2,602 research outputs found
Hydrogels based on polymerized ionic Liquids as innovative Drug Carriers in controllable and individualized Dosage Forms
Novel Polymerized Ionic Liquids (PILs)-based Hydrogels as Innovative Drug Delivery Systems are presented. The
embedding of drugs in hydrogels enables the “smart” delivery of bioactive molecules from drugs for an oral route of
administration. Therefore, a high mechanical strength as well as a favorable pH-dependent swelling behavior is required
which is shown in this study. A mechanical compression of PILs-based hydrogels up to 98.5% and a high swelling
behavior of poly(VEImBr) hydrogels in a solution with a high pH value is achieved. A significant lower swelling is
achieved in a solution with a lower pH value
Electrode thickness measurement of a Si(Li) detector for the SIXA array
Cathode electrodes of the Si(Li) detector elements of the SIXA X-ray
spectrometer array are formed by gold-palladium alloy contact layers. The
equivalent thickness of gold in one element was measured by observing the
characteristic L-shell X-rays of gold excited by monochromatised synchrotron
radiation with photon energies above the L3 absorption edge of gold. The
results obtained at 4 different photon energies below the L2 edge yield an
average value of 22.4(35) nm which is consistent with the earlier result
extracted from detection efficiency measurements.
PACS: 29.40.Wk; 85.30.De; 07.85.Nc; 95.55.Ka
Keywords: Si(Li) detectors, X-ray spectrometers, X-ray fluorescence, detector
calibration, gold electrodes, synchrotron radiationComment: 10 pages, 4 PostScript figures, uses elsart.sty, submitted to Nucl.
Instrum. Meth.
Sampling binary sparse coding QUBO models using a spiking neuromorphic processor
We consider the problem of computing a sparse binary representation of an
image. To be precise, given an image and an overcomplete, non-orthonormal
basis, we aim to find a sparse binary vector indicating the minimal set of
basis vectors that when added together best reconstruct the given input. We
formulate this problem with an loss on the reconstruction error, and an
(or, equivalently, an ) loss on the binary vector enforcing
sparsity. This yields a so-called Quadratic Unconstrained Binary Optimization
(QUBO) problem, whose solution is generally NP-hard to find. The contribution
of this work is twofold. First, the method of unsupervised and unnormalized
dictionary feature learning for a desired sparsity level to best match the data
is presented. Second, the binary sparse coding problem is then solved on the
Loihi 1 neuromorphic chip by the use of stochastic networks of neurons to
traverse the non-convex energy landscape. The solutions are benchmarked against
the classical heuristic simulated annealing. We demonstrate neuromorphic
computing is suitable for sampling low energy solutions of binary sparse coding
QUBO models, and although Loihi 1 is capable of sampling very sparse solutions
of the QUBO models, there needs to be improvement in the implementation in
order to be competitive with simulated annealing
Institutional investors and stock market efficiency: The case of the January anomaly
In this paper, we investigate the effect of institutional investors on the January stock market anomaly. The Polish and Hungarian pension system reforms and the associated increase in investment activities of pension funds are used as a unique institutional characteristic to provide evidence on the impact of individual versus institutional investors on the January effect. We find robust empirical results that the increase in institutional ownership has reduced the magnitude of an anomalous January effect induced by individual investors' trading behavior
A multi-institutional phase 2 trial of ablative 5-fraction stereotactic magnetic resonance-guided on-table adaptive radiation therapy for borderline resectable and locally advanced pancreatic cancer
PURPOSE: Magnetic resonance (MR) image guidance may facilitate safe ultrahypofractionated radiation dose escalation for inoperable pancreatic ductal adenocarcinoma. We conducted a prospective study evaluating the safety of 5-fraction Stereotactic MR-guided on-table Adaptive Radiation Therapy (SMART) for locally advanced (LAPC) and borderline resectable pancreatic cancer (BRPC).
METHODS AND MATERIALS: Patients with LAPC or BRPC were eligible for this multi-institutional, single-arm, phase 2 trial after ≥3 months of systemic therapy without evidence of distant progression. Fifty gray in 5 fractions was prescribed on a 0.35T MR-guided radiation delivery system. The primary endpoint was acute grade ≥3 gastrointestinal (GI) toxicity definitely attributed to SMART.
