Closed-cycle gas flow system for cooling of high Tc d.c. SQUID magnetometers

A high Tc.d.c SQUID based magnetometer for magnetocardiography is currently under development at the University of Twente. Since such a magnetometer should be simple to use, the cooling of the system can be realized most practically by means of a cryocooler. A closed-cycle gas flow cooling system incorporating such a cooler has been designed, constructed and tested. The aimed resolution of the magnetometer is 0.1 pT Hz−1/2. The required operating temperature for the SQUIDs is 30 to about 77 K with a stability of 2 × 10−4 K Hz−1/2. After a cool-down time of 1–2 h, a stationary cooling power of at least 0.2 W is required. In the design, helium gas is cooled by a Leybold Heraeus RG 210 cryocooler, transported through a gas line, and subsequently passed through a heat exchanger on which SQUIDs can be installed. The lowest obtainable SQUID heat exchanger temperature is 31 ± 2 K. This can be reached in roughly 2–3 h with an optimal mass flow with respect to the cooling power of 6 × 10−6 kg s−1. At this mass flow the cooling power at the SQUID heat exchanger is 0.2 W at 42 K and roughly 1.2 W at 77 K. A temperature stability of 0.05 K was measured at a SQUID heat exchanger temperature of 54 K and a mass flow of 3 × 10kg s−5. The experience gained with this large cooling system will be used in the design of a smaller configuration cooling system, incorporating miniature Stirling cryocoolers. In this paper the design and the construction of the present closed-cycle system are described and test results are presented.\ud \u

Severe hypokalaemic paralysis and rhabdomyolysis due to ingestion of liquorice

Chronic ingestion of liquorice induces a syndrome with findings similar to those in primary hyperaldosteronism. We describe a patient who, with a plasma K+ of 1.8 mmol/l, showed a paralysis and severe rhabdomyolysis after the habitual consumption of natural liquorice. Liquorice has become widely available as a flavouring agent in foods and drugs. It is important for physicians to keep liquorice consumption in mind as a cause for hypokalaemic paralysis and rhabdomyolysis

Formate Over-Oxidation Limits Industrialization of Glycerol Oxidation Paired with Carbon Dioxide Reduction to Formate

Electrocatalytic CO2 reduction processes are generally coupled with the oxidation of water. Process economics can greatly improve by replacing the water oxidation with a more valuable oxidation reaction, a process called paired electrolysis. Here we report the feasibility of pairing CO2 reduction with the oxidation of glycerol on Ni3S2/NF anodes to produce formate at both anode and cathode. Initially we optimized the oxidation of glycerol to maximize the Faraday efficiency to formate by using design of experiments. In flow cell electrolysis, excellent selectivity (up to 90 % Faraday efficiency) was achieved at high current density (150 mA/cm2 of geometric surface area). Then we successfully paired the reduction of CO2 with the oxidation of glycerol. A prerequisite for industrial application is to obtain reaction mixtures with a high concentration of formate to enable efficient downstream separation. We show that the anodic process is limited in formate concentration, as Faraday efficiency to formate greatly decreases when operating at 2.5 M formate (∼10 w%) in the reaction mixture due to over-oxidation of formate. We identify this as a major bottleneck for the industrial feasibility of this paired electrolysis process.</p

Current anesthesia practice for preterm infants undergoing surgery for necrotizing enterocolitis:A European survey

Study objective: Necrotizing enterocolitis (NEC) is a life-threatening intestinal illness mostly affecting preterm infants, which commonly requires surgery. Anesthetic care for these patients is challenging, due to their prematurity and critical illness with hemodynamic instability. Currently, there are no guidelines for anesthetic care for these vulnerable patients. Therefore, this study aimed to describe current anesthesia practices across Europe for infants undergoing surgery for NEC. Design: Cross-sectional survey study. Participants: Anesthesiologists working in centers where surgery for NEC is performed across Europe. Measurements: A 46-item questionnaire assessing protocols for anesthesia practice, preoperative care, intraoperative care, postoperative care, and the respondent's opinion on the adequacy of anesthetic care for patients with NEC in their center. Main results: Out of the 173 responding anesthesiologists from 31 countries, approximately a third had a written standard protocol for anesthetic care in infants. Three quarters of the respondents screened all patients with NEC preoperatively, and a third structurally performed preoperative multidisciplinary consultation. For induction of general anesthesia, most respondents opted for intravenous anesthesia (n = 73, 43%) or a combination of intravenous and inhalation anesthesia (n = 57, 33%). For intravenous induction, they mostly used propofol (n = 58, 44%), followed by midazolam (n = 43, 33%) and esketamine (n = 42, 32%). For maintenance of anesthesia, inhalation anesthetic agents were more commonly used (solely: n = 71, 41%; in combination: n = 37, 22%), almost exclusively with sevoflurane. Postoperative analgesics mainly included paracetamol and/or morphine. Sixty percent of the respondents (n = 104) considered their anesthetic care for patients with NEC adequate. Suggestions for further improvement mainly revolved around monitoring, protocols, and collaboration. Conclusions: Anesthesia practice for infants undergoing surgery for NEC was highly variable. Most respondents considered the provided anesthetic care for patients with NEC adequate, but also recognized opportunities for further improvement, especially with regards to monitoring, protocols, and interdisciplinary collaboration.</p

