The development of orthogonal acceleration time-of-flight (oa-tof) technology is driven forward due to higher mass accuracy and resolving power than conventional linear/reflectron tof instruments. ...This is achieved with a more accurate definition of starting energies and coordinates of ions by spatial separation of ion generation and orthogonal ion extraction. Consequently, the ability to cover the whole mass spectral range without scanning is not given anymore. Therefore, continuous ion sources are favored for ensuring high duty cycles and thus high temporal resolution. For pulsed ion sources, high repetition rates are mandatory for covering large
m
/
z
ranges without losing their high temporal resolution. We have combined an oa-tof with deuterium lamp single-photon ionization (SPI) as a continuous ion source together with a pulsed 2000 Hz excimer (KrF) laser for resonance enhanced multi-photon ionization (REMPI). These two ionization techniques can be used simultaneously. To the best of our knowledge, this system is the first of its kind in combining a vacuum pulsed ionization source with an oa-tof instrument without any other ion storage hardware. The combination of a soft broadband ionization for organics (SPI) in combination with a very sensitive and selective soft ionization (REMPI) can be used for covering the whole mass range or in targeted on-line monitoring cases one or several smaller mass ranges. To demonstrate the simultaneous SPI/REMPI-oa-tof technique, two applicative areas are explored: on-line monitoring of coffee roast gas emissions and e-cigarette vapor. The complementary information from SPI and REMPI signals are combined in a way to exploit the advantages of both ionization types. In a further development step, a second data acquisition card is built into the system. This modification allows the independent storage of data from both ionization methods without mixing. For demonstration, a third example with a GC measurement is provided. The last example shows the possibility of modified sensitivities for different mass regions in REMPI data acquisition without affecting the SPI channel. The newly developed system shows high robustness in terms of measurements in real industrial environments. The simultaneous measurement technique provides a higher density of information in a single measurement, saving time and resources.
New instrumental development for robust process monitoring with two soft ionization methods working in parallel.
A systematic review of transition literature was conducted on 743 articles published in 22 special education journals from 1990 to 2015. Demographic data and topics of transition-related articles ...were coded to identify the trends in transition literature. Results found only 4.1% of articles in those journals focused on transition. Student participants were primarily White males with a specific learning disability or intellectual disability. Key topics of transition (e.g., self-determination, transition planning) were supported by several studies in the literature. Yet, crucial topics (e.g., transportation skills, interagency collaboration) contained little research support. A summary of the current trends in transition research and implications for future research are discussed.
Increased amino acid transport in brain tumours is used for diagnostic purposes. It has been shown that the α-emitting radionuclide astatine-211 labeled to L-phenylalanine is taken up by glioblastoma ...cells. We here tested, if systemic treatment with 4-211Atastatine-phenylalanine (At-Phe) has a beneficial effect on survival of rats with intracranial glioblastoma.
The rat glioblastoma cell line BT4Ca was implanted into the prefrontal cortex of female BDIX rats by stereotaxic microinjection (10,000 cells/3 µl; n = 83). 3 days after implantation At-Phe or phosphate buffered saline were injected intravenously. A third group was treated twice, i.e., on day 3 and 10. Health condition was assessed each day by using a score system. Rats were sacrificed on days 6, 10, 13 and 17 after implantation, or when showing premortal health condition to measure tumour volume and necrosis. The proliferation index (PI) was assessed after immunohistochemical staining of Ki-67.
Survival time of rats treated twice with At-Phe was significantly prolonged. Additionally, both At-Phe-treated groups remained significantly longer in a better health condition. Rats with poor health status had larger tumours than rats with fair health condition. Overall, irrespective of treatment the PI was reduced in rats with poor health condition. Necrosis was larger in rats treated twice with At-Phe.
Intravenous treatment with At-Phe enhanced survival time of rats with intracranial glioblastomas and improved health condition. These results encourage studies using local treatment of intracranial glioblastoma with At-Phe, either by repeated local injection or by intracavital application after tumour resection.
Purpose
68
GaTrishydroxypyridinone (THP)–prostate-specific membrane antigen (PSMA) is a novel tracer that can be labeled in one step by cold reconstitution of a kit with unprocessed generator ...eluate, targeting PSMA
via
the lysine-urea-glutamate (KuE) motif. The aim of this study was to evaluate the human imaging characteristics of
68
GaTHP-PSMA.
