869 research outputs found
The temperature dependence of the development of the embryo in Mesocyclops leuckarti (Claus) and Cyclops scutifer
This work is mainly intended as an addition to the studies of the populations dynamics of Cyclops scutifer, which is part of the ”Latn ja jaure project” (a study of the principles involved in the ecosystem of a small -initially fish free- mountain lake, before and after the introduction of fish). The field work consisted of sampling in Lake Erken in Roslagen in June, July and September, as well as in Latn ja jaure in the Abisko mountains in August and September of 1965. Additional sampling was done in Latn ja jaure for the study of the horizontal, vertical and temporal distribution of Cyclops scutifer, as well as the in situ development of the different stages. These samples have been analysed in such a way as to fit into the frame work of future studies on the population dynamics of Cyclops scutifer, The main aim of the present investigation is the determination of the dependence upon tempera- tare of the development of the embryo in the subarctic Cyclops scutifer as compared with the conditions found in the warm water species Mesocyclops leuckarti
Molecular mechanism regulating myosin and cardiac functions by ELC
The essential myosin light chain (ELC) is involved in modulation of force generation of myosin motors and cardiac contraction, while its mechanism of action remains elusive. We hypothesized that ELC could modulate myosin stiffness which subsequently determines its force production and cardiac contraction. We therefore generated heterologous transgenic mouse (TgM) strains with cardiomyocyte-specific expression of ELC with human ventricular ELC (hVLC-1; TgM(hVLC-1)) or E56G-mutated hVLC-1 (hVLC-1(E56G); TgM(E56G)). hVLC-1 or hVLC-1(E56G) expression in TgM was around 39% and 41%, respectively of total VLC-1. Laser trap and in vitro motility assays showed that stiffness and actin sliding velocity of myosin with hVLC-1 prepared from TgM(hVLC-1) (1.67pN/nm and 2.3{my}m/s, respectively) were significantly higher than myosin with hVLC-1(E56G) prepared from TgM(E56G) (1.25pN/nm and 1.7{my}m/s, respectively) or myosin with mouse VLC-1 (mVLC-1) prepared from C57/BL6 (1.41 pN/nm and 1.5+-0.03 {my}m/s, respectively). Maximal left ventricular pressure development of isolated perfused hearts in vitro prepared from TgM(hVLC-1) (80.0mmHg) were significantly higher than hearts from TgM(E56G) (66.2mmHg) or C57/BL6 (59.3+-3.9 mmHg). These findings show that ELCs decreased myosin stiffness, in vitro motility, and thereby cardiac functions in the order hVLC-1 > hVLC-1(E56G) ≈ mVLC-1. They also suggest a molecular pathomechanism of cardiomyopathies caused by hVLC-1 mutations
Hydrogen sorption in the LiH-LiF-MgB2 system
A composite material in the LiH-LiF-MgB2 system has been synthesized by high-energy ball milling. Some peaks in addition to that of the binary 2LiH-MgB2 and 2LiF-MgB2 systems are observed for the composite material by high-pressure differential scanning calorimetry (HP-DSC), indicating the formation of intermediate phases. In situ synchrotron radiation powder X-ray diffraction (SR-PXD) performed at 60 bar of H-2 and 390 degrees C shows a superposition of both reaction pathways that are typical for 2LiH-MgB2 and 2LiF-MgB2. After hydrogen absorption of the LiH-LiF-MgB2 composite the vibrational modes of LiBH4 were observed by attenuated total reflection infrared (ATR-IR) spectroscopy. The F-19 MAS NMR spectrum of the LiF-LiBH4 sample after heat treatment in hydrogen is strongly dominated by the centerband and spinning sidebands from LiF; in addition, a low-intensity resonance, very similar to that of [BF4](-) ion, is identified
