Resolving Power of Visible to Near-Infrared Hybrid β\beta-Ta/NbTiN Kinetic Inductance Detectors

Kinetic Inductance Detectors (KIDs) are superconducting energy-resolving detectors, sensitive to single photons from the near-infrared to ultraviolet. We study a hybrid KID design consisting of a beta phase tantalum ($\beta$-Ta) inductor and a NbTiN interdigitated capacitor (IDC). The devices show an average intrinsic quality factor $Q_i$ of 4.3$\times10^5$ $\pm$ 1.3 $\times10^5$. To increase the power captured by the light sensitive inductor, we 3D-print an array of 150$\times$150 $\mu$m resin micro lenses on the backside of the sapphire substrate. The shape deviation between design and printed lenses is smaller than 1$\mu$m, and the alignment accuracy of this process is $\delta_x = +5.8 \pm 0.5$ $\mu$m and $\delta_y = +8.3 \pm 3.3$ $\mu$m. We measure a resolving power for 1545-402 nm that is limited to 4.9 by saturation in the KID's phase response. We can model the saturation in the phase response with the evolution of the number of quasiparticles generated by a photon event. An alternative coordinate system that has a linear response raises the resolving power to 5.9 at 402 nm. We verify the measured resolving power with a two-line measurement using a laser source and a monochromator. We discuss several improvements that can be made to the devices on a route towards KID arrays with high resolving powers.Comment: 11 pages, 9 Figues, Journal Pape

Monolithically fabricated flexible graphene-based active implant

Treatment of diseases, illnesses or disorders are always sought without any undesired side-effects and complications. Neurological disorders, such as Epilepsy and Parkinson’s, are currently treated using pharmaceuticals. However, drugs have a low specificity and lose their effectiveness after several years. In addition, prolonged drug usage often leaves patients with many side-effects and complications. Development in neuroscience indicate the treatment of such neurological disorders via neuro-stimulation. Currently, research in understanding the mechanisms behind neuronal stimulation is carried out by research institutes all around the globe. There are three modes for neuronal stimulation, electrical, optical and lastly the use of ultrasonic waves. As optogenetics provides a more specific technique in neuronal stimulation and electrical recording can provide high spatial resolution data, it is sought to combine this two modes.This work reports the development of a monolithically fabricated active implant, with optogenetic compatibility using transfer-free graphene electrodes. To achieve this desired goal, a microfabrication process is developed, which is reproducible and scalable with modern day microfabrication technology. In order to be compatible with optogenetics, graphene electrodes are used, as these are transparent and allow for neuronal stimulation using light. The graphene electrodes are grown on a pre-defined molybdenum catalyst, allowing for a transfer-free chemical vapor depostion (CVD) of graphene. Microelectrode-arrays (MEAs) are developed, using graphene electrodes, that include different sized electrodes and different amount of electrodes. The amount being constrained by the available space on the cortex of a mouse.The aim of this work was to be able to control or read out these MEAs using electronics developed alongside the electrodes. As graphene is grown at a temperature above the melting point of aluminium, conventional CMOS technology can not be used in combination with graphene electrodes. The process developed, did not include any materials which would be damaged during the graphene growth. The metal gate is replaced by a polysilicon gate and the metal interconnects connecting the active devices and the MEAs are defined after the growth of graphene. Resulting in an active implant which is monolithically fabricated in combination with a transfer-free graphene process.Monolithically fabricating an active graphene based implant, comes with complications. Delamination of the passivisation layer occurred whilst trying to open contact openings to and from the active devices. This was resolved using a more appropriate chemical etchant.A fully monolithically fabricated active graphene-based implant was obtained. Electrical measurements showed that the active devices did not behave as expected. Revisiting simulations, it was established that there was leakage of dopants from the gate to the channel. This results in the NMOS devices to be always on and the PMOS devices to have a higher threshold voltage.However, this particular wafer, had many high temperature steps after the doping of the polysilicon. Reduction of these high temperature steps result in less doping getting into the channel. Alternatively, a thicker gate oxide can be used, to serve as a more robust barrier. A last proposed solution is the reduction of the doping concentration and doping energy of the polysilicon, which would result in less dopant being near the gate oxide interface and thus less dopant leaking into the channel.There are wafers included in this work with less high temperature steps. However, due to time limitation it was not possible to finish production of these wafer in order to confirm it experimentally. Nevertheless, it is believed that with minor adjustments, this research project is a viable foundation for active graphene based implants and structures.Biomedical Engineerin

