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A formal Gender Dysphoria classification— as outlined in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders— is a prerequisite for the reimbursement of both gender‐affirming medical care and transgender mental health care in the Netherlands. Gender Dysphoria and its conceptual precursors have always been moving targets: moving due to research, policy, care practices and activism both within and outside of medicine. This raises the question of what Gender Dysphoria is exactly. To elucidate this question, we turn to the people who use the concept in clinical practice to come to a diagnosis and treatment indication: mental health professionals working in gender‐affirming medical care and transgender mental health care. Using a material semiotics approach, we reflect upon how Gender Dysphoria is done in clinical practice. Based on an analysis of seventeen practice‐based interviews with clinicians as well as an examination of clinical guidelines and texts, we describe four modes in which Gender Dysphoria is ordered. These modes of ordering illustrate that Gender Dysphoria is not one, but multiple. We illustrate how in the mode of isolating, Gender Dysphoria is something which is carefully isolated from mental disorders, while in the modes doing the future and narrating, Gender Dysphoria is done as a continuous and predictable object of care. Such orderings of Gender Dysphoria potentially conflict with a fourth mode of ordering: the doing of diversity in transgender health care. The study's findings provide empirical insights into how transgender health care is currently done in The Netherlands and provide a foundation on which ethical debates on what good transgender health care should entail. [ABSTRACT FROM AUTHOR]

Context: Inhibition of the neonatal fragment crystallizable receptor (FcRn) reduces pathogenic thyrotropin receptor antibodies (TSH-R-Ab) that drive pathology in thyroid eye disease (TED). Objective: We report the first clinical studies of an FcRn inhibitor, batoclimab, in TED. Design: Proof-of-concept (POC) and randomized, double-blind placebo-controlled trials. Setting: Multicenter. Participants: Patients with moderate-to-severe, active TED. Intervention: In the POC trial, patients received weekly subcutaneous injections of batoclimab 680 mg for 2 weeks, followed by 340 mg for 4 weeks. In the double-blind trial, patients were randomized 2:2:1:2 to weekly batoclimab (680 mg, 340 mg, 255 mg) or placebo for 12 weeks. Main Outcome: Change from baseline in serum anti-TSH-R-Ab and total IgG (POC); 12-week proptosis response (randomized trial). Results: The randomized trial was terminated because of an unanticipated increase in serum cholesterol; therefore, data from 65 of the planned 77 patients were analyzed. Both trials showed marked decreases in pathogenic anti-TSH-R-Ab and total IgG serum levels (P< .001) with batoclimab. In the randomized trial, there was no statistically significant difference with batoclimab vs placebo in proptosis response at 12 weeks, although significant differences were observed at several earlier timepoints. In addition, orbital muscle volume decreased (P < .03) at 12 weeks, whereas quality of life (appearance subscale) improved (P< .03) at 19 weeks in the 680-mg group. Batoclimab was generally well tolerated, with albumin reductions and increases in lipids that reversed upon discontinuation. Conclusions: These results provide insight into the efficacy and safety of batoclimab and support its further investigation as a potential therapy for TED. [ABSTRACT FROM AUTHOR]

Background: In gender-affirming medical care (GAMC), ethical challenges in decision-making are ubiquitous. These challenges are becoming more pressing due to exponentially increasing referrals, politico-legal contestation, and divergent normative views regarding decisional roles and models. Little is known, however, about what ethical challenges related to decision-making healthcare professionals (HCPs) themselves face in their daily work in GAMC and how these relate to, for example, the subjective nature of Gender Incongruence (GI), the multidisciplinary character of GAMC and the role HCPs play in assessing GI and eligibility for interventions. Given the relevance and urgency of these questions, we conducted a qualitative study among HCPs providing GAMC to transgender adults in the Netherlands. Methods: In this qualitative research, we conducted 11 semi-structured interviews between May 2020 and February 2021 with HCPs (six mental health professionals, two HCPs in endocrinology, two in plastic surgery, and one in nursing) working in two distinct GAMC settings. We purposively sampled for professional background and years of experience in GAMC. We analyzed our interview data using thematic analysis. As some respondents were more inclined to speak about what should or ought to be done to arrive at good or right decision-making, we identified both ethical challenges and norms. Furthermore, in our analysis, we differentiated between respondents' explicit and implicit ethical challenges and norms and ascertained the specific context in which these challenges emerged. Results: Respondents' ethical challenges and norms centered on (1) dividing and defining decisional roles and bounds, (2) negotiating decision-making in a (multidisciplinary) team, and (3) navigating various decision-making temporalities. These themes arose in the context of uncertainties regarding (1) GAMC's guidelines, evidence, and outcomes, as well as (2) the boundaries and assessment of GI. Conclusions: This interview study provides detailed empirical insight into both the explicit and implicit ethical challenges that HCPs experience and their ethical norms regarding decision-making. It also describes how uncertainties and (implicit) normativities concerning GAMC and GI pre-structure the moral environment in which these challenges and norms manifest. We provide normative reflections and recommendations on handling these ethical challenges in a way that is sensitive to the context in which they arise. [ABSTRACT FROM AUTHOR]

Background: In gender-affirming medical care (GAMC), ethical challenges in decision-making are ubiquitous. These challenges are becoming more pressing due to exponentially increasing referrals, politico-legal contestation, and divergent normative views regarding decisional roles and models. Little is known, however, about what ethical challenges related to decision-making healthcare professionals (HCPs) themselves face in their daily work in GAMC and how these relate to, for example, the subjective nature of Gender Incongruence (GI), the multidisciplinary character of GAMC and the role HCPs play in assessing GI and eligibility for interventions. Given the relevance and urgency of these questions, we conducted a qualitative study among HCPs providing GAMC to transgender adults in the Netherlands. Methods: In this qualitative research, we conducted 11 semi-structured interviews between May 2020 and February 2021 with HCPs (six mental health professionals, two HCPs in endocrinology, two in plastic surgery, and one in nursing) working in two distinct GAMC settings. We purposively sampled for professional background and years of experience in GAMC. We analyzed our interview data using thematic analysis. As some respondents were more inclined to speak about what should or ought to be done to arrive at good or right decision-making, we identified both ethical challenges and norms. Furthermore, in our analysis, we differentiated between respondents' explicit and implicit ethical challenges and norms and ascertained the specific context in which these challenges emerged. Results: Respondents' ethical challenges and norms centered on (1) dividing and defining decisional roles and bounds, (2) negotiating decision-making in a (multidisciplinary) team, and (3) navigating various decision-making temporalities. These themes arose in the context of uncertainties regarding (1) GAMC's guidelines, evidence, and outcomes, as well as (2) the boundaries and assessment of GI. Conclusions: This interview study provides detailed empirical insight into both the explicit and implicit ethical challenges that HCPs experience and their ethical norms regarding decision-making. It also describes how uncertainties and (implicit) normativities concerning GAMC and GI pre-structure the moral environment in which these challenges and norms manifest. We provide normative reflections and recommendations on handling these ethical challenges in a way that is sensitive to the context in which they arise. [ABSTRACT FROM AUTHOR]

