Plasma tryptophan pathway metabolites quantified by liquid chromatography-tandem mass spectrometry as biomarkers in neuroendocrine tumor patients

A good and accessible biomarker is of great clinical value in neuroendocrine tumor (NET) patients, especially considering its frequently indolent nature and long-term follow-up. Plasma chromogranin A (CgA) and 5-hydroxyindoleacetic acid (5-HIAA) are currently used as biomarkers in NET, but their sensitivity and specificity are restricted. 5-HIAA is the main metabolite of serotonin, an important neurotransmitter of the tryptophan pathway. The aim of this study is to estabish a sensitive and accurate method for the quantification of tryptophan pathway metabolites in plasma. We further aimed to evaluate its utility as a clinical tool in NET disease. We obtained plasma samples from NET patients and healthy controls recruited from the University Hospital of North Norway, Tromsø. Samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and eight metabolites of the tryptophan pathway were quantified. We included 130 NET patients (72/130 small intestinal [SI] NET, 35/130 pancreatic NET, 23/130 other origin) and 20 healthy controls. In the SI-NET group, 26/72 patients presented with symptoms of carcinoid syndrome (CS). We found that combining tryptophan metabolites into a serotonin/kynurenine pathway ratio improved diagnostic sensitivity (92.3%) and specificity (100%) in detecting CS patients from healthy controls compared with plasma 5-HIAA alone (sensitivity 84.6%/specificity 100%). Further, a clinical marker based on the combination of plasma serotonin, 5-HIAA, and 5OH-tryptophan, increased diagnostic capacity identifying NET patients with metastasized disease from healthy controls compared with singular plasma 5-HIAA, serotonin, or CgA. In addition, this marker was positive in 61% of curatively operated SI-NET patients compared with only 10% of healthy controls (p < .001). Our results indicate that simultaneous quantification of several tryptophan metabolites in plasma, using LC-MS/MS, may represent a clinically useful diagnostic tool in NET disease.

Geochemical analyses of metal(loid) fractions do not predict plant uptake behavior: Are plant bioassays better tools to predict mine rehabilitation success?

Management of metal(loid) tailings at historic sites presents environmental hazards usually requiring rehabilitation to mitigate pollution risks. Strategies employed include capping or establishing vegetation directly, which requires tailings assessments to determine suitable rehabilitation approaches. Assessments are typically geochemical analyses, but plant based approaches may provide a more accurate measure of revegetation success although they are often limited to germination indices. This study uses the plant bioassay (Rhizotest™) with common geochemical assessment to predict plant uptake of metal(loid)s and the subsequent likely rehabilitation success. Pb/Zn tailings from five legacy sites within the UK and Ireland were characterized for pH, EC, water soluble and CaCl₂-extractable content and aqua regia extractable content. Uptake of Sb, As, Cd, Cu, Ca, Mg, Mn, Zn, Pb was determined in shoots and roots of Lolium perenne. Total Zn, Pb, Sb, Cd and As in tailings ranged from 694 to 2683 mg kg^-1, 1252 to 8072 mg kg^-1, 14 to 148 mg kg^-1, 1.3 to 44 mg kg^-1 and 1.3 to 45 mg kg^-1, respectively. The only correlation found between total and water soluble or CaCl₂-extractable metal(loid) contents was for Cd, where r = 0.8 for total and CaCl₂-extractable fractions. Limited uptake and translocation risk was identified for major contaminants Zn and Pb in most tailings samples but in some cases exceedance of phytotoxic threshold values occurred that was not reflected in geochemical analysis. Crucially, although total Cd and Sb content was relatively low (< 20 mg kg^-1) in some tailings, elevated plant content for some samples highlights phytotoxic risk from minor elements. Results indicate that screening based on geochemical content is not sufficiently predictive of metal(loid) phytoavailability to reliably inform mine rehabilitation strategies. We therefore strongly recommend that geochemical analyses are supplemented with plant based bioassay to plan mine tailings revegetation and reduce risk of wider ecosystem metal(loid) transfer.

Antitumor activity of ipilimumab or BRAF ± MEK inhibition after pembrolizumab treatment in patients with advanced melanoma: analysis from KEYNOTE-006

BACKGROUND

Antitumor activity of ipilimumab or BRAF ± MEK inhibitors (BRAFi ± MEKi) following pembrolizumab administration in melanoma is poorly characterized.

