Fibre laser hydrophones for cosmic ray particle detection

The detection of ultra high energetic cosmic neutrinos provides a unique means to search for extragalactic sources that accelerate particles to extreme energies. It allows to study the neutrino component of the GZK cut-off in the cosmic ray energy spectrum and the search for neutrinos beyond this limit. Due to low expected flux and small interaction cross-section of neutrinos with matter large experimental set-ups are needed to conduct this type of research. Acoustic detection of cosmic rays may provide a means for the detection of ultra-high energetic neutrinos. Using relative low absorption of sound in water, large experimental set-ups in the deep sea are possible that are able to detect these most rare events, but it requires highly sensitive hydrophones as the thermo-acoustic pulse originating from a particle shower in water has a typical amplitude as low as a mPa. It has been shown in characterisation measurements that the fibre optic hydrophone technology as designed and realised at TNO provides the required sensitivity. Noise measurements and pulse reconstruction have been conducted that show that the hydrophone is suited as a particle detector.Comment: Submitted to the proceedings of "13th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD13)

Surgical intervention for hydrocephalus in infancy; etiology, age and treatment data in a Dutch cohort

Contains fulltext : 217415.pdf (Publisher’s version ) (Open Access

Is surgical subspecialization associated with hand grip strength and manual dexterity?:A cross-sectional study

BACKGROUND: The aim of this study was to compare hand grip strength (HGS) and manual dexterity of academic, subspecialized surgeons. METHODS: A single-center cross-sectional study was performed among 61 surgeons. HGS was analysed with a hand dynamometer and manual dexterity was extensively analysed with a Purdue Pegboard Test. Correlations between HGS and manual dexterity and specific characteristics of the surgeons were analysed using Pearson's correlation coefficient (r). RESULTS: HGS and manual dexterity were comparable between surgeons from different specialities. HGS was positively correlated with male gender (r = 0.59, p < 0.001) and hand glove size (r = 0.61, p < 0.001), whereas manual dexterity was negatively correlated with male gender (r = −0.35, p = 0.006), age (r = −0.39, = 0.002), and hand glove size (r = −0.46, p < 0.001). CONCLUSIONS: Surgical subspecialization was not correlated with HGS or manual dexterity. Male surgeons have greater HGS, whereas female surgeons have better manual dexterity. Manual dexterity is also correlated with age, showing better scores for younger surgeons

A prospective cohort study evaluating screening and assessment of six modifiable risk factors in HPB cancer patients and compliance to recommended prehabilitation interventions

INTRODUCTION: Despite improvements in perioperative care, major abdominal surgery continues to be associated with significant perioperative morbidity. Accurate preoperative risk stratification and optimisation (prehabilitation) are necessary to reduce perioperative morbidity. This study evaluated the screening and assessment of modifiable risk factors amendable for prehabilitation interventions and measured the patient compliance rate with recommended interventions.METHOD: Between May 2019 and January 2020, patients referred to our hospital for HPB surgery were screened and assessed on six modifiable preoperative risk factors. The risk factors and screening tools used, with cutoff values, included (i) low physical fitness (a 6-min walk test &lt; 82% of patient's calculated norm and/or patient's activity level not meeting the global recommendations on physical activity for health). Patients who were unfit based on the screening were assessed with a cardiopulmonary exercise test (anaerobic threshold ≤ 11 mL/kg/min); (ii) malnutrition (patient-generated subjective global assessment ≥ 4); (iii) iron-deficiency anaemia (haemoglobin &lt; 12 g/dL for women, &lt; 13 g/dL for men and transferrin saturation ≤ 20%); (iv) frailty (Groningen frailty indicator/Robinson frailty score ≥ 4); (v) substance use (smoking and alcohol use of &gt; 5 units per week) and (vi) low psychological resilience (Hospital Anxiety and Depression Scale ≥ 8). Patients had a consultation with the surgeon on the same day as their screening. High-risk patients were referred for necessary interventions.RESULTS: One hundred consecutive patients were screened at our prehabilitation outpatient clinic. The prevalence of high-risk patients per risk factor was 64% for low physical fitness, 42% for malnutrition, 32% for anaemia (in 47% due to iron deficiency), 22% for frailty, 12% for smoking, 18% for alcohol use and 21% for low psychological resilience. Of the 77 patients who were eventually scheduled for surgery, 53 (68.8%) needed at least one intervention, of whom 28 (52.8%) complied with 100% of the necessary interventions. The median (IQR) number of interventions needed in the 77 patients was 1.0 (0-2).CONCLUSION: It is feasible to screen and assess all patients referred for HPB cancer surgery for six modifiable risk factors. Most of the patients had at least one risk factor that could be optimised. However, compliance with the suggested interventions remains challenging.</p