Structural elucidation of lignin degradation products is a requirement for successfully developing lignin valorization technology. Most of mass spectrometry–based techniques have utilized negative ion mode mass spectrometry for structural elucidation of lignin-derived compounds. Unfortunately, simple deprotonation can lead to in-source fragmentation and may not be suitable for condensed lignin structures without acidic moieties. Herein, we present a lithium cationization methodology for mass spectrometry sequencing of advanced lignin oligomers having β-β′ and β-O-4′ bonding motifs. To do so, two advanced lignin oligomers were first synthesized through a step-by-step synthetic route, and then subjected to two different ESI mass spectrometry techniques in positive ion mode using lithium cations for ionization. An orbitrap mass spectrometer was used to obtain exact mass information, and higher-energy collisional dissociation (HCD) was used to sequence the lignin model oligomers. Based on the sequence-specific fragment ions, sequence rules were proposed. Multi-stage (MSn) collision-induced dissociation (CID) using an ion trap mass spectrometer provided data to investigate the origin of each fragment ion and to further confirm proposed fragmentation pathways. In addition to β-O-4′ bond cleavage, the presented lithium cationization approach led to cleavage of β-β′ bonds on the model oligomers in both ion trap and orbitrap mass spectrometry experiments. Additionally, MSn experiments were used to investigate possible lithium cationization sites on the model oligomers. Lithium cationization in positive ion mode mass spectrometry proved to be a robust tool for characterization and sequencing of advanced lignin oligomers with different bonding motifs. [ABSTRACT FROM AUTHOR]

Successful strategies for the attachment of oligopeptides to mesoporous silica with pores large enough to load biomolecules should utilize the high surface area of pores to provide an accessible, protective environment. A two-step oligopeptide functionalization strategy is examined here using diazirine-based heterobifunctional linkers. Mesoporous silica nanoparticles (MSNPs) with average pore diameter of ~8 nm and surface area of ~730 m2/g were synthesized and amine-functionalized. Tetrapeptides Gly-Gly-Gly-Gly (GGGG) and Arg-Ser-Ser-Val (RSSV), and a peptide comprised of four copies of RSSV (4RSSV), were covalently attached via their N-terminus to the amine groups on the particle surface by a heterobifunctional linker, sulfo-succinimidyl 6-(4,4′-azipentanamido)hexanoate (sulfo-NHS-LC-diazirine, or SNLD). SNLD consists of an amine-reactive NHS ester group and UV-activable diazirine group, providing precise control over the sequence of attachment steps. Attachment efficiency of RSSV was measured using fluorescein isothiocyanate (FITC)-tagged RSSV (RSSV-FITC). TGA analysis shows similar efficiency (0.29, 0.31 and 0.26 mol peptide/mol amine, respectively) for 4G, RSSV and 4RSSV, suggesting a generalizable method of peptide conjugation. The technique developed here for the conjugation of peptides to MSNPs provides for their attachment in pores and can be translated to selective peptide-based separation and concentration of therapeutics from aqueous process and waste streams. [ABSTRACT FROM AUTHOR]

Sensitive, high‐throughput methods for pharmacokinetic (PK) profiling are essential for potential therapeutics during critical stages of clinical trials. The application of a microfluidic capillary zone electrophoresis mass spectrometry (CZE–MS) method for PK profiling allows for rapid, sensitive and in‐depth analysis of multiple samples within a short timeframe. Here, a CZE–MS approach for PK analysis was compared with a traditional UHPLC–MS approach when analyzing serum extracts from rats treated with a potential Alzheimer's disease therapeutic, BNC‐1. Resulting PK data generated from both methods displayed statistical similarities. Additionally, the separation efficiency attributed to the use of the CZE–MS method provided substantial metabolic regulation data that was not apparent in the UHPLC–MS method. Additionally, the coupling of the CZE–MS method to the data processing software, MZmine2, was used to monitor changes in metabolism and observe putative BNC‐1‐derived metabolites. The ability to perform fast analyses without sacrificing sensitivity or metabolic information suggests that this CZE–MS method is ideal for metabolomics‐inclusive, high‐throughput PK profiling. [ABSTRACT FROM AUTHOR]

Over the past decades, great strides have been made to professionalize and increase access to transgender medicine. As the (biomedical) evidence base grows and conceptualizations regarding gender dysphoria/gender incongruence evolve, so too do ideas regarding what constitutes good treatment and decision-making in transgender healthcare. Against this background, differing care models arose, including the 'Standards of Care' and the so-called 'Informed Consent Model'. In these care models, ethical notions and principles such as 'decision-making' and 'autonomy' are often referred to, but left unsubstantiated. This not only transpires into the consultation room where stakeholders are confronted with many different ethical challenges in decision-making, but also hampers a more explicit discussion of what good decision-making in transgender medicine should be comprised of. The aim of this paper is to make explicit the conceptual and normative assumptions regarding decision-making and client autonomy underpinning the 'Standards of Care' and 'Informed Consent Model' currently used in transgender care. Furthermore, we illustrate how this elucidation aids in better understanding stakeholders' ethical challenges related to decision-making. Our ethical analysis lays bare how distinct normative ambiguities in both care models influence decision-making in practice and how foregrounding one normative model for decision-making is no moral panacea. We suggest that the first steps towards good decision-making in gender-affirming medical care are the acknowledgement of its inherent normative and moral dimensions and a shared, dialogical approach towards the decision-making process. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) contamination during fuel ethanol fermentation can lead to significant economic loses. To circumvent this, fuel ethanol plants add antibiotics prophylactically, but their overuse has resulted in the emergence of antibiotic-resistant LAB strains. Lignin is a sustainable biopolymer that can be found as a waste product from lignocellulosic biorefineries. Technical lignins and their smaller phenolic subunits have been shown to exhibit broad-spectrum antimicrobial properties, but there is a lack of demonstrations of lignin derivatives with highly selective properties in the literature. Here, corn stover lignin from a biorefinery was oxidatively depolymerized using an environmentally benign organic oxidant, peracetic acid, into a bio-oil that has selective antimicrobial properties against LAB and not yeasts. The resulting bio-oil demonstrated up to 90% inhibition of commercially sampled LAB (including antibiotic-resistant strains) at 4 mg ml−1 with no inhibition against an industrial yeast strain. These antimicrobial properties of the bio-oil are attributed to larger unidentified lignin oligomers, compared to monolignols, that have a membrane damaging mode of action. Using the bio-oil (4 mg ml−1) during simultaneous saccharification and fermentation (SSF) of raw corn starch showed no inhibition of enzymatic activity, and in LAB contaminated fermentations the bio-oil treatments showed an 8% increase in ethanol yields at higher bacterial contamination ratios (l : 100 yeast to LAB, CFU per ml). This study illustrates the efficacy of using lignin bio-oil as an antibiotic replacement during fuel ethanol fermentation and demonstrates the highly selective antimicrobial properties of lignin oligomers, which creates a viable lignin valorization strategy for biorefineries. [ABSTRACT FROM AUTHOR]

