High-to-low CO2 acclimation reveals plasticity of the photorespiratory pathway and indicates regulatory links to cellular metabolism of Arabidopsis

Background: Photorespiratory carbon metabolism was long considered as an essentially closed and nonregulated pathway with little interaction to other metabolic routes except nitrogen metabolism and respiration. Most mutants of this pathway cannot survive in ambient air and require CO 2-enriched air for normal growth. Several studies indicate that this CO 2 requirement is very different for individual mutants, suggesting a higher plasticity and more interaction of photorespiratory metabolism as generally thought. To understand this better, we examined a variety of high- and low-level parameters at 1% CO 2 and their alteration during acclimation of wild-type plants and selected photorespiratory mutants to ambient air. Methodology and Principal Findings: The wild type and four photorespiratory mutants of Arabidopsis thaliana (Arabidopsis) were grown to a defined stadium at 1% CO 2 and then transferred to normal air (0.038% CO 2). All other conditions remained unchanged. This approach allowed unbiased side-by-side monitoring of acclimation processes on several levels. For all lines, diel (24 h) leaf growth, photosynthetic gas exchange, and PSII fluorescence were monitored. Metabolite profiling was performed for the wild type and two mutants. During acclimation, considerable variation between the individual genotypes was detected in many of the examined parameters, which correlated with the position of the impaired reaction in the photorespiratory pathway. Conclusions: Photorespiratory carbon metabolism does not operate as a fully closed pathway. Acclimation from high to low CO 2 was typically steady and consistent for a number of features over several days, but we also found unexpected short-term events, such as an intermittent very massive rise of glycine levels after transition of one particular mutant to ambient air. We conclude that photorespiration is possibly exposed to redox regulation beyond known substrate-level effects. Additionally, our data support the view that 2-phosphoglycolate could be a key regulator of photosynthetic-photorespiratory metabolism as a whole. © 2012 Timm et al

Robust and scalable rf spectroscopy in first-order magnetic sensitive states at second-long coherence time

Trapped-ion quantum sensors have become highly sensitive tools for the search of physics beyond the Standard Model. Recently, stringent tests of local Lorentz-invariance (LLI) have been conducted with precision spectroscopy in trapped ions. We here elaborate on robust and scalable radio-frequency composite-pulse spectroscopy at second long coherence times in the magnetic sublevels of the long-lived $^{2}F_{7/2}$ state of a trapped $^{172}$Yb$^{+}$ ion. We compare two Ramsey-type composite rf pulse sequences, a generalized spin-echo (GSE) sequence and a sequence based on universal rotations with 10 rephasing pulses (UR10) that decouple the energy levels from magnetic field noise, enabling robust and accurate spectroscopy. Both sequences are characterized theoretically and experimentally in the spin-$1/2$$\ $$^{2}S_{1/2}$electronic ground state of$^{172}$Yb$^{+}$and results show that the UR10 sequence is 38 (13) times more robust against pulse duration (frequency detuning) errors than the GSE sequence. We extend our simulations to the eight-level manifold of the$^2F_{7/2}$state, which is highly sensitive to a possible violation of LLI, and show that the UR10 sequence can be used for high-fidelity Ramsey spectroscopy in noisy environments. The UR10 sequence is implemented experimentally in the$^2F_{7/2}$manifold and a coherent signal of up to$2.5\,$s is reached. We have implemented the sequence and used it to perform the most stringent test of LLI in the electron-photon sector to date. Due to the robustness of the UR10 sequence, it can be applied on larger ion crystals to improve tests of Lorentz symmetry further. We demonstrate that the sequence can also be used to extract the quadrupole moment of the meta-stable$^{2}F_{7/2}$state, obtaining a value of$\Theta\,=\,-0.0298(38)\,ea^{2}_{0}$ which is in agreement with the value deduced from clock measurements.Comment: 19 pages, 7 figure

The auditory startle response in relation to outcome in functional movement disorders