Enhancement of drug oxidation and conjugation by carcinogens in different rat tissues

OBJECTIVE After endoscopic third ventriculostomy (ETV), some patients develop recurrent symptoms of hydrocephalus. The optimal treatment for these patients is not clear: repeat ETV (re-ETV) or CSF shunting. The goals of the study were to assess the effectiveness of re-ETV relative to initial ETV in pediatric patients and validate the ETV success score (ETVSS) for re-ETV. METHODS Retrospective data of 624 ETV and 93 re-ETV procedures were collected from 6 neurosurgical centers in the Netherlands (1998-2015). Multivariable Cox proportional hazards modeling was used to provide an adjusted estimate of the hazard ratio for re-ETV failure relative to ETV failure. The correlation coefficient between ETVSS and the chance of re-ETV success was calculated using Kendall's tau coefficient. Model discrimination was quantified using the c-statistic. The effects of intraoperative findings and management on re-ETV success were also analyzed. RESULTS The hazard ratio for re-ETV failure relative to ETV failure was 1.23 (95% CI 0.90-1.69; p = 0.20). At 6 months, the success rates for both ETV and re-ETV were 68%. ETVSS was significantly related to the chances of re-ETV success (tau = 0.37; 95% bias corrected and accelerated CI 0.21-0.52; p < 0.001). The c-statistic was 0.74 (95% CI 0.64-0.85). The presence of prepontine arachnoid membranes and use of an external ventricular drain (EVD) were negatively associated with treatment success, with ORs of 4.0 (95% CI 1.5-10.5) and 9.7 (95% CI 3.4-27.8), respectively. CONCLUSIONS Re-ETV seems to be as safe and effective as initial ETV. ETVSS adequately predicts the chance of successful re-ETV. The presence of prepontine arachnoid membranes and the use of EVD negatively influence the chance of success

Successful Thrombectomy via a Surgically Reopened Umbilical Vein for Extended Portal Vein Thrombosis Caused by Portal Vein Embolization prior to Extended Liver Resection

Selective portal vein embolization (PVE) before extended liver surgery is an accepted method to stimulate growth of the future liver remnant. Portal vein thrombosis (PVT) of the main stem and the non-targeted branches to the future liver remnant is a rare but major complication of PVE, requiring immediate revascularization. Without revascularization, curative liver surgery is not possible, resulting in a potentially life-threatening situation. We here present a new surgical technique to revascularize the portal vein after PVT by combining a surgical thrombectomy with catheter-based thrombolysis via the surgically reopened umbilical vein. This technique was successfully applied in a patient who developed thrombosis of the portal vein main stem, as well as the left portal vein and its branches to the left lateral segments after selective right-sided PVE in preparation for an extended right hemihepatectomy. The advantage of this technique is the avoidance of an exploration of hepatoduodenal ligament and a venotomy of the portal vein. The minimal surgical trauma facilitates additional intravascular thrombolytic therapy as well as the future right extended hemihepatectomy. We recommend this technique in patients with extensive PVT in which percutaneous less invasive therapies have been proven unsuccessful