PATIENTS AND METHODS

In the phase III KEYNOTE-006 study, patients with unresectable stage III/IV melanoma received pembrolizumab (10 mg/kg) once every 2 or 3 weeks (Q3W) or ipilimumab (3 mg/kg) Q3W. The current post hoc analysis evaluates outcomes with ipilimumab or BRAFi ± MEKi as first subsequent systemic therapy after pembrolizumab administration and includes patients who completed or discontinued pembrolizumab after one or more dose. Pembrolizumab arms were pooled.

RESULTS

At data cut-off (4 December 2017), median follow-up was 46.9 months. Of 555 pembrolizumab-treated patients, first subsequent therapy was ipilimumab for 103 (18.6%) and BRAFi ± MEKi for 59 (10.6%) [33 received BRAFi + MEKi, 26 BRAFi alone; 37 (62.7%) were BRAFi ± MEKi naïve]. In the subsequent ipilimumab group, ORR with previous pembrolizumab was 17.5% [1 complete response (CR); 17 partial response (PR)]; 79.6% had discontinued pembrolizumab due to progressive disease (PD); median overall survival (OS) was 21.5 months. ORR with subsequent ipilimumab was 15.5%; 11/16 responses (8 CRs; 3 PRs) were ongoing. ORR with subsequent ipilimumab was 9.7% for patients with PD as best response to pembrolizumab. Median OS from ipilimumab initiation was 9.8 months. In the subsequent BRAFi ± MEKi group, ORR with previous pembrolizumab was 13.5% (8 PR); 76.3% had discontinued pembrolizumab due to PD; median OS was 17.9 months. ORR with subsequent BRAFi ± MEKi was 30.5%, 7/18 responses (4 CR, 3 PR) were ongoing. Median OS from BRAFi ± MEKi initiation was 12.9 months. ORR for BRAFi ± MEKi-naïve patients who received subsequent BRAFi ± MEKi was 43.2%; 6/16 were ongoing (3 CR, 3 PR).

CONCLUSIONS

Ipilimumab and BRAFi ± MEKi have antitumor activity as first subsequent therapy after pembrolizumab in patients with advanced melanoma.

Frictional Melting in Hydrothermal Fluid-Rich Faults: Field and Experimental Evidence From the Bolfín Fault Zone (Chile)

Tectonic pseudotachylytes are thought to be unique to certain water-deficient seismogenic environments and their presence is considered to be rare in the geological record. Here, we present field and experimental evidence that frictional melting can occur in hydrothermal fluid-rich faults hosted in the continental crust. Pseudotachylytes were found in the >40 km-long Bolfín Fault Zone of the Atacama Fault System, within two ca. 1 m-thick (ultra)cataclastic strands hosted in a damage-zone made of chlorite-epidote-rich hydrothermally altered tonalite. This alteration state indicates that hydrothermal fluids were active during the fault development. Pseudotachylytes, characterized by presenting amygdales, cut and are cut by chlorite-, epidote- and calcite-bearing veins. In turn, crosscutting relationship with the hydrothermal veins indicates pseudotachylytes were formed during this period of fluid activity. Rotary shear experiments conducted on bare surfaces of hydrothermally altered rocks at seismic slip velocities (3 m s-1) resulted in the production of vesiculated pseudotachylytes both at dry and water-pressurized conditions, with melt lubrication as the primary mechanism for fault dynamic weakening. The presented evidence challenges the common hypothesis that pseudotachylytes are limited to fluid-deficient environments, and gives insights into the ancient seismic activity of the system. Both field observations and experimental evidence, indicate that pseudotachylytes may easily be produced in hydrothermal environments, and could be a common co-seismic fault product. Consequently, melt lubrication could be considered one of the most efficient seismic dynamic weakening mechanisms in crystalline basement rocks of the continental crust.