Procedures
68
GaTHP-PSMA positron emission tomography (PET)/x-ray computed tomography (CT) was performed in 25 patients with biochemical recurrence after radical prostatectomy for prostate cancer. Urinary and biliary excretion and tumor lesion uptake were quantified using standardized uptake values (SUVs). Imaging characteristics were assessed in terms of non-target organ uptake, background activity, target-to-background ratios (TBRs) of tumor lesions, and frequency of bladder halo artifacts. Findings were compared to a matched cohort of 25 patients undergoing PET/CT with the established agent
68
GaPSMA I&T.
Results
Physiologic uptake of
68
GaTHP-PSMA was significantly lower in salivary glands (
P
< 0.0001), liver (
P
< 0.0001), spleen (
P
< 0.0001), and kidneys (
P
< 0.0001) than with
68
GaPSMA I&T. While biliary tracer excretion of
68
GaTHP-PSMA was negligible, urinary tracer excretion of
68
GaTHP-PSMA was fast, and significantly higher than for
68
GaPSMA I&T, contributing to a higher frequency of bladder artifacts. Malignant lesion uptake of
68
GaTHP-PSMA assessed as either SUV or TBR was significantly lower than with
68
GaPSMA I&T.
Conclusion
68
GaTHP-PSMA yields suitable
in vivo
uptake characteristics. The simplified synthesis method for
68
GaTHP-PSMA may facilitate wider application and higher patient throughput with PSMA imaging. However, direct intraindividual comparison studies are needed to assess the relative performance of
68
GaTHP-PSMA
vs
other PSMA ligands in terms of clinical detection rate and image quality.
A novel small enrichment unit based on the trap and thermal desorption technique was used in combination with a portable electronic nose. A better detection limit is achieved due to the trapping ...procedure during sampling. A better selectivity is achieved by means of degradation of disturbing compounds from the analysis. Especially, the extraction of ethanol is important for the analysis of alcoholic beverages. Influences to water changes are minimized. Selected examples with use of this enrichment unit show the possibilities for enhanced measurement with known and new applications.
Hydraulic tomography (HT) is a new technology that images the hydraulic heterogeneity of the subsurface. Unlike steady state hydraulic tomography (SSHT), which provides a hydraulic conductivity (K) ...tomogram, transient hydraulic tomography (THT) provides reliable tomograms of both K and specific storage (S(s)). Effective as it may be, THT is a computationally demanding technique. To ease the computational burden, a HT which utilizes zeroth and first temporal moments of transient drawdown recovery data (HT-m) has been developed by Zhu and Yeh (2006). This procedure simplifies the governing equation from a single parabolic equation to two Poisson's equations for the zeroth moment and characteristic time defined as the ratio between the first and zeroth moments. The approach was previously tested using synthetic simulations. The numerical experiments tested the feasibility of HT-m under ideal conditions, where measurements and model are assumed to be free of error. In this paper, we further evaluate the performance of HT-m using cross-hole pumping tests conducted in a heterogeneous, synthetic aquifer constructed in a laboratory sandbox in more realistic situations, where the data used in the inversion are not free of experimental errors. Unlike field tests, the laboratory tests were conducted in a synthetic aquifer created with a prescribed heterogeneity pattern and all forcing functions (initial and boundary conditions and source-sink terms) controlled. Results from the HT-m approach were compared to those from THT previously conducted by Liu et al. (2007). Our results show that the estimation of the K tomogram using the HT-m approach is reasonable, but the estimation of the S s tomogram is unreliable in comparison to the THT approach.
Purpose
68
GaTris(hydroxypyridinone)(THP)-PSMA is a novel radiopharmaceutical for one-step kit-based radiolabelling, based on direct chelation of
68
Ga
3+
at low concentration, room temperature and ...over a wide pH range, using direct elution from a
68
Ge/
68
Ga-generator. We evaluated the clinical detection rates of
68
GaTHP-PSMA PET/CT in patients with biochemically recurrent prostate cancer after prostatectomy.
Methods
Consecutive patients (n=99) referred for evaluation of biochemical relapse of prostate cancer by
68
GaTHP-PSMA PET/CT were analyzed retrospectively. Patients underwent a standard whole-body PET/CT (1 h p.i.), followed by delayed (3 h p.i.) imaging of the abdomen. PSA-stratified cohorts of positive PET/CT results, standardized uptake values (SUVs) and target-to-background ratios (TBRs) were analyzed, and compared between standard and delayed imaging.