RESULTS: One hundred thirty-six patients (LAPC 56.6%, BRPC 43.4%) were enrolled between January 2019 and January 2022. Mean age was 65.7 (36-85) years. Head of pancreas lesions were most common (66.9%). Induction chemotherapy mostly consisted of (modified)FOLFIRINOX (65.4%) or gemcitabine/nab-paclitaxel (16.9%). Mean CA19-9 after induction chemotherapy and before SMART was 71.7 U/mL (0-468). On-table adaptive replanning was performed for 93.1% of all delivered fractions. Median follow-up from diagnosis and SMART was 16.4 and 8.8 months, respectively. The incidence of acute grade ≥3 GI toxicity possibly or probably attributed to SMART was 8.8%, including 2 postoperative deaths that were possibly related to SMART in patients who had surgery. There was no acute grade ≥3 GI toxicity definitely related to SMART. One-year overall survival from SMART was 65.0%.
CONCLUSIONS: The primary endpoint of this study was met with no acute grade ≥3 GI toxicity definitely attributed to ablative 5-fraction SMART. Although it is unclear whether SMART contributed to postoperative toxicity, we recommend caution when pursuing surgery, especially with vascular resection after SMART. Additional follow-up is ongoing to evaluate late toxicity, quality of life, and long-term efficacy
Stereotactic MR-guided on-table adaptive radiation therapy (SMART) for borderline resectable and locally advanced pancreatic cancer: A multi-center, open-label phase 2 study
BACKGROUND AND PURPOSE: Radiation dose escalation may improve local control (LC) and overall survival (OS) in select pancreatic ductal adenocarcinoma (PDAC) patients. We prospectively evaluated the safety and efficacy of ablative stereotactic magnetic resonance (MR)-guided adaptive radiation therapy (SMART) for borderline resectable (BRPC) and locally advanced pancreas cancer (LAPC). The primary endpoint of acute grade ≥ 3 gastrointestinal (GI) toxicity definitely related to SMART was previously published with median follow-up (FU) 8.8 months from SMART. We now present more mature outcomes including OS and late toxicity.
MATERIALS AND METHODS: This prospective, multi-center, single-arm open-label phase 2 trial (NCT03621644) enrolled 136 patients (LAPC 56.6 %; BRPC 43.4 %) after ≥ 3 months of any chemotherapy without distant progression and CA19-9 ≤ 500 U/mL. SMART was delivered on a 0.35 T MR-guided system prescribed to 50 Gy in 5 fractions (biologically effective dose
RESULTS: Mean age was 65.7 years (range, 36-85), induction FOLFIRINOX was common (81.7 %), most received elective coverage (57.4 %), and 34.6 % had surgery after SMART. Median FU was 22.9 months from diagnosis and 14.2 months from SMART, respectively. 2-year OS from diagnosis and SMART were 53.6 % and 40.5 %, respectively. Late grade ≥ 3 toxicity definitely, probably, or possibly attributed to SMART were observed in 0 %, 4.6 %, and 11.5 % patients, respectively.
CONCLUSIONS: Long-term outcomes from the phase 2 SMART trial demonstrate encouraging OS and limited severe toxicity. Additional prospective evaluation of this novel strategy is warranted
Patient specific contouring region of interest for abdominal stereotactic adaptive radiotherapy
Contouring during adaptive radiotherapy (ART) can be a time-consuming process. This study describes the generation of patient specific contouring regions of interest (CRoI) for evaluating the high dose fall-off in stereotactic abdominal ART. An empirical equation was derived to determine the radius of a cylindrical patient specific CRoIs. These CRoIs were applied to 60 patients and their adaptive fractions (301 unique treatment plans). Out of the 301 unique treatment plans, 284 (94%) treatment plans contained the high dose fall-off within the CRoI. There was an expected predicted average timesaving of 2.9-min-per case. Patient specific CRoIs improves the efficiency of ART
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