A study of the interaction between cell membranes and small molecules derived from lignin, a protective phenolic biopolymer found in vascular plants, is crucial for identifying their potential as pharmacological and toxicological agents. In this work, the interactions of model cell membranes [supported 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayers] are compared for three βO4 dimers of coniferyl alcohol (G lignin monomer): guaiacylglycerol guaiacol ester with a hydroxypropenyl (HOC3H4-) tail (G-βO4′-G), a truncated GG dimer without HOC3H4- (G-βO4′-truncG), and a benzylated GG dimer (benzG-βO4′-G). The uptake of the lignin dimers (per mass of lipid) and the energy dissipation (a measure of bilayer disorder) are higher for benzG-βO4′-G and G-βO4′-truncG than those for G-βO4′-G in the gel-phase DPPC bilayer, as measured using quartz crystal microbalance with dissipation (QCM-D). A similar uptake of G-βO4′-truncG is observed for a fluid-phase bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine, suggesting that the effect of the bilayer phase on dimer uptake is minimal. The effects of increasing lignin dimer concentration are examined through an analysis of density profiles, potential of mean force curves, lipid order parameters, and bilayer area compressibilities (disorder) in the lipid bilayers obtained from molecular dynamics simulations. Dimer distributions and potentials of mean force indicate that the penetration into bilayers is higher for benzG-βO4′-G and G-βO4′-truncG than that for G-βO4′-G, consistent with the QCM-D results. Increased lipid tail disorder due to dimer penetration leads to a thinning and softening of the bilayers. Minor differences in the structure of lignin derivatives (such as truncating the hydroxypropenyl tail) have significant impacts on their ability to penetrate lipid bilayers. [ABSTRACT FROM AUTHOR]

Background: Glaucomatous eyes often show strong intraocular pressure (IOP) fluctuations and individual measurements at different time points are necessary for personalized therapy. To survey IOP variations 48-hours diurnal and nocturnal IOP measurements were performed on two consecutive days. Aims of this study were to investigate the short-term repeatability of 48-hours measurements within one patient's IOP profile and long-term repeatability between two separate IOP profiles of the same patient.Methods: A retrospective cohort study was performed evaluating data of 90 glaucoma patients in a German university medical center between 2006 and 2013. All patients underwent two separate diurnal IOP profiles of 48 h. IOP was measured at 8 am, 2 pm, 6 pm, 9 pm using Goldmann applanation tonometry and at 12 midnight using Perkins tonometry in supine position on two consecutive days. Intraclass correlation coefficients (ICC) were calculated to evaluate agreement for the same time points (each time point agreement) and for consecutive measurements within the IOP profiles (between time point agreement). ICC ≤ 0.4 was defined as poor agreement, 0.4-0.75 as moderate and ≥ 0.75 as excellent. Differences between time points were investigated by Bland Altman plots.Results: Each time point measurements of profile 1 showed moderate to excellent agreement (ICCs 0.62-0.93). There was a moderate to excellent agreement for measurements between time points of profile 1 (ICCs day one 0.57-0.86, day two 0.71-0.90). Profile 2 was performed at a median interval of 12.0 months (quartiles 11.0 to 21.0). Each time point agreements within profile 2 showed ICCs from 0.23 to 0.81. It showed moderate to excellent agreement for changes between time points (ICCs 0.53-0.94). Day two demonstrated ICCs from 0.74 to 0.88. Long term IOP repeatability (over both pressure profiles) showed moderate to good agreement (ICCs 0.39-0.67).Conclusions: Short and long-term agreement of IOP measurements evaluated by diurnal IOP profiles is moderate to good. Due to mostly moderate agreements, which we believe represent IOP fluctuations, we conclude that it is necessary to perform 48-hours IOP profiles to gain a better overview of the individual IOP fluctuations. [ABSTRACT FROM AUTHOR]

Lignin and lignans are natural products found in plant cell walls. Lignin research has historically focused on lignin degradation techniques in the hope of converting lignin into useful aromatic carbon feedstocks. In contrast, investigations of lignans existing as natural product dimers, have been focused on thier interesting biological activities. Many lignan compounds are chemically identical to dimers derived from lignin, and both lignin and lignan dimers can possess multiple chiral centers leading to observations of diastereomer pairs where one diastereomer exhibits the bulk of the activity. For example, the G-(β-O-4′)-G dimer was reported to have a pro-angiogenic activity with one diastereomer of the pair showing enhanced pro-angiogenic activity. Traditional analytical techniques such as nuclear magnetic resonance (NMR) can differentiate the diastereomer pairs of β-O-4 compounds; however, isolation of a pure sample is often required for analysis. This work was aimed at exploring the potential use of tandem mass spectrometry to differentiate diastereomer pairs in the β-O-4 dimer series. Each diastereomer pair in the nine-dimer series was separated by HPLC and interrogated by tandem mass spectrometry. To understand the chromatographic behavior of the diastereomer pair in the β-O-4 dimer series, three commercially available reverse phase HPLC columns were evaluated. A temperature programming experiment using water/acetonitrile isocratic elution showed that the chromatographic retention mechanism of these diastereomers was hydrophobically driven with analytes having more methoxy groups exhibiting larger ΔH0 and higher octanol-water partition coefficient values. Tandem mass spectrometry performed on each of the diastereomers produced fragment ions having different ion abundances. A mechanistic study based on the ion abundance of "sequence-specific ions" and "-48 ions" was used to assign a configuration to each of the pairs of diastereomers in the nine-dimer series. [ABSTRACT FROM AUTHOR]

Background The majority of hepatitis C virus (HCV) infections are found in low- and middle-income countries, which harbor many region-specific HCV subtypes. Nevertheless, direct-acting antiviral (DAA) trials have almost exclusively been conducted in high-income countries, where mainly epidemically spread HCV subtypes are present. Recently, several studies have demonstrated suboptimal DAA efficacy for certain nonepidemic subtypes, which could hamper global HCV elimination. Therefore, we aimed to evaluate DAA efficacy in patients treated for a nonepidemic HCV genotype infection in the Netherlands. Methods We performed a nationwide retrospective study including patients treated with interferon-free DAAs for an HCV genotype other than 1a/1b/2a/2b/3a/4a/4d. The genotype was determined by NS5B region phylogenetic analysis. The primary end point was SVR-12. If stored samples were available, NS5A and NS5B sequences were obtained for resistance-associated substitutions (RAS) evaluation. Results We included 160 patients, mainly infected with nonepidemic genotype 2 (41%) and 4 (31%) subtypes. Most patients were from Africa (45%) or South America (24%); 51 (32%) were cirrhotic. SVR-12 was achieved in 92% (140/152) of patients with available SVR-12 data. Only 73% (8/11) genotype 3–infected patients achieved SVR-12, the majority being genotype 3b patients with 63% (5/8) SVR. Regardless of SVR, all genotype 3b patients had 30K and 31M RAS. Conclusions The DAA efficacy we observed in most nonepidemic genotypes in the Netherlands seems reassuring. However, the low SVR-12 rate in subtype 3b infections is alarming, especially as it is common in several HCV-endemic countries. Alongside earlier results, our results indicate that a remaining challenge for global HCV elimination is confirming and monitoring DAA efficacy in nonepidemic genotypes. [ABSTRACT FROM AUTHOR]

