1,990 research outputs found

    Dzyaloshinskii-Moriya interaction and Hall effects in the skyrmion phase of MnFeGe alloys

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    We carry out density functional theory calculations which demonstrate that the electron dynamics in the skyrmion phase of Fe-rich Mn1x_{1-x}Fex_xGe alloys is governed by Berry phase physics. We observe that the magnitude of the Dzyaloshinskii-Moriya interaction, directly related to the mixed space-momentum Berry phases, changes sign and magnitude with concentration xx in direct correlation with the data of Shibata {\it et al.}, Nature Nanotech. {\bf 8}, 723 (2013). The computed anomalous and topological Hall effects in FeGe are also in good agreement with available experiments. We further develop a simple tight-binding model able to explain these findings. Finally, we show that the adiabatic Berry phase picture is violated in the Mn-rich limit of the alloys.Comment: 5 page

    Investigating the Minimal Counterintuitiveness Effect

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    Scholars believe that minimally counterintuitive concepts are more memorable than intuitive ones (Barrett, 2008; Upal 2011). If an item has an unusual or counterintuitive property, such as a ball that rises rather than falls when dropped, the unusual property makes the item more memorable. However, experiments investigating this effect tend to have experimental confounds that make interpretation difficult. Our experiment aimed to solve these problems by using counterbalanced lists of nonwords, using the nonwords to control for prior associations and experiences. Participants viewed a series of nonwords along with a noun-adjective pair (e.g. Frav – a roaring tiger) and were told that each nonword represented a name. Some nonwords were the names of an intuitive item (e.g. a roaring tiger) whereas others were counterintuitive (e.g. a writing tiger). Participants rated the likelihood that the described nonword was from Earth or from a parallel universe where things were different. Everyone was told to remember the nonwords and noun-adjective pairs for a later test. To improve overall recall, each item was presented and rated twice. After a distractor, participants were asked to recall as many of the nonwords as possible. The results revealed that counterintuitive items were not better-recalled than intuitive items. In fact, in most tests, intuitive items were recalled significantly more often than intuitive items. Our results do not support the Minimal Counterintuitiveness Effect and suggest that when to-be-remembered words and their accompanying nouns are matched across conditions (counterintuitive and intuitive), that intuitive information is more memorable than counterintuitive information

    Metagenomics approaches for the detection and surveillance of emerging and recurrent plant pathogens

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    Globalization has a dramatic effect on the trade and movement of seeds, fruits and vegetables, with a corresponding increase in economic losses caused by the introduction of transboundary plant pathogens. Current diagnostic techniques provide a useful and precise tool to enact surveillance protocols regarding specific organisms, but this approach is strictly targeted, while metabarcoding and shotgun metagenomics could be used to simultaneously detect all known pathogens and potentially new ones. This review aims to present the current status of high-throughput sequencing (HTS) diagnostics of fungal and bacterial plant pathogens, discuss the challenges that need to be addressed, and provide direction for the development of methods for the detection of a restricted number of related taxa (specific surveillance) or all of the microorganisms present in a sample (general surveillance). HTS techniques, particularly metabarcoding, could be useful for the surveillance of soilborne, seedborne and airborne pathogens, as well as for identifying new pathogens and determining the origin of outbreaks. Metabarcoding and shotgun metagenomics still suffer from low precision, but this issue can be limited by carefully choosing primers and bioinformatic algorithms. Advances in bioinformatics will greatly accelerate the use of metagenomics to address critical aspects related to the detection and surveillance of plant pathogens in plant material and foodstuffs

    Potential roads for reaching the summit: an overview on target therapies for high-grade gliomas

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    Background: The tailored targeting of specific oncogenes represents a new frontier in the treatment of high-grade glioma in the pursuit of innovative and personalized approaches. The present study consists in a wide-ranging overview of the target therapies and related translational challenges in neuro-oncology. Methods: A review of the literature on PubMed/MEDLINE on recent advances concerning the target therapies for treatment of central nervous system malignancies was carried out. In the Medical Subject Headings, the terms “Target Therapy”, “Target drug” and “Tailored Therapy” were combined with the terms “High-grade gliomas”, “Malignant brain tumor” and “Glioblastoma”. Articles published in the last five years were further sorted, based on the best match and relevance. The ClinicalTrials.gov website was used as a source of the main trials, where the search terms were “Central Nervous System Tumor”, “Malignant Brain Tumor”, “Brain Cancer”, “Brain Neoplasms” and “High-grade gliomas”. Results: A total of 137 relevant articles and 79 trials were selected. Target therapies entailed inhibitors of tyrosine kinases, PI3K/AKT/mTOR pathway, farnesyl transferase enzymes, p53 and pRB proteins, isocitrate dehydrogenases, histone deacetylases, integrins and proteasome complexes. The clinical trials mostly involved combined approaches. They were phase I, II, I/II and III in 33%, 42%, 16%, and 9% of the cases, respectively. Conclusion: Tyrosine kinase and angiogenesis inhibitors, in combination with standard of care, have shown most evidence of the effectiveness in glioblas-toma. Resistance remains an issue. A deeper understanding of the molecular pathways involved in gliomagen-esis is the key aspect on which the translational research is focusing, in order to optimize the target therapies of newly diagnosed and recurrent brain gliomas. (www.actabiomedica.it)

