Exploration of Cd(II)/pseudohalide/di-2-pyridyl ketone chemistry - rational synthesis, structural analysis and photoluminescence

A systematic investigation of CdIJII)–(py)2CO–X systems (X = N3 −, NCO− and NCS−) was conducted, and the following cadmium(II) coordination compounds [Cd(SCN)2{(py)2C(OCH3)(OH)}]n (1), [Cd2(SCN)4{(py)2- C(OCH3)(OH)}2] (2), [Cd4(SCN)4{(py)2C(OCH3)(O)}4] (3), [Cd4(N3)4{(py)2C(OCH3)(O)}4] (4), [Cd4(N3)4{(py)2- C(OH)(O)}2{(py)2C(OCH3)(O)}2] (5), [Cd4(NCO)4{(py)2C(OCH3)(O)}4] (6), [Cd4(NCO)4{(py)2C(OH)(O)}2{(py)2- C(OCH3)(O)}2] (7), [Cd4(N3)2(NO3)2{(py)2C(OH)(O)}2{(py)2C(OCH3)(O)}2] (8) and [Cd4(NCO)2(NO3)2{(py)2C(OH)(O)}2{(py)2C(OCH3)(O)}2] (9a and 9b) were successfully synthesized and characterized by single-crystal diffraction, X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) analysis and IR spectroscopy. The fluorescence properties of 1–9 were studied in the solid state and compared to the fluorescence of di-2-pyridyl ketone. The photoluminescence behaviour of 2–9 was also investigated in acetonitrile solution. The X-ray studies demonstrated a cooperative impact of the organic ligand and auxiliary inorganic ion on the final molecular architectures of the cadmium(II) coordination compounds. Also, the essential roles of intermolecular interactions (hydrogen bonds, π–π stacking interactions and weak O⋯S contacts) in the creation of molecular architectures were discussed

Critical Song Features for Auditory Pattern Recognition in Crickets

Many different invertebrate and vertebrate species use acoustic communication for pair formation. In the cricket Gryllus bimaculatus, females recognize their species-specific calling song and localize singing males by positive phonotaxis. The song pattern of males has a clear structure consisting of brief and regular pulses that are grouped into repetitive chirps. Information is thus present on a short and a long time scale. Here, we ask which structural features of the song critically determine the phonotactic performance. To this end we employed artificial neural networks to analyze a large body of behavioral data that measured females’ phonotactic behavior under systematic variation of artificially generated song patterns. In a first step we used four non-redundant descriptive temporal features to predict the female response. The model prediction showed a high correlation with the experimental results. We used this behavioral model to explore the integration of the two different time scales. Our result suggested that only an attractive pulse structure in combination with an attractive chirp structure reliably induced phonotactic behavior to signals. In a further step we investigated all feature sets, each one consisting of a different combination of eight proposed temporal features. We identified feature sets of size two, three, and four that achieve highest prediction power by using the pulse period from the short time scale plus additional information from the long time scale

Adaptation Reduces Variability of the Neuronal Population Code

Sequences of events in noise-driven excitable systems with slow variables often show serial correlations among their intervals of events. Here, we employ a master equation for general non-renewal processes to calculate the interval and count statistics of superimposed processes governed by a slow adaptation variable. For an ensemble of spike-frequency adapting neurons this results in the regularization of the population activity and an enhanced post-synaptic signal decoding. We confirm our theoretical results in a population of cortical neurons.Comment: 4 pages, 2 figure

Histological, histochemical and fine structure studies of the lacrimal gland and superficial gland of the third eyelid and their significance on the proper function of the eyeball in alpaca (Vicugna pacos)

The lacrimal gland (LG) and superficial gland of the third eyelid (SGTE) belong to accessory organs of the eye. The aim of the present studies was to evaluate the histological, histochemical and fine structure of the LG and SGTE obtained from 3 adult females and 2 adult males of alpaca (Vicugna pacos). The LG was situated in the dorsolateral angle of the orbit between the dorsal rectus and the lateral rectus muscles. The SGTE was located between the medial rectus muscle, the ventral rectus muscle and was partially covered by the ventral oblique muscle of the eyeball. There were no effect of gender on the morphometry of examined LG and SGTE. The third eyelid resembles an anchor in shape. During histological and ultrastructural analyses using light and transmission electron microscopy, it was established that the LG and SGTE are tubulo-acinar glands with mucoserous characters. The LG contains either lymphocytes or plasma cells, while SGTE had rare plasma cells and numerous lymphocytes in connective tissue. The cartilage of the third eyelid was composed of hyaline tissue. Numerous aggregations of lymphocytes as lymph nodules in bulbar surface of the third eyelid were observed. The LG and SGTE secretory cells exhibited a similar ultrastructure appearance in electron microscopic examination, with secretory cells tightly filled with intracytoplasmatic secretory granules and numerous clusters of mucus of different sizes which were observed in the peripheral cells compartment

Cytotoxic activity of proteins isolated from extracts of Corydalis cava tubers in human cervical carcinoma HeLa cells