The growing acceptance and recognition of Surface Guided Radiation Therapy (SGRT) as a promising imaging technique has supported its recent spread in a large number of radiation oncology facilities. Although this technology is not new, many aspects of it have only recently been exploited. This review focuses on the latest SGRT developments, both in the field of general clinical applications and special techniques.SGRT has a wide range of applications, including patient positioning with real-time feedback, patient monitoring throughout the treatment fraction, and motion management (as beam-gating in free-breathing or deep-inspiration breath-hold). Special radiotherapy modalities such as accelerated partial breast irradiation, particle radiotherapy, and pediatrics are the most recent SGRT developments.The fact that SGRT is nowadays used at various body sites has resulted in the need to adapt SGRT workflows to each body site. Current SGRT applications range from traditional breast irradiation, to thoracic, abdominal, or pelvic tumor sites, and include intracranial localizations.Following the latest SGRT applications and their specifications/requirements, a stricter quality assurance program needs to be ensured. Recent publications highlight the need to adapt quality assurance to the radiotherapy equipment type, SGRT technology, anatomic treatment sites, and clinical workflows, which results in a complex and extensive set of tests.Moreover, this review gives an outlook on the leading research trends. In particular, the potential to use deformable surfaces as motion surrogates, to use SGRT to detect anatomical variations along the treatment course, and to help in the establishment of personalized patient treatment (optimized margins and motion management strategies) are increasingly important research topics. SGRT is also emerging in the field of patient safety and integrates measures to reduce common radiotherapeutic risk events (e.g. facial and treatment accessories recognition).This review covers the latest clinical practices of SGRT and provides an outlook on potential applications of this imaging technique. It is intended to provide guidance for new users during the implementation, while triggering experienced users to further explore SGRT applications. [ABSTRACT FROM AUTHOR]

15-5 PH stainless steel (SS) possesses both high strength and good corrosion resistance and is often used in aerospace components. However, age-hardened 15-5 PH SS can lose up to 20% of its strength during fusion welding due to overaging brought on by heat effect. This work addresses the problem of strength reduction observed in 15-5 PH SS by employing the low-heat welding technique of impact welding. Both wrought (W) and additively manufactured (AM) versions of 15–5 PH SS were investigated through experimentation. All workpieces were age-hardened to condition H900 prior to welding. Best weld microstructures and peel strengths were obtained at impact angles of 12°, for both W and AM variants. Peak peel strength for W welds exceeded 178 N/mm, and for AM welds, 141 N/mm. Failure through base material, which was a most desirable failure mode, was obtained for both material types, though further work will be needed to obtain this failure mode repeatably. Thus, the capability of obtaining strong welds with age-hardened 15-5 PH SS was demonstrated. This capability can help eliminate the need for post-weld heat treatment, thus saving significant time and cost and opening up new design possibilities. [ABSTRACT FROM AUTHOR]

This work explores high-speed impact of fully age-hardened 15-5 PH stainless steel with itself at average impact speed of 682 m/s and impact angles ranging from 8° to 28°. It was assumed that higher angles corresponded with higher shear stresses at impact point. Microstructural examination indicated more pronounced shear-induced features at higher angles, such as nanoscale elongated grains and adiabatic shear bands. Interfacial waves, a feature associated with impact welding, were most prominent at 12° and 16°. White etching layers (WELs), a constituent formed by rapid heating and cooling at impact, were found along the impact interface and most prominently at the front and back vortices of the interfacial waves. WELs (along the interface) were softer than base materials due to overaging, whereas materials surrounding the interface were harder than base materials due to grain refinement. Numerical simulations based on smoothed particle hydrodynamics method were employed to predict the local temperature and strain distributions which supported microstructural findings. Thus, through high-speed impact experiments carried out at different angles along with advanced microscopy and numerical simulations, this work helped reveal the microstructural response of 15-5 PH stainless steel in a range of dynamic shear conditions. [ABSTRACT FROM AUTHOR]

Electrospray ionization mass spectrometry has recently become the technique of choice for rapid characterization of lignin degradation products. However, the fundamental question of the relationship between lignin structure and ionization efficiency has not been explored. In this work, we studied the electrospray ionization response of five structurally similar β‐O‐4′ model lignin compounds using lithium cationization in the positive electrospray ionization mode. The studied compounds have the same β‐O‐4′ backbone structure but differ at the α‐position by increasing nonpolar side chains. Our results show a correlation between the ionization response and the length of the nonpolar side chain, with analytes having the longest side chain recording the highest ESI response in the full scan mode. Factors affecting the formation of analyte ions and analyte cluster ions were also studied. We have shown for the first time in this work that the introduction of a nonpolar group onto a β‐O‐4′ lignin compound can increase the lithium cationization ESI response in the positive ion mode. [ABSTRACT FROM AUTHOR]

