Rapid, learning-induced inhibitory synaptogenesis in murine barrel field

The structure of neurons changes during development and in response to injury or alteration in sensory experience. Changes occur in the number, shape, and dimensions of dendritic spines together with their synapses. However, precise data on these changes in response to learning are sparse. Here, we show using quantitative transmission electron microscopy that a simple form of learning involving mystacial vibrissae results in approximately 70% increase in the density of inhibitory synapses on spines of neurons located in layer IV barrels that represent the stimulated vibrissae. The spines contain one asymmetrical (excitatory) and one symmetrical (inhibitory) synapse (double-synapse spines), and their density increases threefold as a result of learning with no apparent change in the density of asymmetrical synapses. This effect seems to be specific for learning because pseudoconditioning (in which the conditioned and unconditioned stimuli are delivered at random) does not lead to the enhancement of symmetrical synapses but instead results in an upregulation of asymmetrical synapses on spines. Symmetrical synapses of cells located in barrels receiving the conditioned stimulus also show a greater concentration of GABA in their presynaptic terminals. These results indicate that the immediate effect of classical conditioning in the "conditioned" barrels is rapid, pronounced, and inhibitory

Rola badań budowy technicznej i rozpoznania warsztatu artysty na przykładzie twórczości Meli Muter

The research of the technical structure of art works aim towards answering basic questions: what materials are used, what is their quality, in what quantity and how they are used. On how many original (technological) layers does the structure of work of art, how thick and of what composition are they. Apart from materials used in the process of art creation, materials added during conservation or reparation, so called secondary elements, are also a subject to research. It is important to determine what influence they have on the final perception of the work, and to what extent they may falsify or tamper with it. The information on the painting’s structure does not always directly influence the interpretation of its humanistic character, however it does have a crucial meaning in explaining what means were used in order to obtain a concrete artistic expression of the work of art. Moreover, it allows to understand how the individual elements, sometimes of little importance as it may seem, co-create its complicated nature and by what technological process accompanies it.The research of the technical structure of art works aim towards answering basic questions: what materials are used, what is their quality, in what quantity and how they are used. On how many original (technological) layers does the structure of work of art, how thick and of what composition are they. Apart from materials used in the process of art creation, materials added during conservation or reparation, so called secondary elements, are also a subject to research. It is important to determine what influence they have on the final perception of the work, and to what extent they may falsify or tamper with it. The information on the painting’s structure does not always directly influence the interpretation of its humanistic character, however it does have a crucial meaning in explaining what means were used in order to obtain a concrete artistic expression of the work of art. Moreover, it allows to understand how the individual elements, sometimes of little importance as it may seem, co-create its complicated nature and by what technological process accompanies it

Nieinwazyjne badania in situ wybranych obrazów z kolekcji malarstwa i pasteli autorstwa Meli Muter za pomocą tomografii optycznej OCT

Optical Coherence Tomography is a non-contact and non-invasive technique of depth-resolved structural imaging within media scattering and/or absorbing nearinfrared light moderately. It utilizes a concept of low-coherence interferometry and thus light sources must be characterized by low temporal (to ensure high axial resolution) and high spatial (to ensure high sensitivity) coherence. The instrument used in this study has 4 μm axial resolution and over 100 dB sensitivity. The modular construction based on fiber optics makes it fairly easy transportable and not requiring optical table mounting. The system’s portability together with fast and straightforward data acquisition, makes OCT especially well suited for quick  in situ evaluation of large museum collections of paintings. A vast collection of seventy-one oil paintings and over one hundred drawings, watercolours, and graphics by Mela Muter (Maria Melania Mutermilch, 1876, Warsaw – 1967, Paris), gathered by Bolesław and Lina Nawrocki, is now on deposit to the Nicolaus Copernicus University Museum in Toruń. Artistically active in the first half of the twentieth century within the École de Paris, Mela Muter became recognized mostly for the portraits depicting socialites of the time, as well as images of motherhood, children and old people. The collection brings specific conservation problems. Since the works were mostly acquired from Muter herself, the attribution is not in question. Nevertheless, the majority of paintings bear signs of extent conservation treatment and/ or alterations performed by the artist in her late years, possibly including adding signatures. The aim of the survey of the group of nine Mela Muter’s paintings and two pastels was to define the conservation issues as well as to indicate the objects and areas for further examination with various analytical techniques. In result, the evaluation of secondary layers (varnishes and putties) was performed for seven paintings. The structure of the paint layer in the area of the signature was analyzed in three paintings. Finally, in case of two pastel paintings, the safety of pigment layer (its distance to the glass) was assessed.