Results
At least one lesion suggestive of recurrent or metastatic prostate cancer was identified on PET images in 52 patients (52.5%). Detection rates of
68
GaTHP-PSMA PET/CT increased with increasing PSA level: 94.1% for a PSA value of ≥10 ng/mL, 77.3% for a PSA value of 2 to <10 ng/mL, 54.5% for a PSA value of 1 to <2 ng/mL, 14.3% for a PSA value of 0.5 to <1 ng/mL, 20.0% for a PSA value of >0.2 to <0.5, and 22.2% for a PSA value of 0.01 to 0.2 ng/mL.
68
GaTHP-PSMA uptake (SUVs) in metastases decreased over time, whereas TBRs improved. Delayed imaging at 3 h p.i. exclusively identified pathologic findings in 2% of
68
GaTHP-PSMA PET/CT scans. Detection rate was higher in patients with a Gleason score ≥8 (
P
=0.02) and in patients receiving androgen deprivation therapy (
P
=0.003).
Conclusions
In this study,
68
GaTHP-PSMA PET/CT showed suitable detection rates in patients with biochemical recurrence of prostate cancer and PSA levels ≥ 2 ng /mL. Detections rates were lower than in previous studies evaluating other PSMA ligands, though prospective direct radiotracer comparison studies are mandatory particularly in patients with low PSA levels to evaluate the relative performance of different PSMA ligands.
The knowledge of the physiological aspects of Caatinga’s vegetal species is extremely important for preserving this biome, which suffers with human impacts, mainly to select propagation methods. ...Erythrina velutina is a Brazilian tree, generally found in Caatinga, with medical and forestry potential. The objective of this paper was to determine the best soaking period in gibberellin solution to achieve the highest germination and to evaluate the internal anatomy by digital microtomography of E. velutina seeds. The design was completely randomized and consisted of eight treatments: 1, 3, 6, 12, 24 and 48 h of soaking, scarified seeds and the control with no-scarified seeds. Digital microtomography was efficient in describing the anatomy of the seeds and distinguishing their tissues. There was no significant difference between the treatments at different soaking times, as the gibberellic acid did not influence the germination; only the control presented a lower germination percentage, differing from the other treatments. The study presents evidence that E. velutina seeds do not require the exogenous use of gibberellic acid, but only the scarification process. In addition, the use of digital microtomography can be useful in understanding the anatomy of seeds, especially forest species, which can contribute to the future studies of other plant species.
Ion mobility spectrometers can be divided by their principle of ion separation. For example, classical drift tube time-of-flight Ion Mobility Spectrometers (IMS) separate ions by the absolute value ...of their low field ion mobility; Field Asymmetric Ion Mobility Spectrometers (FAIMS) separate ions by the field dependence of their ion mobility. However, the low field mobilities and the field dependence of the mobility vary only within a limited range for different ions, leading to a limited peak capacity of stand-alone drift tube IMS and FAIMS. Combining both types leads to orthogonal data and thus enhances the selectivity in comparison with stand-alone devices. In this work, a new approach of enhancing the separation power of a classical drift tube IMS by integrating a field asymmetric waveform ion separation region in longitudinal direction into the drift tube is discussed. This additional separation region is realized by superimposing the constant drift field of a drift tube IMS with an asymmetric parallel AC field using two additional grids inside the drift tube. Since the ions are exposed alternately to high field and low field strengths on their way through the additional separation region, the resulting drift time is affected. Hence, two ion species having the same low-field mobility, but showing a different field dependence of the mobility have different drift times in the enhanced IMS. In order to analyze the ion movement inside such a modified ion mobility spectrometer, the finite element method (FEM) software
Comsol Multiphysics
is used. Therefore, an existing drift tube IMS model which perfectly agrees with experimental results and considers field inhomogenieties, diffusion, Coulomb repulsion and ion losses at metallic surfaces, is expanded in order to simulate the ion movement in AC fields. This enhanced model provides visualization of the location and shape of the ion cloud during DC/AC operation. Particular attention is given to the increased broadening of the ion cloud due to field inhomogenieties in the additional AC field. Furthermore, ion losses inside the drift tube caused by the AC field and the additional grids are considered. In this work, simulations are used to theoretically investigate our new separation approach to give a first impression of the possible analytical performance.
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