Rationale: Effective analytical techniques are needed to characterize lignin products for the generation of renewable carbon sources. Application of matrix‐assisted laser desorption/ionization (MALDI) in lignin analysis is limited because of poor ionization efficiency. In this study, we explored the potential of cationization along with a 2,5‐dihydroxyacetophenone (DHAP) matrix to characterize model lignin oligomers. Methods: Synthesized lignin oligomers were analyzed using the developed MALDI method. Two matrix systems, DHAP and α‐cyano‐4‐hydroxycinnamic acid (CHCA), and three cations (lithium, sodium, silver) were evaluated using a Bruker UltraFlextreme time‐of‐flight mass spectrometer. Instrumental parameters, cation concentration, matrix, sample concentrations, and sample spotting protocols were optimized for improved results. Results: The DHAP/Li+ combination was effective for dimer analysis as lithium adducts. Spectra from DHP and ferric chloride oligomers showed improved signal intensities up to decamers (m/z 1823 for the FeCl3 system) and provided insights into differences in the oligomerization mechanism. Spectra from a mixed DHP oligomer system containing H, G, and S units showed contributions from all monolignols within an oligomer level (e.g. tetramer level). Conclusions: The DHAP/Li+ method presented in this work shows promise to be an effective analytical tool for lignin analysis by MALDI and may provide a tool to assess lignin break‐down efforts facilitating renewable products from lignin. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to assess the reduction in dose to the penile bulb (PB) achieved by MRI-based contouring following drinking and endorectal balloon (ERB) instructions.Patients and Methods: A total of 17 prostate cancer patients were treated with intensity-modulated radiation therapy (IMRT) and interstitial brachytherapy (IBT). CT and MRI datasets were acquired back-to-back based on a 65 cm3 air-filled ERB and drinking instructions. After rigid co-registration of the imaging data, the CT-based planning target volume (PTV) used for treatment planning was retrospectively compared to an MRI-based adaptive PTV and the dose to the PB was determined in each case. The adapted PTV encompassed a caudally cropped CT-based PTV which was defined on the basis of the MRI-based prostate contour plus an additional 5 mm safety margin.Results: In the seven-field IMRT treatment plans, the MRI-based adapted PTV achieved mean (Dmean) and maximum (Dmax) doses to the PB which were significantly lower (by 7.6 Gy and 10.9 Gy, respectively; p <0.05) than those of the CT-contoured PTV. For 6 patients, the estimated PB Dmax (seven-field IMRT and IBT) for the adapted PTV was <70 Gy, whereas only 1 patient fulfilled this criterium with the CT-based PTV.Conclusion: MRI-based contouring and seven-field IMRT-based treatment planning achieved dose sparing to the PB. Whereas the comparison of MRI and CT contouring only relates to external beam radiotherapy (EBRT) sparing, considering EBRT and IBT shows the improvement in PB sparing for the total treatment. [ABSTRACT FROM AUTHOR]

What can trading stamps do for the small retailer? A survey of Indianapolis merchants-stamp users, ex-users, and nonusers--shows that those in strong competitive positions, who adopted stamps soon after they were introduced in the market, and promoted them aggressively had best results. [ABSTRACT FROM AUTHOR]

Complete genome sequencing of dozens of strains of the soil bacterium Rhodococcus has revealed the presence of many cryptic biosynthetic gene clusters, presumably dedicated to the production of small molecules. This has sparked a renewed interest in this underexplored member of the Actinobacteria as a potential source of new bioactive compounds. Reported here is the discovery of a potent inhibitory molecule produced by a newly isolated strain of Rhodococcus, strain MTM3W5.2. This small inhibitory molecule shows strong activity against all Rhodococcus species tested, including the veterinary pathogen R. equi, and some closely related genera. It is not active against other Gram positive or Gram negative bacteria. A screen of random transposon mutants identified a gene required to produce this inhibitory compound. This gene is a large multi-domain, type I polyketide synthase that is part of a very large multi-gene biosynthetic gene cluster in the chromosome of strain MTM3W5.2. The high resolution mass spectrum of a major chromatogram peak from a broth culture extract of MTM3W5.2 shows the presence of a compound at m/z 911.5490 atomic mass units. This compound is not detected in the culture extracts from a non-producing mutant strain of MTM3W5.2. A large gene cluster containing at least 14 different type I polyketide synthase genes is proposed to be required to synthesize this antibiotic-like compound. [ABSTRACT FROM AUTHOR]

Treatment teams providing transgender-affirming medical care are inherently faced with various kinds of moral and ethical dilemmas and questions, which are becoming even more pressing due to increasing treatment numbers and public attention for transgender care. Little is known about what kinds of moral and ethical challenges manifest in clinical practice. The aim of the present research was to map the moral and ethical challenges of healthcare professionals working in a specialized multidisciplinary transgender care center. Over a period of 7 months, during a focused ethnographic study, data were collected through participant observation of multidisciplinary team meetings, observation of individual psychodiagnostic assessment sessions with clients, and analysis of transcripts and reports of a series of moral case deliberations. A thematic content analysis of the data identified various implicit and explicit moral and ethical challenges around the following six themes: (1) assessing eligibility; (2) content of treatment; (3) sequential order of the treatment steps; (4) role of the clinical guidelines; (5) differing notions regarding gender identity, and (6) decision-making process. Our research provides a detailed insight into the way healthcare professionals experience these moral and ethical challenges and how they are related to (local) guidelines, the multidisciplinary character of GD care, and its inherent implicit and explicit gender norms. Our findings suggest that good transgender care may profit from continuous multidisciplinary deliberation of and sensitivity toward the normative dimension of transgender care. The paper ends with recommendations for ethics support mechanisms in transgender care. [ABSTRACT FROM AUTHOR]

Background: Although elevated serum levels of visinin-like protein 1 (VILIP-1), a neuron-specific calcium sensor protein, are associated with ischaemic stroke, only a single study has evaluated VILIP-1 as a biomarker of traumatic brain injury (TBI). The current proof-of-concept study was designed to determine whether serum VILIP-1 levels increase post-injury in a well-characterized rat unilateral cortical contusion model. Methods: Lateral flow devices (LFDs) rapidly (< 20 min) detected trace serum levels (pg/mL) of VILIP-1 in a small input sample volume (10 µL). Temporal profiles of serum levels at baseline and post-injury were measured in male Sprague Dawley rats subjected to very mild-, mild unilateral-cortical contusion, or naïve surgery and in male Sprague Dawley rats following a diffuse TBI or sham surgery. Results: Mean serum levels were significantly elevated by 0.5 h post-injury and remained so throughout the temporal profile compared with baseline in very mild and mild unilateral contusions but not in naïve surgeries. Serum levels were also elevated in a small cohort of animals subjected to a diffuse TBI injury. Conclusions: Overall, the current study demonstrates that the novel LFD is a reliable and rapid point-of-care diagnostic for the detection and quantification of serum levels of UB-VILIP-1 in a clinically relevant time frame. [ABSTRACT FROM AUTHOR]

2b (+) HCD mass spectrum of trimer SSG analyzed as Li adduct Graph Fig. Publisher Correction to Application of lithium cationization tandem mass spectrometry for structural analysis of lignin model oligomers with - ' and -O-4' linkages 4b (+) HCD mass spectrum of GSSG tetramer analyzed as Li adduct Publisher's note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. [Extracted from the article]

Electrospray ionization mass spectrometry ESI-MS is a powerful technique for the characterization of macromolecules and their noncovalent binding with guest ions. We herein evaluate the feasibility of using ESI-MS as a screening tool for predicting potentiometric selectivities of ionophores. Ion-selective electrodes based on the cyclic peptide, cyclosporin A, were developed, and their potentiometric selectivity pattern was evaluated. Optimized electrodes demonstrated near-Nernstian slopes with micromolar detection limits toward calcium. ESI-MS and ESI-MS/MS were employed to determine the relative association strengths of cyclosporin A with various cations. The observed MS intensities of ion–ionophore complexes correlate favorably with the potentiometric selectivity pattern that was demonstrated by cyclosporin-based electrodes. This correlation was found to hold true for other established ionophores, such as valinomycin and benzo-18-crown-6. Taken together, these experiments demonstrate that mass spectrometry could be used to predict the selectivity patterns of new ionophores for potentiometric and optical ion sensors. Further, this approach could be useful in screening mixtures or libraries of newly-synthesized compounds to identify selective ionophores. [ABSTRACT FROM AUTHOR]