Background: The auditory startle reflex (ASR) is enlarged in patients with functional movement disorders (FMD). Objectives: To study whether the ASR relates to symptom reduction in FMD patients, who participated in a placebo controlled double blind treatment trial with Botulinum Neurotoxin (BoNT). Methods: Response to treatment in the BoNT study was assessed using the Clinical Global Impression - Improvement scale (CGI-I). The electromyography (EMG) muscle activity of 7 muscles following 110 dB tones was measured in 14 FMD patients before and after one-year treatment and compared to 11 matched controls. The early and a late (behaviorally affected) component of the ASR and the sympathetic skin response (SSR) were assessed. Results: 10 of 14 patients (71.4%) showed symptom improvement, which was believed to be mainly caused by placebo effects. The early total response probability of the ASR at baseline tended to be larger in patients compared to controls (p = 0.08), but normalized at follow-up (p = 0.84). The late total response probability was larger in patients vs. controls at baseline (p < 0.05), a trend that still was present at follow-up (p = 0.08). The SSR was higher in patients vs. controls at baseline (p < 0.01), and normalized at follow-up (p = 0.71). Conclusions: On a group level 71.4% of the patients showed clinical symptom improvement after treatment. The early part of the ASR, most likely reflecting anxiety and hyperarousal, normalized in line with the clinical improvement. Interestingly, the augmented late component of the ASR remained enlarged suggesting persistent altered behavioral processing in functional patients despite motor improvement

Motional heating of spatially extended ion crystals

We study heating of motional modes of a single ion and of extended ion crystals trapped in a linear radio frequency (rf) Paul trap with a precision of Δ ṅ ≈ 0.1 phonons s-1. Single-ion axial and radial heating rates are consistent and electric field noise has been stable over the course of four years. At a secular frequency of ω sec = 2π × 620 kHz, we measure ṅ = 0.56 (6) phonons s-1 per ion for the center-of-mass (com) mode of linear chains of up to 11 ions and observe no significant heating of the out-of-phase (oop) modes. By displacing the ions away from the nodal line, inducing excess micromotion, rf noise heats the com mode quadratically as a function of radial displacement r by phonons s-1 μm-2 per ion, while the oop modes are protected from rf-noise induced heating in linear chains. By changing the quality factor of the resonant rf circuit from Q = 542 to Q = 204, we observe an increase of rf noise by a factor of up to 3. We show that the rf-noise induced heating of motional modes of extended crystals also depends on the symmetry of the crystal and of the mode itself. As an example, we consider several 2D and 3D crystal configurations. Heating rates of up to 500 ph s-1 are observed for individual modes, giving rise to a total kinetic energy increase and thus a fractional time dilation shift of up to -0.3 × 10-18 s-1 of the total system. In addition, we detail how the excitation probability of the individual ions is reduced and decoherence is increased due to the Debye-Waller effect

Coherent Excitation of the Highly Forbidden Electric Octupole Transition in Yb+ 172

We report on the first coherent excitation of the highly forbidden S21/2?F27/2 electric octupole (E3) transition in a single trapped Yb+172 ion, an isotope without nuclear spin. Using the transition in Yb+171 as a reference, we determine the transition frequency to be 642 116 784 950 887.6(2.4) Hz. We map out the magnetic field environment using the forbidden S21/2?D25/2 electric quadrupole (E2) transition and determine its frequency to be 729 476 867 027 206.8(4.4) Hz. Our results are a factor of 1×105 (3×105) more accurate for the E2 (E3) transition compared to previous measurements. The results open up the way to search for new physics via precise isotope shift measurements and improved tests of local Lorentz invariance using the metastable F27/2 state of Yb+. © 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI

The chronnectome as a model for Charcot's 'dynamic lesion' in functional movement disorders