Paleogenomics illuminates the evolutionary history of the extinct Holocene "horned" crocodile of Madagascar, Voay robustus

Ancient DNA is transforming our ability to reconstruct historical patterns and mechanisms shaping modern diversity and distributions. In particular, molecular data from extinct Holocene island faunas have revealed surprising biogeographic scenarios. Here, we recovered partial mitochondrial (mt) genomes for 1300-1400 year old specimens (n = 2) of the extinct "horned" crocodile, Voay robustus, collected from Holocene deposits in southwestern Madagascar. Phylogenetic analyses of partial mt genomes and tip-dated timetrees based on molecular, fossil, and stratigraphic data favor a sister group relationship between Voay and Crocodylus (true crocodiles). These well supported trees conflict with recent morphological systematic work that has consistently placed Voay within Osteolaeminae (dwarf crocodiles and kin) and provide evidence for likely homoplasy in crocodylian cranial anatomy and snout shape. The close relationship between Voay and Crocodylus lends additional context for understanding the biogeographic origins of these genera and refines competing hypotheses for the recent extinction of Voay from Madagascar.

Effectiveness of internet-based cognitive behavioural therapy for binge eating disorder

Introduction

Binge eating disorder (BED) is the most prevalent specific eating disorder. It is characterized by recurrent episodes of binge eating and is associated with feelings of shame and a lack of control. Internet-based treatments are gaining increasing attention as a way to reach more patients with evidence based treatments In 2020 we conducted a preliminary analysis on the effectiveness of an internet-based cognitive behavioural therapy treatment project (Jensen ES, Linnet, J, Holmberg TT, Tarp K, Nielsen JH, Lichtenstein MB. Effectiveness of internet-based guided self-help for binge-eating disorder and characteristics of completers versus noncompleters. Int J Eat Disord. 2020;1-6. https://doi.org/10.1002/eat.23384).

Objectives

This study aims to update the analyses on treatment effect with the patients who have completed treatment in the year following the last data extraction.

Methods

The iBED treatment project is a 10-session psychologist guided internet-based self-help program based on cognitive behavioural therapy. When applying for treatment and upon completion patients respond to a survey containing, among other scales, the eating disorder examination-questionnaire (EDE-Q), binge eating disorder-questionnaire (BED-Q) and various sociodemographic questions. Data will be extracted from the treatment project in anonymized form for analyses.

Results

The preliminary analyses were conducted on 36 completers. These showed large standardized effect sizes on both the EDE-Q subscales (Cohens d ranging from .88-1.65) and on the BED-Q (d = 1.38). The updated effectiveness analyses will be presented at the conference. We expect approximately 70-80 patients to have completed treatment at this time.

Conclusions

Results will be discussed and presented at the conference.

Patient motivations for seeking online therapy for binge eating disorder

Introduction

Binge Eating Disorder (BED) is characterized by repeatedly losing control over eating behavior and consuming large amounts of food within a short period of time. In later years, a growing body of evidence for effectiveness of internet-based Cognitive Behavioral Therapy (iCBT) as treatment for BED has emerged. Regarding the ability to complete a self-help program on the internet, internal self-regulation can be viewed as important.

Objectives

To qualitatively explore patient motivations for seeking therapy for BED according to intrinsic and extrinsic motivation as well as patient reasons for seeking online therapy.

Methods

The research design of this study was qualitatively. The participants were 52 adults suffering from mild to moderate BED. Data consisted of written texts entered by the participants into the online therapy program. The texts addressed the participants’ goals for their treatment course and their motives for seeking online therapy. The texts were analyzed by the means of systematic text condensation.

Results

Pertaining patient motivations for seeking therapy for BED, five main motivations that reached a saturated level in the sample were discovered: wish for control; avoidance of guilt/shame; desire for tools/insights; weight loss; and psychological stress. Participants ranged from one motivational factor to four, no participant had all the motivational factors. Regarding patient reasons for seeking online therapy, the following themes including sub themes were found: online treatment, treatment at home, and flexible treatment.

Conclusions

The results indicate that online therapy for BED may be able to breach some of the barriers there are towards treatment seeking.