Background: Laboratory analysis and optical quality assessment of explanted hydrophilic intraocular lenses (IOLs) with clinically significant opacification after posterior lamellar keratoplasty (DMEK and DSAEK).Methods: Thirteen opacified IOLs after posterior lamellar keratoplasty, 8 after descemet stripping automated endothelial keratoplasty (DSAEK), 3 after descemet membrane endothelial keratoplasty (DMEK) and 2 after both DSAEK and DMEK were analysed in our laboratory. Analyses included optical bench assessment for optical quality, light microscopy, scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS).Results: In all IOLs the opacification was caused by a thin layer of calciumphosphate that had accumulated underneath the anterior optical surface of the IOLs in the area spared by the pupil/anterior capsulorhexis. The calcifications lead to a significant deterioration of the modulation transfer function across all spatial frequencies of the affected IOLs.Conclusions: The instillation of exogenous material such as air or gas into the anterior chamber increases the risk for opacification of hydrophilic IOLs irrespective of the manufacturer or the exact composition of the hydrophilic lens material. It is recommended to avoid the use of hydrophilic acrylic IOLs in patients with endothelial dystrophy that will likely require procedures involving the intracameral instillation of air or gas, such as DMEK or DS(A)EK. [ABSTRACT FROM AUTHOR]

Ocular gene therapy approaches have been developed for a variety of different diseases. In particular, clinical gene therapy trials for RPE65 mutations, X-linked retinoschisis, and choroideremia have been conducted at different centers in recent years, showing that adeno-associated virus (AAV)-mediated gene therapy is safe, but limitations exist as to the therapeutic benefit and long-term duration of the treatment. The technique of vector delivery to retinal cells relies on subretinal injection of the vector solution, causing a transient retinal detachment. Although retinal detachments are known to cause remodeling of retinal neuronal structures as well as significant cell loss, the possible effects of this short-term therapeutic retinal detachment on retinal structure and circuitry have not yet been studied in detail. In this study, retinal morphology and apoptotic status were examined in healthy rat retinas following AAV-mediated gene transfer via subretinal injection with AAV2/5.CMV.d2GFP or sham injection with fluorescein. Outer plexiform layer (OPL) morphology was assessed by immunohistochemical labeling, laser scanning confocal microscopy, and electron microscopy. The number of synaptic contacts in the OPL was quantified after labeling with structural markers. To assess the apoptotic status, inflammatory and pro-apoptotic markers were tested and TUNEL assay for the detection of apoptotic nuclei was performed. Pre- and postsynaptic structures in the OPL, such as synaptic ribbons or horizontal and bipolar cell processes, did not differ in size or shape in injected versus non-injected areas and control retinas. Absolute numbers of synaptic ribbons were not altered. No signs of relevant gliosis were detected. TUNEL labeling of retinal cells did not vary between injected and noninjected areas, and apoptosis-inducing factor was not delocalized to the nucleus in transduced areas. The neuronal circuits in the OPL of healthy rat retinas undergoing AAV-mediated gene transfer were not altered by the temporary retinal detachment caused by subretinal injection, the presence of viral particles, or the expression of green fluorescent protein as a transgene. This observation likely requires further investigations in the dog model for RPE65 deficiency in order to determine the impact of RPE65 transgene expression on diseased retinas in animals and men. [ABSTRACT FROM AUTHOR]

Ubiquitin carboxyl -terminal hydrolase L-1 (UCH L-1) is a crucial enzyme for proteasomal protein degradation that generates free monomeric ubiquitin. Our previous proteomic study identified UCH L-1 as one specific target of protein oxidation in Alzheimer's disease (AD) brain, establishing a link between the effect of oxidative stress on protein and the proteasomal dysfunction in AD. However, it is unclear how protein oxidation affects function, owing to the different responses of proteins to oxidation. Analysis of systems in which the oxidized protein displays lowered or null activity might be an excellent model for investigating the effect of the protein of interest in cellular metabolism and evaluating how the cell responds to the stress caused by oxidation of a specific protein. The gracile axonal dystrophy ( gad) mouse is an autosomal recessive spontaneous mutant with a deletion on chromosome 5 within the gene encoding UCH L-1. The mouse displays axonal degeneration of the gracile tract. The aim of this proteomic study on gad mouse brain, with dysfunctional UCH L-1, was to determine differences in brain protein oxidation levels between control and gad samples. The results showed increased protein oxidation in thioredoxin peroxidase (peroxiredoxin), phosphoglycerate mutase, Rab GDP dissociation inhibitor α/ATP synthase and neurofilament-L in the gad mouse brain. These findings are discussed with reference to the effect of specific protein oxidation on potential mechanisms of neurodegeneration that pertain to the gad mouse. [ABSTRACT FROM AUTHOR]

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Because traditional approaches to drug development for Alzheimer's disease are becoming increasingly expensive and in many cases disappointingly unsuccessful, alternative approaches are required to shift the paradigm. Following leads from investigations of dihydropyridine calcium channel blockers, we observed unique properties from a class of functionalized naphthyridines and sought to develop these as novel therapeutics that minimize amyloid pathology without the adverse effects associated with current therapeutics. Our data show methyl 2,4-dimethyl-5-oxo-5,6-dihydrobenzo[c][2,7]naphthyridine-1-carboxylate (BNC-1) significantly decreases amyloid burden in a well-established mouse model of amyloid pathology through a unique mechanism mediated by Elk-1, a transcriptional repressor of presenilin-1. Additionally, BNC-1 treatment leads to increased levels of synaptophysin and synapsin, markers of synaptic integrity, but does not adversely impact presenilin-2 or processing of Notch-1, thus avoiding negative off target effects associated with pan-gamma secretase inhibition. Overall, our data show BNC-1 significantly decreases amyloid burden and improves markers of synaptic integrity in a well-established mouse model of amyloid deposition by promoting phosphorylation and activation of Elk-1, a transcriptional repressor of presenilin-1 but not presenilin-2. These data suggest BNC-1 might be a novel, disease-modifying therapeutic that will alter the pathogenesis of Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Specific biomarkers in a readily accessible biological fluid, such as blood, could aid in the identification, characterization, validation, and routine monitoring of Alzheimer's disease (AD) progression. In the current study, levels of the previously described novel cerebrospinal fluid aberrant protein complex composed of prostaglandin-D-synthase (PDS) and transthyretin (TTR) were quantified in plasma by a custom two-probe sandwich ELISA and compared to amyloid-β (Aβ)(1-42) as a standard plasma biomarker of AD. Plasma was analyzed from 140 probable AD subjects, 135 subjects with mild cognitive impairment (MCI), 74 normal control subjects (NC) prior to MCI transition, 23 diseased control (DC) subjects with either frontotemporal dementia or dementia with Lewy bodies, and 182 normal control (NC) subjects who did not progress to MCI or dementia. Levels of Aβ(1-42) were significantly elevated in NC subjects prior to MCI conversion but significantly reduced in probable AD subjects compared to NC subjects. Similarly, levels of the PDS-TTR complex were significantly reduced in both MCI and probable AD subjects compared to NC subjects. Furthermore, levels of Aβ(1-42) and the PDS-TTR complex were not significantly different in DC subjects compared to NC subjects. MMSE scores were weakly but significantly correlated with plasma levels of the PDS-TTR complex and Aβ(1-42). Trail B scores were weakly but significantly correlated with plasma levels of Aβ(1-42). Comparison of receiver operating curves shows the PDS-TTR complex is comparable to Aβ(1-42) in both MCI and probable AD subjects. [ABSTRACT FROM AUTHOR]

