387 research outputs found

    ATR-FTIR spectroscopy detects alterations induced by organotin(IV) carboxylates in MCF-7 cells at sub-cytotoxic/-genotoxic concentrations.

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    The environmental impact of metal complexes such as organotin(IV) compounds is of increasing concern. Genotoxic effects of organotin(IV) compounds (0.01 μg/ml, 0.1 μg/ml or 1.0 μg/ml) were measured using the alkaline single-cell gel electrophoresis (comet) assay to measure DNA single-strand breaks (SSBs) and the cytokinesis-block micronucleus (CBMN) assay to determine micronucleus formation. Biochemical-cell signatures were also ascertained using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. In the comet assay, organotin(IV) carboxylates induced significantly-elevated levels of DNA SSBs. Elevated micronucleus-forming activities were also observed. Following interrogation using ATR-FTIR spectroscopy, infrared spectra in the biomolecular range (900 cm-1 – 1800 cm-1) derived from organotin-treated MCF-7 cells exhibited clear alterations in their biochemical-cell fingerprint compared to control-cell populations following exposures as low as 0.0001 μg/ml. Mono-, di- or tri-organotin(IV) carboxylates (0.1 μg/ml, 1.0 μg/ml or 10.0 μg/ml) were markedly cytotoxic as determined by the clonogenic assay following treatment of MCF-7 cells with ≥ 1.0 μg/ml. Our results demonstrate that ATR-FTIR spectroscopy can be applied to detect molecular alterations induced by organotin(IV) compounds at sub-cytotoxic and sub-genotoxic concentrations. This biophysical approach points to a novel means of assessing risk associated with environmental contaminants

    Excessive Soil Water Effects at Various Stages of Development on the Growth and Yield of Corn

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    The response of corn to naturally fluctuating water tables at five different stages of growth was studied for 3 years. Fifty plots of 15 m x 15 m were established in 1984 on Nicollet soil in an area that is not artificially drained. In the center of each plot, an observation well was installed for water-table measurements. Water-table hydrographs were developed for each plot annually to quantify crop stress factors from excessive wetness (SEW30, a summation of days times the height of the water table above 30 cm). The results of these studies indicate that SEW30 values of as low as 40 cm-days in the early part of the growing season can significantly reduce corn yields. Corn yields decreased linearly with the increase in SEW30 values and the Stress Day Index (SDI). Lower corn yields resulted from both decreased plant population and poor crop growth due to excessive wetness

    Tuning the Photoresponse of Nano-Heterojunction: Pressure-Induced Inverse Photoconductance in Functionalized WO3 Nanocuboids

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    S.R. and S.S. contributed equally to this work. This work was mainly supported by the Natural Science Foundation of China (Grant No. 11874076), National Science Associated Funding (NSAF, Grant No. U1530402), and Science Challenging Program (Grant No. TZ2016001). D.E. thanks the financial support from Spanish MINECO under Grant No. MAT2016-75586-C4-1-P and from Generalitat Valenciana under Grant Prometeo/2018/123, EFIMAT. The X-ray diffraction measurements were performed at the BL15U1 station, Shanghai Synchrotron Radiation Facility (SSRF) in China. The HP XAS measurements were performed at 20 ID-C, APS, ANL. APS is supported by DOE-BES, under contract no. DE-AC02-06CH11357. The authors gratefully acknowledge Professor T. Irifune for providing the nanodiamonds for the HP XAS measurements, and K. Yang (SSRF), A. G. Li (SSRF), and C. J. Sun (APS) for their support in the in situ HP measurements.Inverse photoconductivity (IPC) is a unique photoresponse behavior that exists in few photoconductors in which electrical conductivity decreases with irradiation, and has great potential applications in the development of photonic devices and nonvolatile memories with low power consumption. However, it is still challenging to design and achieve IPC in most materials of interest. In this study, pressure-driven photoconductivity is investigated in n-type WO3 nanocuboids functionalized with p-type CuO nanoparticles under visible illumination and an interesting pressure-induced IPC accompanying a structural phase transition is found. Native and structural distortion induced oxygen vacancies assist the charge carrier trapping and favor the persistent positive photoconductivity beyond 6.4 GPa. The change in photoconductivity is mainly related to a phase transition and the associated changes in the bandgap, the trapping of charge carriers, the WO6 octahedral distortion, and the electron–hole pair recombination process. A unique reversible transition from positive to inverse photoconductivity is observed during compression and decompression. The origin of the IPC is intimately connected to the depletion of the conduction channels by electron trapping and the chromic property of WO3. This synergistic rationale may afford a simple and powerful method to improve the optomechanical performance of any hybrid material.Natural Science Foundation of China (Grant No. 11874076); National Science Associated Funding (NSAF, Grant No. U1530402); Science Challenging Program (Grant No. TZ2016001); Spanish MINECO MAT2016-75586-C4-1-P; Generalitat Valenciana under Grant Prometeo/2018/123, EFIMAT; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