Current anesthesia practice for preterm infants undergoing surgery for necrotizing enterocolitis:A European survey

Study objective: Necrotizing enterocolitis (NEC) is a life-threatening intestinal illness mostly affecting preterm infants, which commonly requires surgery. Anesthetic care for these patients is challenging, due to their prematurity and critical illness with hemodynamic instability. Currently, there are no guidelines for anesthetic care for these vulnerable patients. Therefore, this study aimed to describe current anesthesia practices across Europe for infants undergoing surgery for NEC. Design: Cross-sectional survey study. Participants: Anesthesiologists working in centers where surgery for NEC is performed across Europe. Measurements: A 46-item questionnaire assessing protocols for anesthesia practice, preoperative care, intraoperative care, postoperative care, and the respondent's opinion on the adequacy of anesthetic care for patients with NEC in their center. Main results: Out of the 173 responding anesthesiologists from 31 countries, approximately a third had a written standard protocol for anesthetic care in infants. Three quarters of the respondents screened all patients with NEC preoperatively, and a third structurally performed preoperative multidisciplinary consultation. For induction of general anesthesia, most respondents opted for intravenous anesthesia (n = 73, 43%) or a combination of intravenous and inhalation anesthesia (n = 57, 33%). For intravenous induction, they mostly used propofol (n = 58, 44%), followed by midazolam (n = 43, 33%) and esketamine (n = 42, 32%). For maintenance of anesthesia, inhalation anesthetic agents were more commonly used (solely: n = 71, 41%; in combination: n = 37, 22%), almost exclusively with sevoflurane. Postoperative analgesics mainly included paracetamol and/or morphine. Sixty percent of the respondents (n = 104) considered their anesthetic care for patients with NEC adequate. Suggestions for further improvement mainly revolved around monitoring, protocols, and collaboration. Conclusions: Anesthesia practice for infants undergoing surgery for NEC was highly variable. Most respondents considered the provided anesthetic care for patients with NEC adequate, but also recognized opportunities for further improvement, especially with regards to monitoring, protocols, and interdisciplinary collaboration.</p

Long-term surgical outcomes of congenital supravalvular aortic stenosis:a systematic review, meta-analysis and microsimulation study

OBJECTIVES: Congenital supravalvular aortic stenosis (SVAS) is a rare form of congenital outflow tract obstruction and long-term outcomes are scarcely reported. This study aims to provide an overview of outcomes after surgical repair for congenital SVAS. METHODS: A systematic review of published literature was conducted, including observational studies reporting long-term clinical outcome (&gt;2 years) after SVAS repair in children or adults considering &gt;20 patients. Early risks, late event rates and time-to-event data were pooled and entered into a microsimulation model to estimate 30-year outcomes. Life expectancy was compared to the age-, sex- and origin-matched general population. RESULTS: Twenty-three publications were included, encompassing a total of 1472 patients (13 125 patient-years; pooled mean follow-up: 9.0 (6.2) years; median follow-up: 6.3 years). Pooled mean age at surgical repair was 4.7 (5.8) years and the most commonly used surgical technique was the single-patch repair (43.6%). Pooled early mortality was 4.2% (95% confidence interval: 3.2-5.5%) and late mortality was 0.61% (95% CI: 0.45-0.83) per patient-year. Based on microsimulation, over a 30-year time horizon, it was estimated that an average patient with SVAS repair (mean age: 4.7 years) had an observed life expectancy that was 90.7% (95% credible interval: 90.0-91.6%) of expected life expectancy in the matched general population. The microsimulation-based 30-year risk of myocardial infarction was 8.1% (95% credible interval: 7.3-9.9%) and reintervention 31.3% (95% credible interval: 29.6-33.4%), of which 27.2% (95% credible interval: 25.8-29.1) due to repair dysfunction. CONCLUSIONS: After surgical repair for SVAS, 30-year survival is lower than the matched-general-population survival and the lifetime risk of reintervention is considerable. Therefore, lifelong monitoring of the cardiovascular system and in particular residual stenosis and coronary obstruction is recommended.</p