Pre-Flight Calibration of the Mars 2020 Rover Mastcam Zoom (Mastcam-Z) Multispectral, Stereoscopic Imager

The NASA Perseverance rover Mast Camera Zoom (Mastcam-Z) system is a pair of zoomable, focusable, multi-spectral, and color charge-coupled device (CCD) cameras mounted on top of a 1.7 m Remote Sensing Mast, along with associated electronics and two calibration targets. The cameras contain identical optical assemblies that can range in focal length from 26 mm ( 25.5 ∘ × 19.1 ∘ FOV ) to 110 mm ( 6.2 ∘ × 4.2 ∘ FOV ) and will acquire data at pixel scales of 148-540 μm at a range of 2 m and 7.4-27 cm at 1 km. The cameras are mounted on the rover's mast with a stereo baseline of 24.3 ± 0.1  cm and a toe-in angle of 1.17 ± 0.03 ∘ (per camera). Each camera uses a Kodak KAI-2020 CCD with 1600 × 1200 active pixels and an 8 position filter wheel that contains an IR-cutoff filter for color imaging through the detectors' Bayer-pattern filters, a neutral density (ND) solar filter for imaging the sun, and 6 narrow-band geology filters (16 total filters). An associated Digital Electronics Assembly provides command data interfaces to the rover, 11-to-8 bit companding, and JPEG compression capabilities. Herein, we describe pre-flight calibration of the Mastcam-Z instrument and characterize its radiometric and geometric behavior. Between April 26 t h and May 9 t h , 2019, ∼45,000 images were acquired during stand-alone calibration at Malin Space Science Systems (MSSS) in San Diego, CA. Additional data were acquired during Assembly Test and Launch Operations (ATLO) at the Jet Propulsion Laboratory and Kennedy Space Center. Results of the radiometric calibration validate a 5% absolute radiometric accuracy when using camera state parameters investigated during testing. When observing using camera state parameters not interrogated during calibration (e.g., non-canonical zoom positions), we conservatively estimate the absolute uncertainty to be < 10 % . Image quality, measured via the amplitude of the Modulation Transfer Function (MTF) at Nyquist sampling (0.35 line pairs per pixel), shows MTF Nyquist = 0.26 - 0.50 across all zoom, focus, and filter positions, exceeding the > 0.2 design requirement. We discuss lessons learned from calibration and suggest tactical strategies that will optimize the quality of science data acquired during operation at Mars. While most results matched expectations, some surprises were discovered, such as a strong wavelength and temperature dependence on the radiometric coefficients and a scene-dependent dynamic component to the zero-exposure bias frames. Calibration results and derived accuracies were validated using a Geoboard target consisting of well-characterized geologic samples.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11214-021-00795-x.

The Mars 2020 Perseverance Rover Mast Camera Zoom (Mastcam-Z) Multispectral, Stereoscopic Imaging Investigation

Mastcam-Z is a multispectral, stereoscopic imaging investigation on the Mars 2020 mission's Perseverance rover. Mastcam-Z consists of a pair of focusable, 4:1 zoomable cameras that provide broadband red/green/blue and narrowband 400-1000 nm color imaging with fields of view from 25.6° × 19.2° (26 mm focal length at 283 μrad/pixel) to 6.2° × 4.6° (110 mm focal length at 67.4 μrad/pixel). The cameras can resolve (≥ 5 pixels) ∼0.7 mm features at 2 m and ∼3.3 cm features at 100 m distance. Mastcam-Z shares significant heritage with the Mastcam instruments on the Mars Science Laboratory Curiosity rover. Each Mastcam-Z camera consists of zoom, focus, and filter wheel mechanisms and a 1648 × 1214 pixel charge-coupled device detector and electronics. The two Mastcam-Z cameras are mounted with a 24.4 cm stereo baseline and 2.3° total toe-in on a camera plate ∼2 m above the surface on the rover's Remote Sensing Mast, which provides azimuth and elevation actuation. A separate digital electronics assembly inside the rover provides power, data processing and storage, and the interface to the rover computer. Primary and secondary Mastcam-Z calibration targets mounted on the rover top deck enable tactical reflectance calibration. Mastcam-Z multispectral, stereo, and panoramic images will be used to provide detailed morphology, topography, and geologic context along the rover's traverse; constrain mineralogic, photometric, and physical properties of surface materials; monitor and characterize atmospheric and astronomical phenomena; and document the rover's sample extraction and caching locations. Mastcam-Z images will also provide key engineering information to support sample selection and other rover driving and tool/instrument operations decisions.