Pause behaviour within reformulations and the proficiency level of second language learners of English

This research reports on a quantitative analysis of the combination of two types of disfluency, reformulations and pauses, in the speech of lower intermediate and advanced speakers of English as a second language (L2). The present study distinguishes between corrections and false starts within the category of reformulations as well as between silent and filled pauses. It focuses on the extent to which pause behavior within reformulations varies according to the stage of L2 development and the type of reformulation used. An analysis was made of 56 L2 speakers’ 2-min monologues. The results showed that lower intermediate and advanced speakers differed on the frequency of silent pauses inserted in corrections but not on their frequency in false starts. This suggests that false starts depend less on proficiency level, and may reflect temporary problems with conceptual encoding or extralinguistic factors that contribute to the efficacy of L2 production rather than difficulties with linguistic processing per se. The frequency of silent pauses rather than silent pause duration or the frequency and duration of filled pauses appeared to be the only marker to differentiate between false starts and corrections across the two proficiency groups

Computational modeling of ovarian cancer dynamics suggests optimal strategies for therapy and screening

High-grade serous tubo-ovarian carcinoma (HGSC) is a major cause of cancer-related death. Treatment is not uniform, with some patients undergoing primary debulking surgery followed by chemotherapy (PDS) and others being treated directly with chemotherapy and only having surgery after three to four cycles (NACT). Which strategy is optimal remains controversial. We developed a mathematical framework that simulates hierarchical or stochastic models of tumor initiation and reproduces the clinical course of HGSC. After estimating parameter values, we infer that most patients harbor chemoresistant HGSC cells at diagnosis and that, if the tumor burden is not too large and complete debulking can be achieved, PDS is superior to NACT due to better depletion of resistant cells. We further predict that earlier diagnosis of primary HGSC, followed by complete debulking, could improve survival, but its benefit in relapsed patients is likely to be limited. These predictions are supported by primary clinical data from multiple cohorts. Our results have clear implications for these key issues in HGSC management

Stopping power of Au for silver ions at low velocities

Energy loss measurements for the slowing down of Ag ions in Au, in the velocity range 1:6v0 < v < 4:4v0, where v0 is the Bohr velocity, are presented. The measurements were performed using the Doppler shift technique and also with a new method, where a secondary beam of low velocity heavy ions is produced by elastic scattering of the accelerated beam. The results are compared to the SRIM2000 calculations (www.srim.org) and to recent measurements in this velocity region

A nanostructural view of the cell wall disassembly process during fruit ripening and postharvest storage by atomic force microscopy

Background: The mechanical properties of parenchyma cell walls and the strength and extension of adhesion areas between adjacent cells, jointly with cell turgor, are main determinants of firmness of fleshy fruits. These traits are modified during ripening leading to fruit softening. Cell wall modifications involve the depolymerisation of matrix glycans and pectins, the solubilisation of pectins and the loss of neutral sugars from pectin side chains. These changes weaken the cell walls and increase cell separation, which in combination with a reduction in cell turgor, bring about textural changes. Atomic force microscopy (AFM) has been used to characterize the nanostructure of cell wall polysaccharides during the ripening and postharvest storage of several fruits. This technique allows the imaging of individual polymers at high magnification with minimal sample preparation. Scope and approach: This paper reviews the main features of the cell wall disassembly process associated to fruit softening from a nanostructural point of view, as has been provided by AFM studies. Key findings and conclusions: AFM studies show that pectin size, ramification and complexity is reduced during fruit ripening and storage, and in most cases these changes correlate with softening. Postharvest treatments that improve fruit quality have been proven to preserve pectin structure, suggesting a clear link between softening and pectin metabolism. Nanostructural characterization of cellulose and hemicellulose during ripening has been poorly explored by AFM and the scarce results available are not conclusive. Globally, AFM could be a powerful tool to gain insights about the bases of textural fruit quality in fresh and stored fruits