Blood and Imaging Biomarkers in the Long-term Follow-up of Bicuspid Aortic Valve Patients

Background: Bicuspid aortic valve (BAV) is a common congenital heart defect. Patients with BAV are at risk for long-term complications such as valve stenosis and regurgitation. This study aimed to investigate sex differences in blood and imaging biomarkers and to describe the long-term prognostic value of blood and echocardiographic biomarkers. Methods:Patients were included from 2 prospective observational cohort studies; they underwent venous blood sampling and transthoracic echocardiography including speckle tracking. Analyzed blood biomarkers were red-cell distribution width (RDW), creatinine, C-reactive protein (CRP), troponin T, N-terminal pro B-type natriuretic peptide (NT-proBNP), and transforming growth factor-beta (TGF-β). Sex differences were analyzed at baseline. Associations between biomarkers and arrhythmia-free and intervention-free survival were determined by Cox regression, adjusted for age and sex. Results:A total of 182 patients with BAV were included: median age 34; interquartile range [IQR]: 23-46 years; 55.5% male. CRP, NT-proBNP, and RDW were higher in women, whereas creatinine, troponin T and TGF-β were higher among men. After a median follow-up time of 6.9 (IQR: 6.5-9.9) years, arrhythmia-free and intervention-free survival was, 81.0% and 73.1%, respectively. NT-proBNP was associated with both arrhythmia-free and intervention-free survival (hazard ratio [HR], 1.94, P = 0.005 and HR, 2.06, P = 0.002, respectively). On echocardiography higher left atrial (LA) size, left ventricular end-diastolic diameter (LVEDD), left ventricular (LV) mass index and E/e’ ratio were associated with lower arrhythmia-free survival, whereas higher LA size, LV mass index, aortic valve peak velocity, and aortic regurgitation were associated with lower intervention-free survival. Conclusions: Differences were observed in blood biomarkers between men and women with BAV. Besides LV systolic parameters, diastolic LV function and NT-proBNP should have a more prominent role as prognostic markers in clinical care.</p

A cross-sectional study on fatigue, anxiety, and symptoms of depression and their relation with medical status in adult patients with Marfan syndrome:Psychological consequences in Marfan syndrome

Marfan syndrome (MFS) is a connective tissue disorder affecting the cardiovascular, ocular, and skeletal system, which may be accompanied by psychological features. This study aimed to determine the prevalence of fatigue, anxiety, and symptoms of depression in MFS patients, and to assess the degree to which sociodemographic and clinical variables are associated with fatigue and psychological aspects. The prevalence of fatigue, anxiety, and symptoms of depression were assessed in two cohorts of MFS patients and compared with healthy controls. The checklist individual strength (CIS), and hospital anxiety and depression scale (HADS) questionnaires were utilized. Medical status was assessed (family history of MFS, aortic root dilatation >40 mm, previous aortic surgery, aortic dissection, chronic pain, skeletal involvement, and scoliosis). Severe fatigue was experienced by 37% of the total MFS cohort (n = 155). MFS patients scored significantly higher on the CIS questionnaire, concerning severe fatigue, as compared with the general Dutch population (p < 0.0001). There were no differences in HADS anxiety or depression scores. In older MFS patients, with a more severe cardiovascular phenotype, chronic pain, and a higher unemployment rate, significantly more symptoms of depression were observed, when compared with the general population (p = 0.027) or compared with younger MFS patients (p = 0.026). Multivariate analysis, showed that anxiety was associated with chronic pain (p = 0.022) and symptoms of depression with unemployment (p = 0.024). MFS patients report significantly more severe fatigue as compared with the general population. Since the cause of fatigue is unclear, more research may be needed. Psychological intervention, for example, cognitive behavioral therapy, may contribute to a reduction in psychological symptoms

Periostin Is Expressed by Pericytes and Is Crucial for Angiogenesis in Glioma

The expression of the matricellular protein periostin has been associated with glioma progression. In previous work we found an association of periostin with glioma angiogenesis. Here, we screen gliomas for POSTN expression and identify the cells that express periostin in human gliomas. In addition, we study the role of periostin in an in vitro model for angiogenesis. The expression of periostin was investigated by RT-PCR and by immunohistochemistry. In addition, we used double labeling and in situ RNA techniques to identify the expre

A Reduction in Time with Electronic Monitoring In Stroke (ARTEMIS): study TA protocol for a randomised multicentre trial

Neuro Imaging Researc