Stelleninhaber geht – Wissen bleibt!

In Deutschland nimmt der Anteil älterer Arbeitnehmerinnen und Arbeitnehmer tendenziell zu. Deshalb muss sich die Bibliotheksleitung verstärkt auf das altersbedingte Ausscheiden älterer Arbeitnehmer einstellen. Eine langjährige Fachkraft verfügt über spezielles Erfahrungswissen im direkten Aufgabenfeld. Die Bibliotheksleitung muss den Transfer allen relevanten Wissens, dazu gehört das Erfahrungswissen, vom Stelleninhaber auf seinen Nachfolger ermöglichen und unterstützen. Am Beispiel der Universitätsbibliothek der Bergakademie Freiberg wird untersucht, wie das Wissensmanagement im Rahmen eines Stellenwechsels derzeit geregelt ist. Das geschieht mit Hilfe von Tiefeninterviews in verschiedenen Abteilungen. Die Auswertung der Interviews bildet die Basis für ein Konzept für das Wissensmanagement beim Stellenwechsel an der UB Freiberg. Das Konzept benennt u. a. Maßnahmen zur Identifikation des stellenbezogenen Wissens, Maßnahmen zur Dokumentation des relevanten Wissens und Instrumente zur Wissensweitergabe beim Stellenwechsel

Ionic Liquid-Supported Aldehyde: A Highly Efficient Scavenger for Primary Amines

Novel aldehyde-functionalized ionic liquids have been synthesized and used as scavengers for primary amines in the synthesis of secondary amines. The yields of secondary amines are high (82–90%) with high purity. The advantages of the protocol over that with a polymer-supported aldehyde scavenger are the shorter reaction time, the homogeneous reaction medium, the high level of loading of the aldehyde group, easy monitoring of reaction, and characterization of intermediates

Probing the Mechanism of Baylis-Hillman Reaction in Ionic Liquids

The kinetic data for a Baylis-Hillman reaction in certain ionic liquids possessing ethylsulfate anion [EtSO₄]⁻ demonstrate that the rate determining step (RDS) is second order in aldehyde, but first order in acrylate and DABCO. This observation is similar to the one made by McQuade et al., who carried out this reaction in an aprotic polar solvent like DMSO. However, this is in contrast to the general observation that RDS is first order in aldehyde, acrylate, and DABCO in organic solvents

HIV-1 Vpr time-dependently induces IL-6 and IL-8 in astrocytes.

<p>SVGA astrocytes were seeded in 6 well plates and transfected with a plasmid encoding HIV-1 Vpr or were mock-transfected. The cells were harvested at 1, 3, 6, 12, 24, 48 and 72h post-transfection followed by the determination of IL-6 and IL-8 mRNA expression levels using real-time RT-PCR. The cell culture supernatants were also collected at 6, 12, 24, 48 and 72h post-transfection, and protein concentration of IL-6 and IL-8 was determined using BioPlex multi-cytokine assay. <b>(A, C)</b> mRNA expression levels of IL-6 and IL-8 calculated relative to mock-transfected controls, respectively. <b>(B, D)</b> protein concentration for secreted IL-6 and IL-8 in cell culture supernatants, respectively. <b>(E)</b> Expression of Vpr in SVGA astrocytes using western blotting. <b>(F)</b> Expression of GFP-Vpr in SVGA and primary astrocytes using fluorescent microscopy. <b>(G, H)</b> dose-dependent induction of IL-6 and IL-8 by HIV-1 Vpr plasmid in SVGA astrocytes. <b>(I, J)</b> depicts the mRNA expression levels, while <b>(K, L)</b> shows the secreted protein levels of IL-6 and IL-8 in human fetal astrocytes by HIV-1 Vpr electroporation, respectively. Every bar represents the mean ± SE of three independent experiments done in triplicates. Statistical analyses were performed using 1-way ANOVA using post-hoc Tukey HSD test, ** p < 0.01 and * p < 0.05.</p

Ionic Liquid-Supported Aldehyde: A Highly Efficient Scavenger for Primary Amines

Novel aldehyde-functionalized ionic liquids have been synthesized and used as scavengers for primary amines in the synthesis of secondary amines. The yields of secondary amines are high (82–90%) with high purity. The advantages of the protocol over that with a polymer-supported aldehyde scavenger are the shorter reaction time, the homogeneous reaction medium, the high level of loading of the aldehyde group, easy monitoring of reaction, and characterization of intermediates

Elucidation of Ionic Interactions in the Protic Ionic Liquid Solutions by Isothermal Titration Calorimetry