Portal Vein Hemodialysis-Tunneled Catheter: A Case Report in a Pediatric Patient with Extensive Systemic Venous Thrombosis

We report a case of an 11-year-old child with end-stage renal disease and extensive systemic venous thrombosis including the inferior and superior vena cava. Transhepatic portal vein hemodialysis tunneled catheter was inserted after exhausting all other possible venous access through internal jugular, subclavian, femoral, and hepatic veins

Role of prostatic artery embolization in management of symptomatic benign prostatic hyperplasia

AbstractObjectivesTo assess the feasibility and efficacy of prostatic artery embolization in relieving symptoms of benign prostatic hyperplasia.Materials and methodsIn a prospective study 28 patients with symptomatic benign prostatic hyperplasia were presented for prostatic artery embolization between June 2012 and June 2014. Patients age was 48–85years with mean age 68.5years±10.6SD. International Prostate Symptoms Score (IPSS) before intervention measured 20–35 with mean score 26.3±6.8SD. Prostatic volume before intervention ranged between 48 and 166cc3 with mean of 82.6±11.2SD.ResultsTechnical success was achieved in all cases (100%). All patients were followed for 6months after the procedure. IPSS improved at 6months in all patients with post embolization mean of 12.2±3.4SD with significant P value of 0.0006. Mean post-procedure prostatic volume at 6months was 49.8cc3±16.9SD with 39.7% mean volume reduction. No major complications were recorded. We achieved clinical success in 27 patients (96.4%) with only one non responding patient (3.6%).ConclusionProstatic artery embolization is a feasible technique and preliminary short-term results show promising high technical and clinical success rates in symptomatic patients with benign prostatic hyperplasia

Percutaneous Endoscopic Gastrostomy Large-Bore Tube Application without the Use of Endoscope: Single-Center Experience on 86 Neurologically Compromised Patients

Context: Percutaneous placement of gastrostomy tube has replaced surgical placement as the most accepted method of gastrostomy tube insertion. It can be done by an alternative nonendoscopic fluoroscopy-guided technique that combines the advantages of fluoroscopic guidance and the pull technique. Aims: This study aimed to describe a percutaneous fluoroscopy-guided technique for applying mushroom-retained large-bore gastrostomy advanced through the nose without endoscopy. Settings and Design: This retrospective study was conducted at the Interventional Radiology Unit, Ain Shams University Hospitals, Cairo, Egypt. Subjects and Methods: Between January 2015 and November 2017, 86 neurologically compromised patients underwent placement of 24F mushroom gastrostomy tubes. There were 55 males and 31 females, with the mean age of 61 years (58–87 years). Technical success and procedural complications were assessed. Follow-up data were collected retrospectively by reviewing the medical records at the neurology clinic to evaluate tube function and monitor complications. Results: Technical success rate was 100%. Procedure time varied between 10 and 13 min. No major procedure-related complications occurred. Twenty-two patients (25.5%) died during the study period with no procedure-related deaths. Nearly 34.8% of the patients (30/86 patients) could not be followed up due to loss of contact. Follow-up time ranged between 200 and 230 days in the remaining 34 patients with no evidence of tube dysfunction. Conclusions: Fluoroscopy-guided percutaneous placement of large-bore pull gastrostomy tubes inserted via nasal route showed a high rate of technical success and long-term patency with low risk of complications

Extracardiac conduit adequacy along the respiratory cycle in adolescent Fontan patients