Reducing psychiatric discharges to homelessness

In London, Ontario, discharges from psychiatric wards to shelters or NFA occurred 194 times per year. This discovery led to the creation of a pilot project that provided immediate access to a housing advocate and changed normal policies related to housing and start-up fees for a select group of income support recipients. The intervention was successful; seven participants who received this additional assistance were still housed six months later, whereas 6 of 7 who received usual care were still homeless. The goal of the current study was to determine the strengths and areas for improvement of a method to prevent discharge from hospital to NFA and suggest improvements in preparation for wider implementation.

Phase 2: intervention to all acute psychiatric patients within a general hospital.

Phase 3: intervention to all patients within a specialized tertiary care psychiatric hospital. Intervention included on-ward access to a housing advocate and income support staff which was facilitated through computer linkages to housing and income databases.

Findings revealed the success of the intervention across both acute and tertiary sites. All hypotheses were supported: the rate of discharge to homelessness decreased; those accessing the service were poor; and the cost savings from the program exceeded the cost of implementation. Advantages of the approach included: accessibility and convenience of services on site, positive influence on overall treatment plan and feelings of independence and support. Results reveal the positive influence a cross-sectoral approach has on preventing discharge from psychiatric wards to the streets and shelters.

Cultivation of C4 perennial energy grasses on heavy metal contaminated arable land: Impact on soil, biomass, and photosynthetic traits

The objective of this study was to evaluate the potential of three C4 perennial grasses (Miscanthus x giganteus, Panicum virgatum and Spartina pectinata) for biomass production on arable land unsuitable for food crop cultivation due to Pb, Cd and Zn contamination. We assessed soil properties, biomass yield, metal concentrations, and the photosynthetic performance of each species. Physico-chemical and elemental analyses were performed on soil samples before plantation establishment (2014) and after three years of cultivation (2016), when leaf area index, plant height, yield and heavy metal content of biomass were also determined. Physiological measurements (gas exchange, pigment content, chlorophyll a fluorescence) were recorded monthly between June and September on mature plants in 2016. Cultivation of investigated plants resulted in increased pH, nitrogen, and organic matter (OM) content in soil, although OM increase (13%) was significant only for S. pectinata plots. During the most productive months, maximal quantum yield values of primary photochemistry (F_v/F_m) and gas exchange parameter values reflected literature data of those plants grown on uncontaminated sites. Biomass yields of M. x giganteus (15.0 ± 0.4 t d.m. ha^-1) and S. pectinata (12.6 ± 1.2 t d.m. ha^-1) were also equivalent to data published from uncontaminated land. P. virgatum performed poorly (4.1 ± 0.4 t d.m. ha^-1), probably due to unfavourable climatic conditions, although metal uptake in this species was the highest (3.6 times that of M. x giganteus for Pb). Yield and physiological measurements indicated that M. x giganteus and S. pectinata were unaffected by the levels of contamination and therefore offer alternatives for areas where food production is prohibited. The broad cultivatable latitudinal range of these species suggests these results are widely relevant for development of the bioeconomy. We recommend multi-location trials under diverse contaminant and environmental regimes to determine the full potential of these species.

Five-year survival outcomes for patients with advanced melanoma treated with pembrolizumab in KEYNOTE-001

BACKGROUND

Pembrolizumab demonstrated robust antitumor activity and safety in the phase Ib KEYNOTE-001 study (NCT01295827) of advanced melanoma. Five-year outcomes in all patients and treatment-naive patients are reported herein. Patients whose disease progressed following initial response and who received a second course of pembrolizumab were also analyzed.

PATIENTS AND METHODS

Patients aged ≥18 years with previously treated or treatment-naive advanced/metastatic melanoma received pembrolizumab 2 mg/kg every 3 weeks, 10 mg/kg every 3 weeks, or 10 mg/kg every 2 weeks until disease progression, intolerable toxicity, or patient/investigator decision to withdraw. Kaplan-Meier estimates of overall survival (OS) and progression-free survival (PFS) were calculated. Objective response rate and PFS were based on immune-related response criteria by investigator assessment (data cut-off, September 1, 2017).

