14 research outputs found
Pulsed corona for breaking up air bubbles in water
The injection of gas into H2O, through a hollow needle gives a stream of bubbles. These bubbles can be effectively broken up by application of high-voltage pulses. This mechanism works in demineralized H2O and even in conducting tap H2O if the pulses have a short rise time. Bubble diams. down to at least 50 mm can be obtained. The pulse source uses either a high-voltage tetrode or a spark gap as switching element. Extremely small bubbles are produced at a high rate and a low power input. Applications of this method can be found in the chem. process technol. [on SciFinder (R)
Pulsed corona for breaking up air bubbles in water
The injection of gas into H2O, through a hollow needle gives a stream of bubbles. These bubbles can be effectively broken up by application of high-voltage pulses. This mechanism works in demineralized H2O and even in conducting tap H2O if the pulses have a short rise time. Bubble diams. down to at least 50 mm can be obtained. The pulse source uses either a high-voltage tetrode or a spark gap as switching element. Extremely small bubbles are produced at a high rate and a low power input. Applications of this method can be found in the chem. process technol. [on SciFinder (R)
Living with the physical and mental consequences of an ostomy:A study among 1–10-year rectal cancer survivors from the population-based PROFILES registry
Background This study examined the physical and mental consequences of an ostomy among 1–10-year rectal cancer survivors. Methods Patients with rectal cancer diagnosed from 2000 to 2009, as registered in the population-based Eindhoven Cancer Registry, received a questionnaire on quality of life (QOL; EORTC QLQ-C30), disease-specific health status (EORTC QLQ-CR38), depression and anxiety (HADS), illness perceptions (Brief Illness Perception Questionnaire), and health care utilization; 76% (n = 1019) responded. Results A total of 408 (43%) rectal cancer survivors had an ostomy at survey and they reported a statistically significant and clinically relevant lower physical, role, and social functioning, and global health status/QOL but fewer problems with constipation and diarrhea compared with those without an ostomy. Also, they had a significantly worse body image, more male sexual problems, and fewer gastrointestinal problems although these differences were not clinically relevant. No differences regarding the prevalence of symptoms of anxiety and depression were found. Survivors with an ostomy believed that their illness have significantly more serious consequences, will last longer (clinically relevant), and were more concerned about their illness compared with those without an ostomy. Survivors with an ostomy visited their medical specialist, but not their general practitioner, significantly more often. Also, they more often received additional support after cancer treatment. Conclusions Rectal cancer survivors with an ostomy have a lower QOL, worse illness perceptions, and a higher health care consumption compared with those without an ostomy 1–10 years after diagnosis
The Minor Structural Difference between the Antioxidants Quercetin and 4'O-Methylquercetin Has a Major Impact on Their Selective Thiol
Antioxidants act as intermediates by picking up the high unselective reactivity of radicals and transferring it to other molecules. In this process the reactivity is reduced and becomes selective. This channeling of the reactivity can cause selective toxicity. The antioxidant quercetin is known to channel the reactivity towards thiol groups. The present study compares the thiol reactivity of quercetin with that of 4'O-methylquercetin (tamarixetin) towards creatine kinase (CK), a vital protein that contains a critical thiol moiety. Our results showed that oxidized quercetin and oxidized tamarixetin both adduct CK, which then loses its enzymatic function. Ascorbate, an important representative of the antioxidant network, is able to prevent adduction to and thus the inhibition of the enzyme by tamarixetin but not by quercetin. Apparently, tamarixetin is less thiol toxic than quercetin, because—rather than adduction to CK—tamarixetin quinone prefers to pass reactivity to the antioxidant network, i.e., to ascorbate. The findings exemplify that radical scavenging flavonoids pick up the reactivity of radicals and act as a pivot in directing the way the reactivity is channeled. A mere minor structural difference of only one methyl moiety between quercetin and tamarixetin appears to have a high impact on the selective, thiol toxicity
Adjuvant Chemoradiotherapy for Non-Pretreated Gastric Cancer
Biological, physical and clinical aspects of cancer treatment with ionising radiatio
The flavonoid 7-mono-O-(beta-hydroxyethyl)-rutoside is able to protect endothelial cells by a direct antioxidant effect
The flavonoid 7-mono-O-(beta-hydroxyethyl)-rutoside (monoHER) is an effective protector against doxorubicin induced toxicity which has been related to the antioxidant activity of monoHER. The present study examines the potential relevance of the direct scavenging activity of the flavonoid. The potency of the direct antioxidant effect was confirmed by its instantaneous protection against intracellular oxidative stress in human umbilical vein endothelial cells at therapeutically achievable concentrations (EC50= 60 nM) underpinning the involvement of a direct scavenging activity. This direct effect of monoHER is substantiated by (i) its site specific scavenging effect, i.e. on a molecular level monoHER is positioned at the location of radical formation, (ii) its position in the antioxidant network, i.e. on a biochemical level oxidized monoHER quickly reacts with ascorbate or glutathione, (iii) its location in the vascular system, i.e. on a cellular level monoHER is localized in the endothelial and smooth muscle cells in the vascular wall. It is concluded that the flavonoid monoHER can display a physiologically important direct antioxidant effect
Development of imaging-based risk scores for prediction of intracranial haemorrhage and ischaemic stroke in patients taking antithrombotic therapy after ischaemic stroke or transient ischaemic attack: a pooled analysis of individual patient data from cohort studies
Background Balancing the risks of recurrent ischaemic stroke and intracranial haemorrhage is important for patients treated with antithrombotic therapy after ischaemic stroke or transient ischaemic attack. However, existing predictive models offer insufficient performance, particularly for assessing the risk of intracranial haemorrhage. We aimed to develop new risk scores incorporating clinical variables and cerebral microbleeds, an MRI biomarker of intracranial haemorrhage and ischaemic stroke risk.Methods We did a pooled analysis of individual-patient data from the Microbleeds International Collaborative Network (MICON), which includes 38 hospital-based prospective cohort studies from 18 countries. All studies recruited participants with previous ischaemic stroke or transient ischaemic attack, acquired baseline MRI allowing quantification of cerebral microbleeds, and followed-up participants for ischaemic stroke and intracranial haemorrhage. Participants not taking antithrombotic drugs were excluded. We developed Cox regression models to predict the 5-year risks of intracranial haemorrhage and ischaemic stroke, selecting candidate predictors on biological relevance and simplifying models using backward elimination. We derived integer risk scores for clinical use. We assessed model performance in internal validation, adjusted for optimism using bootstrapping.Findings The included studies recruited participants between Aug 28, 2001, and Feb 4, 2018. 15 766 participants had follow-up for intracranial haemorrhage, and 15 784 for ischaemic stroke. Over a median follow-up of 2 years, 184 intracranial haemorrhages and 1048 ischaemic strokes were reported. The risk models we developed included cerebral microbleed burden and simple clinical variables. Optimism-adjusted c indices were 0.73 (95% CI 0.69-0.77) with a calibration slope of 0.94 (0.81-1.06) for the intracranial haemorrhage model and 0.63 (0.62-0.65) with a calibration slope of 0.97 (0.87-1.07) for the ischaemic stroke model. There was good agreement between predicted and observed risk for both models.Interpretation The MICON risk scores, incorporating clinical variables and cerebral microbleeds, offer predictive value for the long-term risks of intracranial haemorrhage and ischaemic stroke in patients prescribed antithrombotic therapy for secondary stroke prevention; external validation is warranted. Copyright (C) 2021 Elsevier Ltd. All rights reserved