a critical player in extracellular vesicles-mediated intercellular communication between tumor cells and their surrounding microenvironment.

In the past years, increasing attention has been paid to the role of extracellular vesicles (EVs) as mediators of intercellular communication in cancer. These small size particles mediate the intercellular transfer of important bioactive molecules involved in malignant initiation and progression. Hypoxia, or low partial pressure of oxygen, is recognized as a remarkable feature of solid tumors and has been demonstrated to exert a profound impact on tumor prognosis and therapeutic efficacy. Indeed, the high-pitched growth rate and chaotic neovascular architecture that embodies solid tumors results in a profound reduction in oxygen pressure within the tumor microenvironment (TME). In response to oxygen-deprived conditions, tumor cells and their surrounding milieu develop homeostatic adaptation mechanisms that contribute to the establishment of a pro-tumoral phenotype. Latest evidence suggests that the hypoxic microenvironment that surrounds the tumor bulk may be a clincher for the observed elevated levels of circulating EVs in cancer patients. Thus, it is proposed that EVs may play a role in mediating intercellular communication in response to hypoxic conditions. This review focuses on the EVs-mediated crosstalk that is established between tumor cells and their surrounding immune, endothelial, and stromal cell populations, within the hypoxic TME.

PbSO4 reaction mechanism in oxygen and reduction atmospheres during co-smelting process with primary lead material.

At present, lead-containing wastes have increasingly become the raw materials together with primary lead concentrate for lead production to meet the ever-increasing lead demand market. PbSO4 is the dominant component in the lead-containing wastes, nevertheless, its reaction behavior during lead smelting is not sufficiently investigated. This study investigated PbSO4 decomposition behaviors and phase transformation mechanisms at oxidizing and reductive atmospheres and various gas flow rates. The investigations reveal that increasing the temperature and decreasing the oxygen partial pressure of the decomposition atmosphere can accelerate PbSO4 decomposition degree. PbSO4 decomposition intensity under different atmospheres follows the order of reducing atmosphere>inert atmosphere>oxidizing atmosphere. PbSO4 decomposition path was identified: at a non-reductive atmosphere, the decomposition of PbSO4 belongs to a multi-step decomposition process, PbSO4 gradually decompose into xPbO·PbSO4 (x=1, 2, 4 in turn) and finally PbO. At a reductive atmosphere, the multi-step decomposition process was accelerated significantly, at the same time, the reduction decomposition path PbSO4→PbS was increasingly dominant with the extension of decomposition time. PbS and Pb were generated successively. Therefore, a suitable reducing atmosphere is suggested to co-smelt PbSO4-bearing wastes in primary lead smelting furnace.

Individual FiO2 guided by SPO2 prevents hyperoxia and reduces postoperative atelectasis in colorectal surgery: A randomized controlled trial.

To determine whether individualized fraction of inspired oxygen (iFiO2) improves pulmonary atelectasis after elective laparoscopic colorectal surgery relative to 60% FiO2. This was a single-center, prospective, randomized study. This study was conducted in a single tertiary care hospital in China. A total of 84 eligible inpatients who underwent elective laparoscopic colorectal surgery between August 2021 and May 2022 were included in the study. The patients were randomly assigned to receive either a fixed fraction of inspiration oxygen (fFiO2 group) or individualized FiO2 based on physiological SpO2 (iFiO2 group). The primary outcome was the lung ultrasound score (LUS) at 30min after extubation. Secondary outcomes included the length of hospital stay, admission to the intensive care unit, the length of post-anesthetic care unit stay, the ratio of lung capacity on the third day after surgery compared with before surgery, the incidence of nausea and vomiting, and surgical site infections after surgery. Additionally, the airway plate pressure, airway peak pressure, pulmonary dynamic compliance, PaO2, oxygenation index, alveolar-arterial oxygen tension gradient (A-aDO2), and pulmonary shunt fraction (Qs/Qt) were considered. The LUS was significantly lowered in the iFiO2 group (5 [4, 7]) compared with the fFiO2 group (8 [4, 10]) (P=0.03). Based on the criterion for determining atelectasis, 25 patients (62.5%) in the fFiO2 group experienced significant atelectasis compared with 15 patients (37.5%) in the iFiO2 group (P=0.025). At the end of surgery, PaO2, A-aDO2, and Qs/Qt were significantly reduced in patients in the iFiO2 group compared with those in the fFiO2 group. The use of iFiO2 during operation significantly reduces the LUS and pulmonary atelectasis in patients undergoing laparoscopic colorectal surgery under general anesthesia. ChiCTRT2100049615.

Association Between Lung Ultrasound Score and PaO2/FiO2 Ratio in Neonatal Pneumonia: A Prospective Cohort Study.