OBJECTIVES: Adequacy of 16-20mm extracardiac conduits for adolescent Fontan patients remains unknown. This study aims to evaluate conduit adequacy using the inferior vena cava (IVC)-conduit velocity mismatch factor along the respiratory cycle. METHODS: Real-time 2D flow MRI was prospectively acquired in 50 extracardiac (16-20mm conduits) Fontan patients (mean age 16.9 ± 4.5 years) at the subhepatic IVC, conduit and superior vena cava. Hepatic venous flow was determined by subtracting IVC flow from conduit flow. The cross-sectional area (CSA) was reported for each vessel. Mean flow and velocity was calculated during the average respiratory cycle, inspiration and expiration. The IVC-conduit velocity mismatch factor was determined as follows: Vconduit/VIVC, where V is the mean velocity. RESULTS: Median conduit CSA and IVC CSA were 221 mm2 (Q1-Q3 201-255) and 244 mm2 (Q1-Q3 203-265), respectively. From the IVC towards the conduit, flow rates increased significantly due to the entry of hepatic venous flow (IVC 1.9, Q1-Q3 1.5-2.2) versus conduit (3.3, Q1-Q3 2.5-4.0 l/min, P < 0.001). Consequently, mean velocity significantly increased (IVC 12 (Q1-Q3 11-14 cm/s) versus conduit 25 (Q1-Q3 17-31 cm/s), P < 0.001), resulting in a median IVC-conduit velocity mismatch of 1.8 (Q1-Q3 1.5-2.4), further augmenting during inspiration (median 2.3, Q1-Q3 1.8-3.0). IVC-conduit mismatch was inversely related to measured conduit size and positively correlated with conduit flow. The normalized IVC-conduit velocity mismatch factor during expiration and the entire respiratory cycle correlated with peak VO2 (r = -0.37, P = 0.014 and r = -0.31, P = 0.04, respectively). CONCLUSIONS: Important blood flow accelerations are observed from the IVC towards the conduit in adolescent Fontan patients, which is related to peak VO2. This study, therefore, raises concerns that implanted 16-20mm conduits have become undersized for older Fontan patients and future studies should clarify its effect on long-term outcome. ChemE/Transport Phenomen

Extracardiac conduit adequacy along the respiratory cycle in adolescent Fontan patients

OBJECTIVES: Adequacy of 16-20mm extracardiac conduits for adolescent Fontan patients remains unknown. This study aims to evaluate conduit adequacy using the inferior vena cava (IVC)-conduit velocity mismatch factor along the respiratory cycle. METHODS: Real-time 2D flow MRI was prospectively acquired in 50 extracardiac (16-20mm conduits) Fontan patients (mean age 16.9 ± 4.5 years) at the subhepatic IVC, conduit and superior vena cava. Hepatic venous flow was determined by subtracting IVC flow from conduit flow. The cross-sectional area (CSA) was reported for each vessel. Mean flow and velocity was calculated during the average respiratory cycle, inspiration and expiration. The IVC-conduit velocity mismatch factor was determined as follows: Vconduit/VIVC, where V is the mean velocity. RESULTS: Median conduit CSA and IVC CSA were 221 mm2 (Q1-Q3 201-255) and 244 mm2 (Q1-Q3 203-265), respectively. From the IVC towards the conduit, flow rates increased significantly due to the entry of hepatic venous flow (IVC 1.9, Q1-Q3 1.5-2.2) versus conduit (3.3, Q1-Q3 2.5-4.0 l/min, P < 0.001). Consequently, mean velocity significantly increased (IVC 12 (Q1-Q3 11-14 cm/s) versus conduit 25 (Q1-Q3 17-31 cm/s), P < 0.001), resulting in a median IVC-conduit velocity mismatch of 1.8 (Q1-Q3 1.5-2.4), further augmenting during inspiration (median 2.3, Q1-Q3 1.8-3.0). IVC-conduit mismatch was inversely related to measured conduit size and positively correlated with conduit flow. The normalized IVC-conduit velocity mismatch factor during expiration and the entire respiratory cycle correlated with peak VO2 (r = -0.37, P = 0.014 and r = -0.31, P = 0.04, respectively). CONCLUSIONS: Important blood flow accelerations are observed from the IVC towards the conduit in adolescent Fontan patients, which is related to peak VO2. This study, therefore, raises concerns that implanted 16-20mm conduits have become undersized for older Fontan patients and future studies should clarify its effect on long-term outcome