Cognitive function in people with and without freezing of gait in Parkinson’s disease

Freezing of gait (FOG) is common in people with Parkinson’s disease (PD) which is extremely debilitating. One hypothesis for the cause of FOG episodes is impaired cognitive control, however, this is still in debate in the literature. We aimed to assess a comprehensive range of cognitive tests in older adults and people with Parkinson’s with and without FOG and associate FOG severity with cognitive performance. A total of 227 participants took part in the study which included 80 healthy older adults, 81 people with PD who did not have FOG and 66 people with PD and FOG. A comprehensive battery of neuropsychological assessments tested cognitive domains of global cognition, executive function/attention, working memory, and visuospatial function. The severity of FOG was assessed using the new FOG questionnaire and an objective FOG severity score. Cognitive performance was compared between groups using an ANCOVA adjusting for age, gender, years of education and disease severity. Correlations between cognitive performance and FOG severity were analyzed using partial correlations. Cognitive differences were observed between older adults and PD for domains of global cognition, executive function/attention, and working memory. Between those with and without FOG, there were differences for global cognition and executive function/attention, but these differences disappeared when adjusting for covariates. There were no associations between FOG severity and cognitive performance. This study identified no significant difference in cognition between those with and without FOG when adjusting for covariates, particularly disease severity. This may demonstrate that complex rehabilitation programs may be undertaken in those with FOG

Older adults can improve compensatory stepping with repeated postural perturbations

The ability to respond quickly and accurately to an external perturbation with a stepping response is critical to avoid falls and this ability is impaired in older, compared to young adults. However, little is known about whether young and older adults improve compensatory stepping responses similarly with practice. This study compares the extent to which young and older adults can improve, retain, and generalize postural compensatory steps in response to external perturbations. Centre of mass displacement, step characteristics and lower leg muscle activation latencies were measured during one training session of compensatory stepping in response to large surface translations in 13 young and 12 older adults. Retention was tested 24 h later. Older adults decreased their center of mass displacements over repeated exposure to large surface translations in both the anterior and posterior directions and retained these improvements. In contrast, young adults only showed adaptation and retention of forward stepping responses. Neither group was able to generalize improvements in stepping responses across directions. These results suggest step training may be beneficial for older adults, however additional, multidirectional training may be necessary to facilitate generalization of postural stepping responses for any direction of a slip or trip

Comparative Toxicity of Diphacinone to Northern Bobwhite (\u3ci\u3eColinus virginianus\u3c/i\u3e) and American Kestrels (\u3ci\u3eFalco sparverius\u3c/i\u3e)

The acute oral toxicity of the anticoagulant rodenticide diphacinone was found to be about 20 times greater to American kestrels (LD50=97 mg/kg) than to northern bobwhite (LD50=2,014 mg/kg). Several precise and sensitive clotting assays (prothrombin time, Russell’s Viper venom time, thrombin clotting time) were adapted for use in these species, and this combination of assays is recommended to detect effects of diphacinone and other rodenticides on coagulation. Oral administration of diphacinone over a range of doses (sublethal to the extrapolated LD15) prolonged prothrombin time and Russell’s Viper venom time within 24 to 48 hrs post-exposure. Prolongation of in vitro clotting time reflects impaired coagulation complex activity and was detected before or at the onset of overt signs of toxicity and lethality. These data will assist in the development of a pharmacodynamic model to assess and predict rodenticide toxicity to non-target avian species

Comparative Toxicity of Diphacinone to Northern Bobwhite (\u3ci\u3eColinus virginianus\u3c/i\u3e) and American Kestrels (\u3ci\u3eFalco sparverius\u3c/i\u3e)