Purpose: Particle therapy (PT) has advantages over photon irradiation on static tumors. An increased biological effectiveness and active target conformal dose shaping are strong arguments for PT. However, the sensitivity to changes of internal geometry complicates the use of PT for moving organs. In case of interfractionally moving objects adaptive radiotherapy (ART) concepts known from intensity modulated radiotherapy (IMRT) can be adopted for PT treatments. One ART strategy is to optimize a new treatment plan based on daily image data directly before a radiation fraction is delivered [treatment replanning (TRP)]. Optimizing treatment plans for PT using a scanned beam is a time consuming problem especially for particles other than protons where the biological effective dose has to be calculated. For the purpose of TRP, fast optimization and fast dose calculation have been implemented into the GSI in-house treatment planning system (TPS) TRiP98. Methods: This work reports about the outcome of a code analysis that resulted in optimization of the calculation processes as well as implementation of routines supporting parallel execution of the code. To benchmark the new features, the calculation time for therapy treatment planning has been studied. Results: Compared to the original version of the TPS, calculation times for treatment planning (optimization and dose calculation) have been improved by a factor of 10 with code optimization. The parallelization of the TPS resulted in a speedup factor of 12 and 5.5 for the original version and the code optimized version, respectively. Hence the total speedup of the new implementation of the authors' TPS yielded speedup factors up to 55. Conclusions: The improved TPS is capable of completing treatment planning for ion beam therapy of a prostate irradiation considering organs at risk in this has been overseen in the review process. Also see below 6 min. [ABSTRACT FROM AUTHOR]

Purpose: The use of motion mitigation techniques such as tracking and gating in particle therapy requires real-time knowledge of tumor position with millimeter precision. The aim of this phantombased study was to evaluate the option of diagnostic ultrasound (US) imaging (sonography) as real-time motion detection method for scanned heavy ion beam irradiation of moving targets. Methods: For this pilot experiment, a tumor surrogate was moved inside a water bath along twodimensional trajectories. A rubber ball was used for this purpose. This ball was moved by a robotic arm in two dimensions lateral to the heavy ion beam. Trajectories having a period of 3 s and peak to peak amplitude of 20 mm were used. Square radiation fields of 3 × 3 cm² were irradiated on radiosensitive films with a 200 MeV/u beam of calcium ions having a FWHM of 6 mm. Pencil beam scanning and beam tracking were employed. The films were attached on the robotic arm and thus moved with the rubber ball. The position of the rubber ball was continuously measured by a US tracking system (Mediri GmbH, Heidelberg) and sent to the GSI therapy control system (TCS). This position was used as tracking vector. Position reconstruction from the US tracking system and data communication introduced a delay leading to a position error of several millimeters. An artificial neural network (ANN) was implemented in the TCS to predict motion from US measurements and thus to compensate for the delay. Results: Using ANN delay compensation and large motion amplitudes, the authors could produce irradiation patterns with a few percent inhomogeneity and about 1 mm geometrical conformity. Conclusions: This pilot experiment suggests that diagnostic US should be further investigated as dose-free, high frame-rate, and model-independent motion detection method for scanning heavy ion beam irradiation of moving targets. [ABSTRACT FROM AUTHOR]

Studies of oxidative damage during the progression of Alzheimer's disease ( AD) suggest its central role in disease pathogenesis. To investigate levels of nucleic acid oxidation in both early and late stages of AD, levels of multiple base adducts were quantified in nuclear and mitochondrial DNA from the superior and middle temporal gyri ( SMTG), inferior parietal lobule ( IPL), and cerebellum ( CER) of age-matched normal control subjects, subjects with mild cognitive impairment, preclinical AD, late-stage AD, and non- AD neurological disorders (diseased control; DC) using gas chromatography/mass spectrometry. Median levels of multiple DNA adducts in nuclear and mitochondrial DNA were significantly ( p ≤ 0.05) elevated in the SMTG, IPL, and CER in multiple stages of AD and in DC subjects. Elevated levels of fapyguanine and fapyadenine in mitochondrial DNA suggest a hypoxic environment early in the progression of AD and in DC subjects. Overall, these data suggest that oxidative damage is an early event not only in the pathogenesis of AD but is also present in neurodegenerative diseases in general. [ABSTRACT FROM AUTHOR]

Background and study aims: This study aimed to reassess whether the Forrest classification is still useful for the prediction of rebleeding and mortality in peptic ulcer bleedings and, based on this, whether the classification could be simplified. Patients and methods: Prospective registry data on peptic ulcer bleedingswere collected and categorized according to the Forrest classification. The primary outcomes were 30-day rebleeding and all-cause mortality rates. Receiver operating characteristic curves were used to test whether simplification of the Forrest classification into high risk (Forrest Ia), increased risk (Forrest Ib -IIc), and low risk (Forrest III) classes could be an alternative to the original classification. Results: In total, 397 patients were included, with 18 bleedings (4.5 %) being classified as Forrest Ia, 73 (18.4 %) as Forrest Ib, 86 (21.7 %) as Forrest IIa, 32 (8.1 %) as Forrest IIb, 59 (14.9 %) as Forrest IIc, and 129 (32.5 %) as Forrest III. Rebleeding occurred in 74 patients (18.6 %). Rebleeding rates were highest in Forrest Ia peptic ulcers (59 %). The odds ratios for rebleeding among Forrest Ib -IIc ulcers were similar. In subgroup analysis, predicting rebleeding using the Forrest classificationwas more reliable for gastric ulcers than for duodenal ulcers. The simplified Forrest classification had similar test characteristics to the original Forrest classification. Conclusion: The Forrest classification still has predictive value for rebleeding of peptic ulcers, especially for gastric ulcers; however, it does not predict mortality. Based on these results, a simplified Forrest classification is proposed. However, further studies are needed to validate these findings. [ABSTRACT FROM AUTHOR]