Lung ultrasonography (LUS) is increasingly used to assess pulmonary diseases due to its safety and convenience. This study aimed to find out the association between the LUS score and the PaO2/FiO2 ratio in neonatal pneumonia. This study prospectively enrolled 57 neonates with suspected pneumonia. LUS score (range 0-48) was evaluated by assessing 12 lung regions. The PaO2/FiO2 ratio was calculated by dividing the arterial oxygen partial pressure by the fraction of inspired oxygen from blood gas analysis. Correlations were analyzed using Pearson's correlation coefficient. Birth weight ranged 1 100-4 500 g (median 2 925 g), gestational age 27-41 weeks (median 37 weeks), and age 1-28 days (median 1 day). The LUS score was significantly correlated with the PaO2/FiO2 ratio (r = 0.758, p < 0.001), arterial oxygen partial pressure (r = 0.731, p < 0.001), partial pressure of carbon dioxide (r = 0.213, p < 0.001), and oxygen saturation (r = 0.196, p < 0.001). Our study demonstrates significant correlations between the LUS score and blood gas analysis indices in neonatal pneumonia.

The current perspective of oxygen therapy and ventilatory support in acute heart failure Authors Yoga Waranugraha

Oxygen (O2) therapy in acute heart failure (AHF) is purposed to address hypoxemia and thereby avert irreversible harm to essential organs caused by cellular hypoxemia. The O2 therapy is recommended for patients with AHF who have an oxygen saturation (SpO2) level below 90% or an oxygen partial pressure (PaO2) below 60 mmHg. The initial strategy of O2 therapy in AHF involves administering O2 using the nasal, face mask, or non-rebreathing mask (NRBM). In more severe clinical conditions or respiratory distress, non-invasive positive pressure ventilation (NIPPV) or intubation with mechanical ventilation may needed. Keywords: acute heart failure, oxygen therapy, ventilation

Solubility of Gold in FeOx-SiO2-Al2O3 Slags at 1300°C

ABSTRACT Solubility of gold in copper-free alumina iron silicate slags in equilibrium with iron alumina spinel was studied using equilibration-quenching technique under controlled p(O 2) gas atmosphere at 1300°C. The gold concentration in slag was analyzed by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), which allowed elimination of the mechanical metal dispersion from the slag analyses. Thus, the data represent purely the chemically dissolved gold, and the dissolution in slag was shown to occur as AuO0.5 species at high oxygen partial pressures ≥10−7 atm. Contrary to earlier observations in (basaltic) iron-lean high-silica melts, the results indicate that gold solubility at low oxygen partial pressures, <10−7 atm, was no more decreasing but maintained at a minimum (log10LAu/s(Au) = 5.6–5.7). Even at the highest partial pressure of oxygen (=10−5 atm), the distribution coefficient was above log10LAu/s(Au) = 5.2, which suggests that mechanical dispersion containing gold causes by far the major source of gold loss in the copper and nickel matte smelting as well as in the secondary copper (‘black copper’) smelting operations.

Trajectory of the arterial-alveolar oxygen gradient in COPD for a decade.

Chronic respiratory failure (CRF) is a critical complication in patients with chronic obstructive pulmonary disease (COPD) and is characterized by an increase in the arterial-alveolar oxygen gradient (A-aDO2). The long-term trajectory and prognostic significance remain unclear. This study aimed to assess the prognostic impact of A-aDO2 and elucidate its trajectory over ten years. We enrolled 170 outpatients with COPD from a prospective cohort study. Arterial blood gas (ABG) analyses were conducted annually for ten years while monitoring the development of CRF. 157 patients completed the observation period, of whom 21 developed CRF (CRF group) and 136 did not (non-CRF group). In the CRF group, there was a gradual increase in A-aDO2 along with decreases in partial pressure of oxygen (PaO2) and partial pressure of carbon dioxide (PaCO2) over ten years, although there were no changes in the non-CRF group. The CRF group had higher baseline A-aDO2 and higher ΔA-aDO2 in the first year than the non-CRF group (3.76 vs. 0.42 Torr/year, p = 0.030). Kaplan-Meier analyses, and multivariate Cox proportional hazards analysis revealed that both baseline A-aDO2 and ΔA-aDO2 were significantly associated with the development of CRF. Retrospective tracking from the initiation of long-term oxygen therapy (LTOT) revealed significant increases in A-aDO2 from 5 years prior to LTOT initiation in the CRF group when compared to the non-CRF group. An increasing trend in A-aDO2 may be a significant sign for the future development of CRF. A transition of the annual change of A-aDO2 from a stable state to a deterioration phase can serve as a prognostic factor for developing CRF within 5 years.

Effects of intrathecal administration of sodium nitroprusside and nicardipine on cerebral pial microcirculation, cortical tissue oxygenation, and electrocortical activity in the early post-resuscitation period in a porcine cardiac arrest model.