The acute oral toxicity of the anticoagulant rodenticide diphacinone was found to be about 20 times greater to American kestrels (LD50=97 mg/kg) than to northern bobwhite (LD50=2,014 mg/kg). Several precise and sensitive clotting assays (prothrombin time, Russell’s Viper venom time, thrombin clotting time) were adapted for use in these species, and this combination of assays is recommended to detect effects of diphacinone and other rodenticides on coagulation. Oral administration of diphacinone over a range of doses (sublethal to the extrapolated LD15) prolonged prothrombin time and Russell’s Viper venom time within 24 to 48 hrs post-exposure. Prolongation of in vitro clotting time reflects impaired coagulation complex activity and was detected before or at the onset of overt signs of toxicity and lethality. These data will assist in the development of a pharmacodynamic model to assess and predict rodenticide toxicity to non-target avian species

The use of dopamine-hyaluronate associate-coated maghemite nanoparticles to label cells

Sodium hyaluronate (HA) was associated with dopamine (DPA) and introduced as a coating for maghemite (γ-Fe2O3) nanoparticles obtained by the coprecipitation of iron(II) and iron(III) chlorides and oxidation with sodium hypochlorite. The effects of the DPA anchorage of HA on the γ-Fe2O3 surface on the physicochemical properties of the resulting colloids were investigated. Nanoparticles coated at three different DPA-HA/γ-Fe2O3 and DPA/HA ratios were chosen for experiments with rat bone marrow mesenchymal stem cells and human chondrocytes. The nanoparticles were internalized into rat bone marrow mesenchymal stem cells via endocytosis as confirmed by Prussian Blue staining. The efficiency of mesenchymal stem cell labeling was analyzed. From among the investigated samples, efficient cell labeling was achieved by using DPA-HA-γ-Fe2O3 nanoparticles with DPA-HA/γ-Fe2O3 = 0.45 (weight/ weight) and DPA/HA = 0.038 (weight/weight) ratios. The particles were used as a contrast agent in magnetic resonance imaging for the labeling and visualization of cells

Towards Phytoplankton Parasite Detection Using Autoencoders

Phytoplankton parasites are largely understudied microbial components with a potentially significant ecological impact on phytoplankton bloom dynamics. To better understand their impact, we need improved detection methods to integrate phytoplankton parasite interactions in monitoring aquatic ecosystems. Automated imaging devices usually produce high amount of phytoplankton image data, while the occurrence of anomalous phytoplankton data is rare. Thus, we propose an unsupervised anomaly detection system based on the similarity of the original and autoencoder-reconstructed samples. With this approach, we were able to reach an overall F1 score of 0.75 in nine phytoplankton species, which could be further improved by species-specific fine-tuning. The proposed unsupervised approach was further compared with the supervised Faster R-CNN based object detector. With this supervised approach and the model trained on plankton species and anomalies, we were able to reach the highest F1 score of 0.86. However, the unsupervised approach is expected to be more universal as it can detect also unknown anomalies and it does not require any annotated anomalous data that may not be always available in sufficient quantities. Although other studies have dealt with plankton anomaly detection in terms of non-plankton particles, or air bubble detection, our paper is according to our best knowledge the first one which focuses on automated anomaly detection considering putative phytoplankton parasites or infections

Validation of the Human Activity Profile Questionnaire in Patients after Allogeneic Hematopoietic Stem Cell Transplantation