Possibilità di differenziazione degli elettrodi cocleari nelle misurazioni radiologiche della posizione intracocleare e dell'angolo cordo-facciale
Con l'incremento del numero di impianti cocleari effettuati, il controllo di qualità è divenuto sempre più importante. Oltre alle misurazioni biofisiche intraoperatorie ci si può avvalere dell'imaging radiologico. Una nuova tecnica utilizzata in questo campo è il Cone Beam CT (CBCT). Nel presente studio sono stati valutati 65 casi (35 Nucleus Contour AdvanceCochlear; 30 Flex SoftMedEl) studiati mediante CBCT (Accu-I-tomo F17, Morita, Kyoto, Japan). Nello specifico sono stati rilevati: l'angolo di inserzione, l'altezza dell'impianto, la distanza dell'elettrodo dalla parete mediale o laterale, l'angolo tra la corda del timpano e il nervo facciale e la posizione precisa del filo dell'elettrodo nell'angolo cordo-facciale. È stato inoltre possibile valutare la differenza tra il decorso peri-modiolare e laterale degli elettrodi. I dati presentati dimostrano l'accuratezza e il vantaggio della CBCT nella visualizzazione di piccole strutture grazie al ridotto numero di artefatti da indurimento del fascio. Inoltre nel 75% dei pazienti è stato possibile visualizzare l'angolo tra la corda del timpano e il nervo facciale. È stato possibile notare differenze significative fra i vari tipi di elettrodo in funzione del tipo di rapporto con il nervo facciale. In conclusione mediante la CBCT è possibile ottenere una visualizzazione precisa e dettagliate misurazioni della posizione intracocleare dei diversi elettrodi. È persino possibile la corretta valutazione della posizione dell'elettrodo rispetto all'angolo cordo- facciale. La CBCT è quindi, dal nostro punto di vista, un utile strumento per il controllo intra e post-operatorio degli impianti cocleari
Reanalysis of the NCCN PD-L1 Companion Diagnostic Assay Study for Lung Cancer in the Context of PD-L1 Expression Findings in Triple-Negative Breast Cancer
The companion diagnostic test for checkpoint inhibitor immune therapy is an immunohistochemical test for PD-L1. The test has been shown to be reproducible for expression in tumor cells, but not in immune cells. Immune cells were used in the IMpassion130 trial which showed PD-L1 expression was associated with a better outcome. Two large studies have been done assessing immune cell PD-L1 expression in lung cancer. Here, we reanalyze one of those studies, to show that, even with an easier scoring method, there is still only poor agreement between assays and pathologist for immune cell PD-L1 expression
Magnetic state of plutonium ion in metallic Pu and its compounds
By LDA+U method with spin-orbit coupling (LDA+U+SO) the magnetic state and
electronic structure have been investigated for plutonium in \delta and \alpha
phases and for Pu compounds: PuN, PuCoGa5, PuRh2, PuSi2, PuTe, and PuSb. For
metallic plutonium in both phases in agreement with experiment a nonmagnetic
ground state was found with Pu ions in f^6 configuration with zero values of
spin, orbital, and total moments. This result is determined by a strong
spin-orbit coupling in 5f shell that gives in LDA calculation a pronounced
splitting of 5f states on f^{5/2} and f^{7/2} subbands. A Fermi level is in a
pseudogap between them, so that f^{5/2} subshell is already nearly completely
filled with six electrons before Coulomb correlation effects were taken into
account. The competition between spin-orbit coupling and exchange (Hund)
interaction (favoring magnetic ground state) in 5f shell is so delicately
balanced, that a small increase (less than 15%) of exchange interaction
parameter value from J_H=0.48eV obtained in constrain LDA calculation would
result in a magnetic ground state with nonzero spin and orbital moment values.