RESULTS

KEYNOTE-001 enrolled 655 patients with melanoma; median follow-up was 55 months. Estimated 5-year OS was 34% in all patients and 41% in treatment-naive patients; median OS was 23.8 months (95% CI, 20.2-30.4) and 38.6 months (95% CI, 27.2-not reached), respectively. Estimated 5-year PFS rates were 21% in all patients and 29% in treatment-naive patients; median PFS was 8.3 months (95% CI, 5.8-11.1) and 16.9 months (95% CI, 9.3-35.5), respectively. Median response duration was not reached; 73% of all responses and 82% of treatment-naive responses were ongoing at data cut-off; the longest response was ongoing at 66 months. Four patients [all with prior response of complete response (CR)] whose disease progressed during observation subsequently received second-course pembrolizumab. One patient each achieved CR and partial response (after data cut-off). Treatment-related AEs (TRAEs) occurred in 86% of patients and resulted in study discontinuation in 7.8%; 17% experienced grade 3/4 TRAE.

CONCLUSIONS

This 5-year analysis of KEYNOTE-001 represents the longest follow-up for pembrolizumab to date and confirms the durable antitumor activity and tolerability of pembrolizumab in advanced melanoma.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov, NCT01295827.

Gravity Wave Spectra in the Lower Stratosphere Diagnosed from Project Loon Balloon Trajectories

Project Loon has been launching super-pressure balloons since January 2013 to provide worldwide Internet coverage. These balloons typically fly between 18-21 km and provide measurements of winds and pressure fluctuations in the lower stratosphere. We divide 1,560 Loon flights into 3,405 two-day segments for gravity wave analysis. We derive the kinetic energy spectrum from the horizontal balloon motion and estimate the temperature perturbation spectrum (proportional to the potential energy spectrum) from the pressure variations. We fit the temperature (and kinetic energy) data to the functional form T , 2 = T O , 2 ( ω / ω O ) α where ω is the wave frequency, ω _o is daily frequency, T' _o is the base temperature amplitude and α is the slope. Both the kinetic energy and temperature spectra show -1.9±0.2 power-law dependence in the intrinsic frequency window 3 - 50 cycles/day. The temperature spectrum slope is weakly anti-correlated with the base temperature amplitude. We also find that the wave base temperature distribution is highly skewed. The average tropical modal temperature is 0.77 K. The highest amplitude waves occur over the mountainous regions, the tropics, and the high southern latitudes. Temperature amplitudes show little height variation over our 18-21 km domain. Our results are consistent with other limited super-pressure balloon analyses. The modal temperature is higher than the temperature currently used in Lagrangian model gravity wave parameterizations.

Exome Sequencing Identifies a Novel LMNA Splice-Site Mutation and Multigenic Heterozygosity of Potential Modifiers in a Family with Sick Sinus Syndrome, Dilated Cardiomyopathy, and Sudden Cardiac Death

The goals are to understand the primary genetic mechanisms that cause Sick Sinus Syndrome and to identify potential modifiers that may result in intrafamilial variability within a multigenerational family. The proband is a 63-year-old male with a family history of individuals (>10) with sinus node dysfunction, ventricular arrhythmia, cardiomyopathy, heart failure, and sudden death. We used exome sequencing of a single individual to identify a novel LMNA mutation and demonstrated the importance of Sanger validation and family studies when evaluating candidates. After initial single-gene studies were negative, we conducted exome sequencing for the proband which produced 9 gigabases of sequencing data. Bioinformatics analysis showed 94% of the reads mapped to the reference and identified 128,563 unique variants with 108,795 (85%) located in 16,319 genes of 19,056 target genes. We discovered multiple variants in known arrhythmia, cardiomyopathy, or ion channel associated genes that may serve as potential modifiers in disease expression. To identify candidate mutations, we focused on ~2,000 variants located in 237 genes of 283 known arrhythmia, cardiomyopathy, or ion channel associated genes. We filtered the candidates to 41 variants in 33 genes using zygosity, protein impact, database searches, and clinical association. Only 21 of 41 (51%) variants were validated by Sanger sequencing. We selected nine confirmed variants with minor allele frequencies <1% for family studies. The results identified LMNA c.357-2A>G, a novel heterozygous splice-site mutation as the primary mutation with rare or novel variants in HCN4, MYBPC3, PKP4, TMPO, TTN, DMPK and KCNJ10 as potential modifiers and a mechanism consistent with haploinsufficiency.