Chronic graft-versus-host disease (cGVHD) associated morbidity and mortality remain major barriers for successful allogeneic hematopoietic stem cell transplantation (alloHSCT). Currently, no reliable measures are established to monitor cGVHD activity changes for use in clinical trials. The Human Activity Profile (HAP) patient self-report was proposed by the National Institutes of Health (NIH) cGVHD consensus project as an independent measure of patients' functional status that could also indirectly reflect improvement of cGVHD, but that has not been validated in an alloHSCT patient population. One hundred seventy-six patients (median age 44 years [range: 18-72 years] after alloHSCT were evaluated with a German translation of the HAP, the NIH criteria-based cGVHD activity assessment, the Lee cGVHD Symptom-Scale, FACT-BMT, SF36, Berlin Social Support Scale, 24-Item Adjective Measure (24-AM), Hospital Anxiety and Depression Scale, and the NCCN-Distress-Thermometer. Enrollment occurred a median of 286 (range: 85-4003) days after alloHSCT. Follow-up surveys were conducted at 1, 2, 3, 5, 8, and 12 months after the baseline survey. Although 117 patient had cGVHD at time of enrollment (mild n = 33, moderate n = 50, or severe n = 34), 59 patients were included into the study in the absence of cGVHD between days 85 and 395 after transplantation. The maximum activity score (MAS) and adjusted activity score (AAS) of the HAP correlated inversely with grading of cGVHD severity (mild, moderate, or severe) (r = −0.25 for MAS and −0.24 for AAS). Lung manifestations of cGVHD correlated with AAS (r = 0.17), but not with MAS. HAP scores correlated with subscales from other instruments measuring physical domains, especially the physical functioning scale of the SF36. Performance was improved by use of an HSCT-modified HAP scoring system that excluded activities prohibited within the first year after alloHSCT. No significant correlation of the HAP was found with personality, age, sex, symptom burden, or social functioning or social well-being. Moreover, the HAP displayed a higher sensitivity to change of cGVHD activity compared to the SF36 and the FACT-BMT. In addition, steroid myopathy correlated with both HAP scores, but not the SF36. The HAP is a simple and valid questionnaire for the evaluation of the physical activity in patients after alloHSCT, with the advantage of detecting changes in cGVHD status independently of other quality-of-life measures and with a superior sensitivity compared to the SF36

Relating Parkinson freezing and balance domains: A structural equation modeling approach

Background: People with PD who exhibit freezing of gait (FOG) also exhibit poor balance compared to those who do not freeze. However, balance is a broad construct that can be subdivided into subdomains that include dynamic balance (gait), anticipatory postural adjustments (APAs) & gait initiation, postural sway in stance, and automatic postural responses (e.g., reactive stepping). Few studies have provided a robust investigation on how each of these domains is impacted by FOG, and no studies have compared balance across groups while rigorously controlling for disease severity. Methods: Structural equation modeling was used to evaluate the relationships between FOG and balance domains constructed as latent variables and controlling for disease severity. Domains included: dynamic balance (gait), APAs, postural sway, and reactive stepping. Models were run relating domains to both the presence and severity of FOG. Results: Latent variables reflecting domains of Gait and APAs, but not postural sway or reactive stepping, were significantly related to the severity of FOG. Models for presence of FOG showed the same results, as Gait and APAs, but not postural sway or reactive stepping, were related to presence of FOG. Conclusion: These results are consistent with hypotheses that balance deficits in people with PD who freeze are most pronounced in gait and anticipatory postural adjustments. Reactive stepping and postural sway domains are less effected in PD patients who freeze compared to those who do not. These findings suggest that rehabilitative strategies focused on gait and APAs may be most effective for people with PD who freeze

Quasi-2D anomalous Hall Mott insulator of topologically engineered Jeff =1/2 electrons

We investigate an experimental toy-model system of a pseudospin-half square-lattice Hubbard Hamiltonian in [(SrIrO3)1/(CaTiO3)1] to include both nontrivial complex hopping and moderate electronic correlation. While the former induces electronic Berry phases as anticipated from the weak-coupling limit, the later stabilizes an antiferromagnetic (AFM) Mott insulator ground state in analogous to the strong-coupling limit. Their combined results in the real system are found to be an anomalous Hall effect with a non-monotonic temperature dependence due to the self-competition of the electron-hole pairing in the Mott state, and an exceptionally large Ising anisotropy that is captured as a giant magnon gap beyond the superexchange approach. The unusual phenomena highlight the rich interplay of electronic topology and electronic correlation in the intermediate-coupling regime that is largely unexplored and challenging in theoretical modelling.Comment: Accepted by Phys. Rev.