    Piezoelectric coupling as a feature sensitive to structural alterations

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    The paper presents an exploratory study about the use of electro-mechanical coupling measurements as a feature for detecting structural alterations using piezoelectric transducers. This coupling between the piezoelectric transducers and the structure can be estimated by means of low frequency vibration measurements and will prove to be a feature sensitive to structure alterations and scarcely influenced by temperature variations. Moreover, the approach proposed is designed such that it can also employ piezoelectric elements already available in the system for other purposes (e.g., vibration control), thus not requiring any additional expensive device, and can work while the system to be monitored is operating. The paper introduces at first the principle of the method and shows how to improve its accuracy by connecting the piezoelectric transducers with proper electric impedances. Then, numerical simulations and experimental results are presented to prove the feasibility of the proposed approach

    Oleogelation of extra virgin olive oil by different gelators affects lipid digestion and polyphenol bioaccessibility

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    The possibility to steer extra virgin olive oil (EVOO) digestion and polyphenol bioaccessibility through oleogelation was investigated. EVOO was converted into oleogels using lipophilic (monoglycerides, rice wax, sunflower wax, phytosterols) or hydrophilic (whey protein aerogel particles, WP) gelators. In-vitro digestion demonstrated that the oleogelator nature influenced both lipid digestion and polyphenol bioaccessibility. WP-based oleogels presented ∼100% free fatty acid release compared to ∼64% for unstructured EVOO and ∼40 to ∼55% for lipophilic-based oleogels. This behavior was attributed to the ability of WP to promote micelle formation through oleogel destructuring. Contrarily, the lower lipolysis of EVOO gelled with lipophilic gelators compared to unstructured EVOO suggested that the gelator obstructed lipase accessibility. Tyrosol and hydroxytyrosol bioaccessibility increased for WP oleogels (∼27%), while liposoluble-based oleogels reduced it by 7 to 13%. These findings highlight the deep effect of the gelator choice on the digestion fate of EVOO components in the human body

    Cardiovascular and metabolic responses during indoor climbing and laboratory cycling exercise in advanced and élite climbers

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    Purpose. To validate heart rate (fH) as an effective indicator of the aerobic demands of climbing, the fH vs. oxygen uptake (VO2) relationship determined during cycling exercise and climbing on a circular climbing treadwall was compared. Possible differences in maximum aerobic characteristics between advanced and \ue9lite climbers were also assessed. Methods. Seven advanced and six \ue9lite climbers performed a discontinuous incremental test on a cycle ergometer and a similar test on a climbing treadwall. Cardiorespiratory and gas exchange parameters were collected at rest and during exercise. Results. The fH vs. VO2 relationship was steeper during cycling than climbing at submaximal exercise for both groups and during climbing in the \ue9lite climbers as compared to the advanced. At peak exercise, VO2 was similar during both cycling and climbing (3332\ub1115 and 3193\ub1129 ml/min, respectively). Despite similar VO2 peak, the \ue9lite climbers had a higher peak workload during climbing (11.8\ub10.8 vs. 9.2\ub10.3 m/min in \ue9lite and advanced climbers, respectively; P=.024) but not during cycling (282\ub113 vs. 268\ub112 W in \ue9lite and advanced climbers, respectively). Conclusions. Our findings indicate that care should be taken when energy expenditure during climbing is estimated from the fH vs VO2 relationship determined in the laboratory. The level of climbing experience significantly affects the energy cost of exercise. Lastly, the similar aerobic demands of cycling and climbing at peak exercise, suggest that maximum VO2 may play an important role in climbing performance. Specific training methodologies should be implemented to improve aerobic power in climbers

    Temperature Assessment During Radio Frequency Ablation in Ex Vivo Long Bone by Fiber Bragg Grating Sensors

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    Thermal ablation treatments (TATs) are promising alternatives to traditional surgery for bone cancer eradication. Among several TATs, radio frequency ablation (RFA) has gained considerable ground in treating bone cancer. Therefore, tracking temperature is paramount in ensuring complete tumor destruction without injuring adjacent structures. Despite the widespread use of RFA for bone tumors, investigations on temperature distribution during this procedure are so far lacking. To date, only thermocouples and thermistors have been proposed to measure temperature during RFA in bone. However, these sensors are intended to measure temperature at a single point without information about heat propagation into the tissue during ablation. Within this context, fiber Bragg grating sensors (FBGs) can play a crucial role since their multiplexing capability enables temperature measurement at several locations. This work seeks to fill this gap by providing new insights into RFA effects on bone tissue. Experiments are performed on ex vivo porcine femurs. During trials, two commercial stainless-steel needles equipped with an optical fiber housing six FBGs each were employed to record temperature over time. This solution allowed for monitoring temperature in 12 tissue points inside the bone at a fixed distance from the RF probe, thus gaining information about the thermal distribution in a large tissue area over time. This study paves the way for a more in-depth understanding of the efficacy of RFA in bone tissue, thus providing a powerful method for temperature monitoring, potentially enhancing the treatment outcomes.</p

    "Malignant" mitral stenosis

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    Symptomatic mitral stenosis caused by a left atrial mass as the first sign of metastasis of a malignant tumor is extremely rare and frequently associated with poor prognosis. We report a case of a 59-year-old man with a history of grade 3 malignant fibrous histiocytoma on his left tigh treated by limb-sparing surgery 17 months earlier, who was admitted with 10-days of worsening dyspnea. Imaging revealed a left atrial mass protruding through the mitral valve that resulted in severe mitral stenosis. Biopsy confirmed metastasis of malignant fibrous histiocytoma
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