Measurement of the Target-Normal Single-Spin Asymmetry in Quasielastic Scattering from the Reaction (3)He(↑)(e,e')

We report the first measurement of the target single-spin asymmetry, A(y), in quasielastic scattering from the inclusive reaction (3)He(↑)(e,e') on a (3)He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero A(y) can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q(2)=0.13, 0.46, and 0.97  GeV(2). These measurements demonstrate, for the first time, that the (3)He asymmetry is clearly nonzero and negative at the 4σ-9σ level. Using measured proton-to-(3)He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1-3)% were obtained. The neutron asymmetry at high Q(2) is related to moments of the generalized parton distributions (GPDs). Our measured neutron asymmetry at Q(2)=0.97  GeV(2) agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions.

Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton

Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θ_{cm}^{p}=70°. The longitudinal transfer K_{LL}, measured to be 0.645±0.059±0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ~3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

Measurement of double-polarization asymmetries in the quasielastic (3)He[→](e[→],e(')d) process

We present a precise measurement of double-polarization asymmetries in the ^{3}He[over →](e[over →],e^{'}d) reaction. This particular process is a uniquely sensitive probe of hadron dynamics in ^{3}He and the structure of the underlying electromagnetic currents. The measurements have been performed in and around quasielastic kinematics at Q^{2}=0.25(GeV/c)^{2} for missing momenta up to 270  MeV/c. The asymmetries are in fair agreement with the state-of-the-art calculations in terms of their functional dependencies on p_{m} and ω, but are systematically offset. Beyond the region of the quasielastic peak, the discrepancies become even more pronounced. Thus, our measurements have been able to reveal deficiencies in the most sophisticated calculations of the three-body nuclear system, and indicate that further refinement in the treatment of their two-and/or three-body dynamics is required.

Endurance training is feasible in severely disabled patients with progressive multiple sclerosis

This study tested whether upper-body endurance training (ET) is feasible and can be performed at sufficient intensity to induce cardiovascular adaptations in severely disabled patients with progressive multiple sclerosis (MS). Eleven progressive MS patients (6.5 ≤ EDSS ≤ 8.0) scheduled for a four-week inpatient rehabilitation program were randomized to a control group (CON, n = 5) that received standard individualized MS rehabilitation or an intervention group (EXE, n = 6) that in addition received 10 sessions of predominantly upper-body ET. One patient dropped out of the EXE group (drop-out rate: 1/6~17%) and no adverse events were recorded. The EXE group completed on average 9.3±0.8 sessions (~96.0±5%). During the ET sessions an average heart rate of 93.9±9.3beats*min(-1) were sustained corresponding to 91.6±6.8% of the maximal pre-intervention heart rate. In the EXE group a trend toward a time*group interaction was seen for VO2peak (p = 0.06). ET is feasible in severely disabled patients with progressive MS and it can probably be performed at sufficient intensity to induce cardiovascular adaptations.

Integrating an evidence-based intervention into clinical practice: 'transitional relationship model'

The transitional relationship model (TRM) facilitates the discharge process by providing peer support and hospital staff involvement until a therapeutic relationship has been established with a community care provider. A quasi-experimental, action-oriented research design was employed in which psychiatric wards at six hospital sites implemented the model in three waves. Helpful strategies were identified by each wave of wards for consideration by subsequent wards. Using an ethnographic approach, qualitative data were examined to uncover experiences and perceptions of TRM implementation and to help identify key issues that were supporting or hampering implementation. Specific strategies that facilitate the implementation of TRM include: (1) the use of educational modules for on-ward hospital staff training and peer training; (2) presence of on-site champions; and (3) supportive documentation systems. Issues identified as barriers to implementation included: (1) feeling drowned, swamped and overwhelmed; (2) death by process; (3) team dynamics; and (4) changes in champions. Staged large-scale implementation of the TRM allowed for iterative improvements to the model leading to positive outcomes. This study highlights the need to address work environment issues, particularly interprofessional teams.