<p>Abstract</p> <p>Background</p> <p><it>Corydalis cava </it>Schweigg. & Koerte, the plant of numerous pharmacological activities, together with the studied earlier by our group <it>Chelidonium majus </it>L. (Greater Celandine), belong to the family <it>Papaveraceae</it>. The plant grows in Central and South Europe and produces the sizeable subterraneous tubers, empty inside, which are extremely resistant to various pathogen attacks. The <it>Corydalis sp. </it>tubers are a rich source of many biologically active substances, with the extensive use in European and Asian folk medicine. They have analgetic, sedating, narcotic, anti-inflammatory, anti-allergic and anti-tumour activities. On the other hand, there is no information about possible biological activities of proteins contained in <it>Corydalis cava </it>tubers.</p> <p>Methods</p> <p>Nucleolytic proteins were isolated from the tubers of <it>C. cava </it>by separation on a heparin column and tested for DNase activity. Protein fractions showing nucleolytic activity were tested for cytotoxic activity in human cervical carcinoma HeLa cells. Cultures of HeLa cells were conducted in the presence of three protein concentrations: 42, 83 and 167 ng/ml during 48 h. Viability of cell cultures was appraised using XTT colorimetric test. Protein fractions were separated and protein bands were excised and sent for identification by mass spectrometry (LC-ESI-MS/MS).</p> <p>Results</p> <p>The studied protein fractions showed an inhibiting effect on mitochondrial activity of HeLa cells, depending on the administered dose of proteins. The most pronounced effect was obtained with the highest concentration of the protein (167 ng/ml) - 43.45 ± 3% mitochondrial activity of HeLa cells were inhibited. Mass spectrometry results for the proteins of applied fractions showed that they contained plant defense- and pathogenesis-related (PR) proteins.</p> <p>Conclusions</p> <p>The cytotoxic effect of studied proteins toward HeLa cell line cells has been evident and dependent on increasing dose of the protein. The present study, most probably, represents the first investigations on the effect of purified PR proteins from tuber extracts of a pharmacologically active plant on cell lines.</p

Ecological regime shift preserved in the Anthropocene stratigraphic record

Palaeoecological data are unique historical archives that extend back far beyond the last several decades of ecological observations. However, the fossil record of continental shelves has been perceived as too coarse (with centennial-millennial resolution) and incomplete to detect processes occurring at yearly or decadal scales relevant to ecology and conservation. Here, we show that the youngest (Anthropocene) fossil record on the northern Adriatic continental shelf provides decadal-scale resolution that accurately documents an abrupt ecological change affecting benthic communities during the twentieth century. The magnitude and the duration of the twentieth century shift in body size of the bivalve Corbula gibba is unprecedented given that regional populations of this species were dominated by small-size classes throughout the Holocene. The shift coincided with compositional changes in benthic assemblages, driven by an increase from approximately 25% to approximately 70% in median per-assemblage abundance of C. gibba. This regime shift increase occurred preferentially at sites that experienced at least one hypoxic event per decade in the twentieth century. Larger size and higher abundance of C. gibba probably reflect ecological release as it coincides with an increase in the frequency of seasonal hypoxia that triggered mass mortality of competitors and predators. Higher frequency of hypoxic events is coupled with a decline in the depth of intense sediment mixing by burrowing benthic organisms from several decimetres to less than 20 cm, significantly improving the stratigraphic resolution of the Anthropocene fossil record and making it possible to detect sub-centennial ecological changes on continental shelves

Variation in metapopulation dynamics of a wetland mammal: The effect of hydrology.

Key factors affecting metapopulation dynamics of animals include patch size, isolation, and patch quality. For wetland-associated species, hydrology can affect patch availability, connectivity, and potentially habitat quality; and therefore drive metapopulation dynamics. Wetlands occurring on natural river floodplains typically have more dynamic hydrology than anthropogenic wetlands. Our overall objective was to assess the multiyear spatial and temporal variation in occupancy and turnover rates of a semi-aquatic small mammal at two hydrologically distinct wetland complexes. We live-trapped marsh rice rats (Oryzomys palustris) for 3 yr and \u3e50 000 trap nights at nine wetland patches on the Mississippi River floodplain and 14 patches at a reclaimed surface mine in southern Illinois. We used dynamic occupancy modeling to estimate initial occupancy, detection, colonization, and extinction rates at each complex. Catch per unit effort (rice rats captured/1000 trap nights) was markedly higher at the floodplain site (28.1) than the mining site (8.1). We found no evidence that temperature, rainfall, or trapping effort affected detection probability. Probability of initial occupancy was similar between sites and positively related to patch size. Patch colonization probability at both sites was related negatively to total rainfall 3 weeks prior to trapping, and varied across years differently at each site. We found interacting effects of site and rainfall on extinction probability: extinction increased with total rainfall 3 months prior to trapping but markedly more at the floodplain site than at the mining site. These site-specific patterns of colonization and extinction are consistent with the rice rat metapopulation in the floodplain exhibiting a habitat-tracking dynamic (occupancy dynamics driven by fluctuating quality), whereas the mineland complex behaved more as a classic metapopulation (stochastic colonization & extinction). Our study supports previous work demonstrating metapopulation dynamics in wetland systems being driven by changes in patch quality (via hydrology) rather than solely area and isolation