Gating is one option for radiotherapy of tumours that move intrafractionally due to respiration. Delays of the motion monitoring system can lead to a shift of the gating window and thus slightly shifted dose distributions. We studied the delay of two motion monitoring systems which use the motion of the chest wall as surrogate for tumour motion. Delays and their dosimetric influence were determined against a precise motion acquisition system in a phantom study. The measurement data were supplemented by dedicated simulations of the experimental setup. Finally, the dosimetric influence for patient treatments was estimated for a lung tumour case using the extreme situation of a radiosurgery setting with a single field. We determined delays of 132 ± 18 ms and 103 ± 22 ms for the two systems. There was no significant difference between beam start and beam stop delay. Even for delays of 200 ms the dosimetric influence in a single-field radiosurgery setting is moderate (V95 = 96.5%, V107 = 8.5%, D5-D95 = 13%). We conclude, that the delay of the motion monitoring system should be part of the commissioning process for gated treatments. The dosimetric impact should be studied in detail prior treatments with a scanned ion beam. [ABSTRACT FROM AUTHOR]

In-beam positron emission tomography (PET) has been proven to be a reliable technique in ion beam radiotherapy for the in situ and non-invasive evaluation of the correct dose deposition in static tumour entities. In the presence of intra-fractional target motion an appropriate time-resolved (four-dimensional, 4D) reconstruction algorithm has to be used to avoid reconstructed activity distributions suffering from motion-related blurring artefacts and to allow for a dedicated dose monitoring. Four-dimensional reconstruction algorithms from diagnostic PET imaging that can properly handle the typically low counting statistics of in-beam PET data have been adapted and optimized for the characteristics of the double-head PET scanner BASTEI installed at GSI Helmholtzzentrum Darmstadt, Germany (GSI). Systematic investigations with moving radioactive sources demonstrate the more effective reduction ofmotion artefacts by applying a 4D maximum likelihood expectation maximization (MLEM) algorithm instead of the retrospective co-registration of phasewise reconstructed quasi-static activity distributions. Further 4D MLEM results are presented from in-beam PET measurements of irradiated moving phantoms which verify the accessibility of relevant parameters for the dose monitoring of intra-fractionally moving targets. From in-beam PET listmode data sets acquired together with a motion surrogate signal, valuable images can be generated by the 4D MLEM reconstruction for different motion patterns and motion-compensated beam delivery techniques. [ABSTRACT FROM AUTHOR]

Accurate dose delivery to extra-cranial lesions requires tumor motion compensation. An effective compensation can be achieved by real-time tracking of the target position, either measured in fluoroscopy or estimated through correlation models as a function of external surrogate motion. In this work, we integrated two internal/external correlation models (a state space model and an artificial neural network-based model) into a custom infra-red optical tracking system (OTS). Dedicated experiments were designed and conducted at GSI (Helmholtzzentrum für Schwerionenforschung). A robotic breathing phantom was used to reproduce regular and irregular internal target motion as well as external thorax motion. The position of a set of markers placed on the phantom thorax was measured with the OTS and used by the correlation models to infer the internal target position in real-time. Finally, the estimated target position was provided as input for the dynamic steering of a carbon ion beam.Geometric results showed that the correlation models transversal (2D) targeting error was always lower than 1.3 mm (root mean square). A significant decrease of the dosimetric error with respect to the uncompensated irradiation was achieved in four out of six experiments, demonstrating that phase shifts are the most critical irregularity for external/internal correlation models [ABSTRACT FROM AUTHOR]

Purpose: Upgrade and benchmarking of a research 4D treatment planning system (4DTPS) suitable for realistic patient treatment planning and treatment simulations taking into account specific requirements for scanned ion beam therapy, i.e., modeling of dose heterogeneities due to interplay effects and range changes caused by patient motion and dynamic beam delivery. Methods: The 4DTPS integrates data interfaces to 4D computed tomography (4DCT), deformable image registration and clinically used motion monitoring devices. The authors implemented a novel data model for 4D image segmentation using Boolean mask volume datasets and developed an algorithm propagating a manually contoured reference contour dataset to all 4DCT phases. They further included detailed treatment simulation and dose reconstruction functionality, based on the irregular patient motion and the temporal structure of the beam delivery. The treatment simulation functionality was validated against experimental data from irradiation of moving radiographic films in air, 3D moving ionization chambers in a water phantom, and moving cells in a biological phantom with a scanned carbon ion beam. The performance of the program was compared to results obtained with predecessor programs. Results: The measured optical density distributions of the radiographic films were reproduced by the simulations to (-2 ± 12)%. Compared to earlier versions of the 4DTPS, the mean agreement improved by 2%, standard deviations were reduced by 7%. The simulated dose to the moving ionization chambers in water showed an agreement with the measured dose of (-1 ± 4)% for the typical beam configuration. The mean deviation of the simulated from the measured biologically effective dose determined via cell survival was (617 ± 538) mGy relative biological effectiveness corresponding to (10 ± 9)%. Conclusions: The authors developed a research 4DTPS suitable for realistic treatment planning on patient data and capable of simulating dose delivery to a moving patient geometry for scanned ion beams. The accuracy and reliability of treatment simulations improved considerably with respect to earlier versions of the 4DTPS. [ABSTRACT FROM AUTHOR]

Particle therapy positron emission tomography (PT-PET) allows for an in vivo and in situ verification of applied dose distributions in ion beam therapy. Since the dose distribution cannot be extracted directly from the β+-activity distribution gained from the PET scan the validation is done by means of a comparison between the reconstructed β+-activity distributions from a PT-PET measurement and from a PT-PET simulation. Thus, the simulation software for generating PET data predicted from the treatment planning is an essential part of the dose verification routine. For the dose monitoring of intra-fractionally moving target volumes the PET data simulation needs to be upgraded by using time resolved (4D) algorithms to account correctly for the motion dependent displacement of the positron emitters. Moreover, it has to consider the time dependent relative movement between target volume and scanned beam to simulate the accurate positron emitter distribution generated during irradiation. Such a simulation program is presented which properly proceeds with motion compensated dose delivery by scanned ion beams to intra-fractionally moving targets. By means of a preclinical phantom study it is demonstrated that even the sophisticated motion-mitigated beam delivery technique of range compensated target tracking can be handled correctly by this simulation code. The new program is widely based on the 3DPT-PET simulation program which had been developed at the Helmholtz-Zentrum Dresden-Rossendorf, Germany (HZDR) for application within a pilot project to simulate in-beam PET data for about 440 patients with static tumor entities irradiated at the former treatment facility of the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany (GSI). A simulation example for a phantom geometry irradiated with a tracked 12C-ion beam is presented for demonstrating the proper functionality of the program. [ABSTRACT FROM AUTHOR]