For Pu compounds investigated in the present work, predominantly f^6
configuration with nonzero magnetic moments was found in PuCoGa5, PuSi2, and
PuTe, while PuN, PuRh2, and PuSb have f^5 configuration with sizeable magnetic
moment values. Whereas pure jj coupling scheme was found to be valid for
metallic plutonium, intermediate coupling scheme is needed to describe 5f shell
in Pu compounds. The results of our calculations show that both spin-orbit
coupling and exchange interaction terms in the Hamiltonian must be treated in a
general matrix form for Pu and its compounds.Comment: 20 pages, LaTeX; changed discussion on reference pape
Discovery of Prognostic Markers for Early-Stage High-Grade Serous Ovarian Cancer by Maldi-Imaging
With regard to relapse and survival, early-stage high-grade serous ovarian (HGSOC) patients comprise a heterogeneous group and there is no clear consensus on first-line treatment. Currently, no prognostic markers are available for risk assessment by standard targeted immunohistochemistry and novel approaches are urgently required. Here, we applied MALDI-imaging mass spectrometry (MALDI-IMS), a new method to identify distinct mass profiles including protein signatures on paraffin-embedded tissue sections. In search of prognostic biomarker candidates, we compared proteomic profiles of primary tumor sections from early-stage HGSOC patients with either recurrent (RD) or non-recurrent disease (N = 4; each group) as a proof of concept study. In total, MALDI-IMS analysis resulted in 7537 spectra from the malignant tumor areas. Using receiver operating characteristic (ROC) analysis, 151 peptides were able to discriminate between patients with RD and non-RD (AUC > 0.6 or 0.7). These results confirm that in using IMS, we could identify new candidates to predict clinical outcome and treatment extent for patients with early-stage HGSOC
Comparative Analysis of Drug Interactions with Antibacterial Agents in the Treatment of Community-Acquired Pneumonia
According to the World Health Organisation, pneumonia and other lower respiratory tract infections are one of the leading causes of death all over the world. Simultaneous treatment of pneumonia with antibacterial drugs and concomitant medicines may result in adverse drug reactions (ADRs). The aim of the study was to analyse ADRs resulting from drug-drug interactions in different empiric antibiotic treatment regimens used for mild community-acquired pneumonia (CAP), taking into account the concomitant symptomatic non-antibacterial treatment and chronic disease treatment. Materials and methods: the authors analysed spontaneous reports in the VigiBase global database (starting from the date the database was created and until 15 February 2021) on ADRs resulting from interactions of medicinal products included in the Russian clinical guidelines for CAP.Results: the authors compiled a list of antibacterial drugs (amoxicillin+clavulanic acid, amoxicillin, ampicillin, azithromycin, clarithromycin, levofloxacin, moxifloxacin, cefotaxime, ceftriaxone, linezolid), as well as lists of medicinal products for symptomatic and concomitant treatment, based on the approved guidelines for management of CAP and frequent comorbid chronic diseases. They searched VigiBase for ADRs that may have resulted from drug-drug interactions involving these medicinal products. Conclusions: the analysis of adverse reactions used for mild CAP treatment demonstrated that the largest number of ADRs were associated with drug-drug interactions involving azithromycin, while the smallest number of ADRs were associated with cefotaxime and ceftriaxone. Further study of drug-drug interactions will help to prevent potential ADRs, identify rational drug combinations, and improve the existing patient management strategies
Using Strategic Movement to Calibrate a Neural Compass: A Spiking Network for Tracking Head Direction in Rats and Robots
The head direction (HD) system in mammals contains neurons that fire to represent the direction the animal is facing in its environment. The ability of these cells to reliably track head direction even after the removal of external sensory cues implies that the HD system is calibrated to function effectively using just internal (proprioceptive and vestibular) inputs. Rat pups and other infant mammals display stereotypical warm-up movements prior to locomotion in novel environments, and similar warm-up movements are seen in adult mammals with certain brain lesion-induced motor impairments. In this study we propose that synaptic learning mechanisms, in conjunction with appropriate movement strategies based on warm-up movements, can calibrate the HD system so that it functions effectively even in darkness. To examine the link between physical embodiment and neural control, and to determine that the system is robust to real-world phenomena, we implemented the synaptic mechanisms in a spiking neural network and tested it on a mobile robot platform. Results show that the combination of the synaptic learning mechanisms and warm-up movements are able to reliably calibrate the HD system so that it accurately tracks real-world head direction, and that calibration breaks down in systematic ways if certain movements are omitted. This work confirms that targeted, embodied behaviour can be used to calibrate neural systems, demonstrates that ‘grounding’ of modelled biological processes in the real world can reveal underlying functional principles (supporting the importance of robotics to biology), and proposes a functional role for stereotypical behaviours seen in infant mammals and those animals with certain motor deficits. We conjecture that these calibration principles may extend to the calibration of other neural systems involved in motion tracking and the representation of space, such as grid cells in entorhinal cortex
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