    BACTERIOLOGY OF MASTITIS IN BUFFALOES IN TEHSIL SAMUNDRI OF DISTRICT FAISALABAD, PAKISTAN

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    Two hundred fore-milk samples collected from 200 mastitis quarters of buffaloes (clinically mastitis quarters n = 17, sub-clinically mastitis quarters n = 183) were subjected to microbiological examination. The diagnosis of sub-clinical mastitis was based on the results of Surf Field Mastitis Test (SFMT). A total of 214 isolates of 13 different microbial species were recovered. Staphylococcus aureus was the most frequently recovered bacterial species accounting for 49.53% of all the isolates, followed by Streptococcus agalactiae (23.83%), Staphylococcus hyicus (8.88%), Staphylococcus epidermidis (6.54%), Bacillus spp. (3.74%), Staphylococcus hominis (1.40%), Escherichia coli (1.40%), Staphylococcus xylosus (0.93%), Streptococcus dysgalactiae (0.93%) and Corynebacterial spp. (0.93%). Yeast and prototheca each accounted for 0.47 percent of isolates. Two (0.93%) isolates were identified as coagulase negative staphylococci species. In view of preponderance of the contagious pathogens (S. aureus, Str. agalactiae), it is recommended that mastitis control in the area of study should be based on contagious mastitis control practice

    Borylation–Reduction–Borylation for the Formation of 1,4-Azaborines

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    This project has received funding from the Leverhulme Trust (grant Number RPG-2022-032) and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 769599). M.J.I. and E.Z.-C. also thank the EPSRC Programme Grant “Boron: Beyond the Reagent” (EP/W007517/1) for support.Given the current interest in materials containing 1,4-azaborine units, the development of new routes to these structures is important. Carbonyl directed electrophilic borylation using BBr3 is a facile method for the ortho-borylation of N,N-diaryl-amide derivatives. Subsequent addition of Et3SiH results in carbonyl reduction and then formation of 1,4-azaborines that can be protected in situ using a Grignard reagent. Overall, borylation–reduction–borylation is a one-pot methodology to access 1,4-azaborines from simple precursors.Publisher PDFPeer reviewe

    N-Heterocyclic carbene acyl anion organocatalysis by ball-milling

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    The ability to conduct N‐heterocyclic carbene‐catalysed acyl anion chemistry under ball‐milling conditions is reported for the first time. This process has been exemplified through applications to intermolecular‐benzoin, intramolecular‐benzoin, intermolecular‐Stetter and intramolecular‐Stetter reactions including asymmetric examples and demonstrates that this mode of mechanistically complex organocatalytic reaction can operate under solvent‐minimised conditions

    Sustaining solidarity through social media? Employee social media groups as an emerging platform for collectivism in Pakistan

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    Forging solidarity or a collective approach amongst seemingly privileged white-collar professionals has been seen as challenging process. However, many banking employees in Pakistan feel marginalized and lack formal collective mechanisms within their workplaces to voice their concerns, leading some to participate in social-media groups. Drawing on various discussions linked to labour process perspectives, we examine how these banking employees use social media as a means to create broader and diverse collective bonds within their profession and build bridges to similar employees in other organizations within the sector. By doing so, we reveal that employees post on social media to express and affirm their concerns, offer broader support with one another, ‘cope’ with existing circumstances, highlight their unrewarded professionalism, and share relevant information around collective issues and experiences. Employees do not solely use social media to voice their immediate criticisms about their work. The paper draws on and contributes to new debates on collectivism and solidarity, revealing the opportunities for actions on social media

    Tailoring surface properties, biocompatibility and corrosion behavior of stainless steel by laser induced periodic surface treatment towards developing biomimetic stents

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    Laser-Induced Periodic Surface Structures (LIPSS) holds great potential for regenerative biomedicine. Creating highly precise LIPSS enables to generate biomimetic implant surfaces with improved properties. The present study focuses on the fabrication and investigation of laser-treated stainless steel samples with applied linear LIPSS patterns with grooves made by means of a picosecond laser system using wavelengths of 1064 nm and 532 nm. To investigate properties of the laser-treated surfaces and to understand the basics of cell-surface interactions between the LIPSS and human Umbilical Cord Mesenchymal Stem Cells (UCMSC), flat stainless steel samples with various applied nanopatterns were used. Such LIPSSs demonstrated higher surface roughness, good biocompatibility, lower wettability and higher corrosion resistance compared to the untreated (polished) spec-imens. The surface roughness of laser-treated samples was in microscale that enabled adhesion and migration of endothelial cells, thus increasing the likelihood for endothelialisation. This thereby could reduce the chances for the development of Late Stent Thrombosis (LST) and In-Stent Restenosis (ISR). Furthermore, laser textured surfaces demonstrated an environment supportive for cell attachment, proliferation and alignment with the nanogroves. Therefore, application of the biomimetic nanopatterns could help to overcome frequent post-surgery complications after the stent implantation
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