Recent studies suggested intrathecal vasodilator administration as a therapy to mitigate post-ischemic cerebral hypoperfusion following cardiac arrest. We examined the effects of two commonly used intrathecal vasodilators, sodium nitroprusside (SNP) and nicardipine, on cerebral pial microcirculation, cortical tissue oxygen tension (PctO2), and electrocortical activity in the early post-resuscitation period using a porcine model of cardiac arrest. Thirty pigs were resuscitated after 14 min of untreated cardiac arrest. At 30 min after resuscitation from cardiac arrest, 30 pigs randomly received 4 mg of SNP, 4 mg of nicardipine, or saline placebo via subdural intracranial catheters and were observed for 5 h. Group effect and group-time interaction were assessed using linear mixed-effects models. The mean arterial pressure was lower in the nicardipine group (coefficient [95% confidence interval {CI}], -15.824 [-24.082 to -7.566]) and higher in the SNP group (coefficient [95%CI], 11.232 [2.974-19.490]) compared to the saline group. The percentage of pial arteriole diameter relative to the pre-arrest baseline value (coefficient [95% CI], 48.970 [13.884-84.057]), microvascular flow index (coefficient [95% CI], 0.296 [0.071-0.521]), and PctO2 (coefficient [95% CI], 26.926 [12.404-41.449]) were higher in the SNP group but not in the nicardipine group compared to the saline group. Amplitude-integrated electroencephalography amplitude recovery was faster in the SNP group (coefficient [95% CI], 1.149 [0.468-1.829]) but not in the nicardipine group compared to the saline group. In conclusion, intrathecal SNP but not nicardipine was effective in treating post-ischemic cerebral hypoperfusion after cardiac arrest.

Oxygenation improvement and duration of prone positioning are associated with ICU mortality in mechanically ventilated COVID-19 patients

BackgroundProne position has been diffusely applied in mechanically ventilated COVID-19 patients. Our aim is ascertaining the association between the physiologic response and the length of the first cycle of prone position and intensive care unit (ICU) mortality.MethodsInternational registry including COVID-19 adult patients who underwent prone positioning. We measured the difference for arterial partial pressure of oxygen to inspired fraction of oxygen ratio (PaO2/FiO2), ventilatory ratio, and respiratory system compliance (Crs) between baseline supine position and at either the end of the first cycle of prone position (Delta-PP) or re-supination (Delta-PostPP).ResultsWe enrolled 1816 patients from 53 centers. Delta-PP and Delta-PostPP for PaO2/FiO2 were both associated with ICU mortality [OR (95% CI) 0.48 (0.38, 0.59), and OR (95% CI) 0.60 (0.52, 0.68), respectively]. Ventilatory ratio had a non-linear relationship with ICU mortality for Delta-PP (p = 0.022) and Delta-PostPP (p = 0.004). Delta-PP, while not Delta-PostPP, for Crs was associated with ICU mortality [OR (95% CI) 0.80 (0.65, 0.98)]. The length of the first cycle of prone position showed an inverse relationship with ICU mortality [OR (95% CI) 0.82 (0.73, 0.91)]. At the multivariable analysis, the duration of the first cycle of prone position, Delta-PP and Delta-PostPP for PaO2/FiO2, and Delta-PostPP for ventilatory ratio were independently associated with ICU mortality.ConclusionIn COVID-19 patients with acute respiratory failure receiving invasive mechanical ventilation and prone positioning, the physiological response to prone position is associated with ICU mortality. Prolonging the duration of the first cycle of prone position is associated with improved survival.

Growth of 6 Inch Diameter β‐Ga2O3 Crystal by the Vertical Bridgman Method

A 6 inch β‐gallium oxide (β‐Ga2O3) single crystal is grown in the ⟨010⟩ direction using the vertical Bridgman (VB) method under an oxygen partial pressure of 50%. Although cracks are observed along the cleavage planes, crossed polarizer microscopy confirms the absence of grain boundaries in the wafers. X‐ray rocking curve measurements demonstrate a consistent level of crystal quality, with an average full width at half maximum of 22.56 arcsec. Observation of the quenched solid–liquid interface reveals a slightly convex shape. The actual growth rate, calculated from the experimental data, suggests that crystal growth does not fully keep pace with the crucible descent process. The effect of the furnace temperature gradient is investigated by comparing a higher gradient (4–15 °C cm−1) with a lower gradient (0.5–5 °C cm−1). The crystal grown under the higher gradient exhibits no grain boundaries, whereas those grown under the lower gradient shows grain boundaries and significant cracking, making it unsuitable for wafer processing. These results demonstrate the feasibility of growing 6 inch β‐Ga2O3 single crystals using the VB method and suggest that further optimization of conditions, including control of the temperature gradient, are essential to achieve higher quality and greater stability.