Water-potential control by colloidal gels

Summary The adsorption of water by colloids might be applied to control water potentials in pedological research and in physiological studies of plants, animals and micro-organisms. Aqueous gels of gelatine were successfully calibrated in terms of water potentials over the range relevant to such studies.     

Eutrophication of the Dutch Wadden Sea: External nutrient loadings of the Marsdiep and Vliestroom basin

The increasing P and N content in the two main tidal basins in the western Dutch Wadden Sea, the Marsdiep and the Vliestroom basin, has been reconstructed from the 50s onwards. The area is enriched with nutrients by two sources both originating from the river Rhine, one being the discharge from Lake IJssel and the other the exchange with the coastal zone of the North Sea. Due to a buffering by Lake IJssel for about 15–20 years, the eutrophication of the western Wadden Sea showed a time lag compared with the continuously increasing nutrient concentrations in the river Rhine and the coastal zone of the North Sea. At present, the primary production in part of the area still seems to be nutrient limited in summer, while loadings have already been decreasing in recent years. So far, no severe, negative effects on the ecosystem have been reported. Some remarks are made on the eutrophication in other parts of the Dutch' Wadden Sea in relation to the hydrographic characteristics of these areas. Presented at the VI International Wadden Sea Symposium (Biologische Anstalt Helgoland, Wattenmeerstation Sylt, D-2282 List, FRG, 1–4 November 1988) Publication No. 18 of the project “Ecological Research of the North Sea and Wadden Sea” (EON)     

In Vitro Evaluation of Antagonism of Endophytic Colletotrichum gloeosporioides Against Potent Fungal Pathogens of Camellia sinensis

An endophytic fungus isolated from Camellia sinensis, Assam, Northeastern India was identified as Colletotrichum gloeosporioides on the basis of morphological characteristics and rDNA ITS analysis. This endophytic fungus was evaluated for growth inhibition against tea pathogens Pestalotiopsis theae and Colletotrichum camelliae. One isolate of C. gloeosporioides showed strong antagonistic activity against Pestalotiopsis theae (64 %) and moderate activity against C. camelliae (37 %). Fifty percent cell-free culture filtrate from 5-day-old cultures showed highest antagonistic activity against both the pathogens although the inhibition percent was less as compared to dual culture. In the experiment of volatile compounds none of the isolates of C. gloeosporioides strains showed visible inhibition against P. theae and C. camelliae. The activity of extracellular hydrolytic enzymes chitinase and protease was also high in this culture fluid and measured 10 and 4.3 IU/μl, respectively.     

Insight into Prolonged Cycling Life of 4 V All-Solid-State Polymer Batteries by a High-Voltage Stable Binder

Polyethylene oxide (PEO) based solid polymer electrolytes (SPEs) are incompatible with the 4 V class cathodes such as LiCoO₂ due to the limited electrochemical oxidation window of PEO. Herein, a number of binders including commonly used binders PEO, polyvinylidene fluoride (PVDF), and carboxyl-rich polymer (CRP) binders such as sodium alginate (Na-alginate) and sodium carboxymethyl cellulose, are studied for application in the 4 V class all-solid-state polymer batteries (ASSPBs). The results show ASSPBs with CRP binders exhibit superior cycling performance up to 1000 cycles (60% capacity retention, almost 10 times higher than those with PEO and PVDF binders). Synchrotron-based X-ray absorption spectroscopy (XAS), morphology studies and density functional theory studies indicate that, with their carboxyl groups, CRPs can strongly bind the electrode materials together, and work as coating materials to protect the cathode/SPE interface. Cyclic voltammetry studies indicate that CRP binders are more stable at high voltage compared to PEO and PVDF. The stability under high voltage and the coating property of CRP binders contribute to stable cathode/SPE interfaces as disclosed by the X-ray photoelectron spectroscopy and Co L-edge XAS results, enabling long cycling life, high performance 4 V class ASSPBs.     

Reaction products from platinum(IV) amine compounds and 5'-GMP are mainly bis(5'-GMP)platinum(II) amine adducts