This exploratory study set out to investigate dynamic functional connectivity (dFC) in patients with jerky and tremulous functional movement disorders (JT-FMD). The focus in this work is on dynamic brain states, which represent distinct dFC patterns that reoccur in time and across subjects. Resting-state fMRI data were collected from 17 patients with JT-FMD and 17 healthy controls (HC). Symptom severity was measured using the Clinical Global Impression-Severity scale. Depression and anxiety were measured using the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI), respectively. Independent component analysis was used to extract functional brain components. After computing dFC, dynamic brain states were determined for every subject using k-means clustering. Compared to HC, patients with JT-FMD spent more time in a state that was characterized predominantly by increasing medial prefrontal, and decreasing posterior midline connectivity over time. They also tended to visit this state more frequently. In addition, patients with JT-FMD transitioned significantly more often between different states compared to HC, and incorporated a state with decreasing medial prefrontal, and increasing posterior midline connectivity in their attractor, i.e., the cyclic patterns of state transitions. Altogether, this is the first study that demonstrates altered functional brain network dynamics in JT-FMD that may support concepts of increased self-reflective processes and impaired sense of agency as driving factors in FMD

Internal medicine residency training for unhealthy alcohol and other drug use: recommendations for curriculum design

<p>Abstract</p> <p>Background</p> <p>Unhealthy substance use is the spectrum from use that risks harm, to use associated with problems, to the diagnosable conditions of substance abuse and dependence, often referred to as substance abuse disorders. Despite the prevalence and impact of unhealthy substance use, medical education in this area remains lacking, not providing physicians with the necessary expertise to effectively address one of the most common and costly health conditions. Medical educators have begun to address the need for physician training in unhealthy substance use, and formal curricula have been developed and evaluated, though broad integration into busy residency curricula remains a challenge.</p> <p>Discussion</p> <p>We review the development of unhealthy substance use related competencies, and describe a curriculum in unhealthy substance use that integrates these competencies into internal medicine resident physician training. We outline strategies to facilitate adoption of such curricula by the residency programs. This paper provides an outline for the actual implementation of the curriculum within the structure of a training program, with examples using common teaching venues. We describe and link the content to the core competencies mandated by the Accreditation Council for Graduate Medical Education, the formal accrediting body for residency training programs in the United States. Specific topics are recommended, with suggestions on how to integrate such teaching into existing internal medicine residency training program curricula.</p> <p>Summary</p> <p>Given the burden of disease and effective interventions available that can be delivered by internal medicine physicians, teaching about unhealthy substance use must be incorporated into internal medicine residency training, and can be done within existing teaching venues.</p

Distribution and Coexistence of Myoclonus and Dystonia as Clinical Predictors of SGCE Mutation Status: A Pilot Study

Neurological Motor Disorder

Startle responses in functional jerky movement disorders are increased but have a normal pattern

Background: Exaggerated startle reactions have been frequently described in patients with functional movement disorders (FMD). Long onset latencies and inconsistent recruitment pattern are thought to be a hallmark in these patients. The auditory startle reflex has not been systematically assessed though. Objectives: Assessing the frequency and pattern of the early and late component of the auditory startle response in patients with functional jerky movement disorders. Methods: A case-control design was used to study 17 patients with functional jerky movement disorders and 15 healthy gender- and age-matched control subjects. The auditory startle reflex was elicited by 108 dB loud tones and assessed with electromyography in multiple muscles. Results: Response probability of the early and the late response were significantly enlarged in patients with FMD. The early response showed a normal muscle recruitment pattern whereas the late response revealed a more variable pattern compared to controls. The early and late responses showed normal habituation in both groups. Remarkably, a high response rate of the abdominal muscle was noted especially in patients suffering from abdominal jerks. Conclusions: This study shows enlarged, but normally patterned early startle responses in FMD. The high response frequency of the late responses found in these patients reflects a behavioral component. Hypersensitivity to external stimuli, often noted in FMD is supported by high response probabilities of both components of the auditory startle response. (C) 2017 Elsevier Ltd. All rights reserve