The reaction products obtained from mixtures of 5'-GMP and platinum(IV) compounds with formula Pt(IV)Cl4(LL) and Pt(IV)Cl2(OH)2(LL) (LL representing two monodentate or one bidentate amine ligand) have been characterized by proton NMR spectroscopy. The amines used are NH3, H2N-CH2-CH2-NH2 (ethylenediamine, en), H2N-CH2-C(CH3)2-CH2-NH2 (2,2-dimethyl-1,3-diaminopropane, dmdap), and HC(CH3)2-NH2 (isopropylamine, ipa). Conditions varied during the reaction are pH (values of 4, 7, and 10), effect of visible light, and addition of vitamin C as a reducing agent. In all cases, the major product appeared to be the bis(5'-GMP)(LL)Pt(II) compound. The pH effect is limited; i.e., at pH 4 the reactions proceed somewhat faster than at neutral pH, while at pH 10 slower reactions occur. The illumination with visible light also induces only slight differences in the yields of the products. On the other hand, when vitamin C is present, the reactions proceed quite rapidly, resulting in the same main product but in higher yields (up to 80%). The facts that apparently no Pt(IV) adducts with 5'-GMP can be observed under these conditions and that the major products are bis(5'-GMP)(LL)Pt(II) compounds clearly support the hypothesis that the antitumor activity of certain platinum(IV) compounds is based upon in vivo reduction to the corresponding platinum(II) compounds.     

N-ras mutations in human cutaneous melanoma from sun-exposed body sites.

In 7 of 37 patients with cutaneous melanoma, mutations in the N-ras gene were found. The primary tumors of these seven patients were exclusively localized on body sites continuously exposed to sunlight. Moreover, the ras mutations were all at or near dipyrimidine sites known to be targets of UV damage. Two primary tumors were biclonal with respect to ras mutation. An active role for UV irradiation in induction of the mutations is suggested.     

Human bone marrow cells positive for terminal deoxynucleotidyl transferase (TdT), HLA-DR, and a T cell marker may represent prothymocytes

Recent evidence suggests that prothymocytes, which occur in a low frequency in murine bone marrow (BM), are already committed to thymocyte differentiation and discrete from precursor B cells as well as pluripotent hematopoietic stem cells. Furthermore, it was suggested that, in rodents, prothymocytes are positive for the nuclear enzyme terminal deoxynucleotidyl transferase (TdT) and a T cell surface antigen. The human prothymocyte has not been identified as yet. We analyzed human BM cells by double immunofluorescence staining for TdT and the T cell surface markers Tp41 (recognized by the monoclonal antibodies WT1 and 3A1), T11, T1, and T6. In the BM samples tested, neither T1+/TdT+ nor T6+/TdT+ cells were detected, but Tp41+/TdT+ and T11+/TdT+ cells were present in low frequencies. In childhood BM, the frequency was about two to five in 10,000, whereas in adult BM and regenerating BM, these cells were not always detectable, but if detected, their frequency was five- to 10-fold lower. In a triple staining, using fluorescein, rhodamine, and colloidal gold particles as labels, it appeared that all Tp41+/TdT+ cells were also positive for HLA-DR. These Tp41+/HLA-DR+/TdT+ cells were also detectable in low frequencies in the thymus, and occasionally Tp41+/TdT+ and T11+/TdT+ cells were detected in the peripheral blood (PB), suggesting a migration from the BM to the thymus via the PB. The malignant counterpart of the Tp41+/HLA-DR+/TdT+ cell was detected in a patient with acute lymphoblastic leukemia with the Tp41+/T11+/HLA-DR+/TdT+/T1-/T6- phenotype and germ-line immunoglobulin heavy chain genes. We postulate that the Tp41+/T11+/HLA-DR+/TdT+/T1-/T6- cell represents a human prothymocyte.     

Rapid eco-friendly synthesis,characterization, and cytotoxic study of trimetallic stable nanomedicine: A potential material for biomedical applications

In the current scenario of the fight against cancer Integration of potential elements seems to be the best alternative since it overcomes the weaknesses of individuals and the combination of elements makes them formidable in the fight against the cancer war. Inspired by this objective and trusting our knowledge of paddy straw grown oyster mushroom, Pleurotus florida (Pf) mediated synthesis; a first-of-kind approach has been developed for the rapid synthesis of Au–Pt–Ag trimetallic nanoparticles (TMNPs). The developed method was successful, which was confirmed by Ultraviolet–Visible, X-ray diffraction, Transmission Electron Microscopy, Energy Dispersive Spectroscopy. Specifically, prepared TMNPs have been studied for their stability and size as a primary prerequisite for nanomedicine. Finally, the stable nanomedicine developed has been assessed for its performance against the highly metastatic breast cancer cell line (mda-mb-231). The performance was assessed using MTT assay and morphological readings, which were integrated with the cell viability data. We also determined the IC50 value, which was far superior to individual components and motivated us to postulate the possible breast cancer cell killing mechanism of TMNPs. The present study unlocks the new paths for the mushroom-mediated environmentally friendly, economic synthesis of trimetallic nanoparticles, which can be effectively used in cancer nanomedicine.