The strong hydrogen-bonded network noted in protic ionic liquids (PILs) may lead to stronger interactions of the ionic entities of PILs with solvents (water, methanol, ethylene glycol, dimethylsulfoxide (DMSO), <i>N</i>,<i>N</i>′-dimethylformamide (DMF)) as compared with those of aprotic ionic liquids (APILs). The PILs used in this work are 1-methylimidazolium tetrafluoroborate, 2-methylpyridinium tetrafluoroborate, and <i>N-</i>methylpyrrolodinium tetrafluoroborate in comparison to 1-butyl-3-methylimidazolium tetrafluoroborate, which is classified as an APIL. In this work, the excess partial molar enthalpy, <i>H</i>^E_IL obtained from isothermal calorimetric titrations at 298.15 K is used to probe the nature of interactions of the PIL cations with solvent molecules against those present in APIL–solvent systems. This work also reports interesting flip-flopping in the thermal behavior of these PIL–solvent systems depending upon the structure of the cationic ring of a PIL. In some cases, these flip-flops are the specific fingerprints for specific PILs in a common solvent environment. The excess partial molar enthalpy at infinite dilution, <i>H</i>^E,<i>∞</i>_IL, of these PILs bears a critical dependence on the solvent properties. An analysis of relative apparent molar enthalpies, ϕ_L, of the PIL solutions by the ion interaction model of Pitzer yields important information on ionic interactions of these systems

Why Does Water Accelerate Organic Reactions under Heterogeneous Condition?

An exhaustive kinetic analysis has been carried out to offer the convincing evidence of the involvement of the oil–water interface in guiding “on water organic reaction” mechanism. We have tuned the interface to prove its indispensable efficacy to make on water reaction a unique type among water mediated organic reactions. Sensitive techniques have established the preferential solvation of polarizable ions at the water surface. The experimental methods have been developed to control the molecular structure of oil–water interface in situ. Temperature-dependent analyses have also been presented to understand the enthalpic and entropic modifications of the interfacial water molecules during a heterogeneous reaction. Both of our kinetic and thermodynamic outcomes have univocally established that the hydrogen-bonding ability of the surface water molecules plays a critical role in deciding the on water organic reaction mechanism. The results have important implications on understanding the role of small water molecules adjacent to the reactants during the reactions discussed in this investigation

Synthesis of Chitosan-Mediated Silver Coated γ‑Fe₂O₃ (Ag−γ-Fe₂O₃@Cs) Superparamagnetic Binary Nanohybrids for Multifunctional Applications

The coating of chitosan on γ-Fe₂O₃ (IO) nanoparticles (NPs) produces the biocompatible nanohybrids (CIO) with enhanced functionalities and optical features associated with a reduction in the average size of IO nanoclusters from 11.3 to 9.3 nm as was estimated by transmission electron microscopy (TEM). The effective capping by chitosan was shown by X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), TEM, and Brunauer–Emmett–Teller (BET) analyses. The <i>in situ</i> generation of Ag on the surface of CIO displays characteristic surface plasmonic resonance band resulting in a further decrease in the average size of IO nanoclusters in these binary nanohybrids (CIOMAg) to 8.1 nm involving supramolecular binding through IO and chitosan functionalities. The identification of the phases of iron oxide and Ag NPs and the effective capping of chitosan in binary nanohybrids have been analyzed by XRD, AFM, FESEM, and infrared (IR) analyses. The phase of iron oxide and the presence of Ag NPs in the binary nanohybrids are evidently revealed by X-ray photoelectron spectroscopy (XPS) analysis and also supported by Raman spectroscopy. The interactions among IO, chitosan, and Ag moieties in the binary nanohybrids have been analyzed by IR and XPS. These binary nanohybrids demonstrated superparamagnetic behavior with relatively higher saturation magnetization (72.5–75.5 emu/g) at room temperature compared to those of CIO (69.2 emu/g), which provides an important feature for their catalytic, SERS, and biomedical applications. As-synthesized binary nanohybrids exhibited fairly high catalytic efficiency for the reduction of methyl orange even at low Ag concentration (30 nM) and could be recycled up to ten cycles without any loss of efficiency. It demonstrated the antibacterial activity for model bacteria <i>E. coli</i> with MIC and MBC at 1.1 and 4.2 μg/mL Ag, respectively, and SERS activity for model dye <i>p</i>-ATP with a detection limit at 10 pM, evidently suggesting their environmental and biomedical potential

Supramolecular-Assisted RNA-Templated Fluorescing Colloidal CdSe QDs Organized in Porous Morphology in the Presence of 1,3-Diaminopropane: Study of Their Multifunctional Behavior

The synthesis of colloidal CdSe nanostructures mediated by ribonucleic acid (RNA) in the presence of 1,3-diaminopropane (DAP) and excess Cd²⁺ produces CdSe QDs (average diameter, 4.5 nm) forming a chainlike morphology (SP1-DAP) with fairly high fluorescence efficiency and average lifetime (⟨τ⟩): 36% and 121 ns (λ_flu,sh = 650 nm), respectively. The addition of DAP induces its transformation to porous morphology in the process of self-assembly (SP1A-DAP), as evidenced by atomic force microscopy and transmission electron microscopy, and increase in rotational time constant from 14.7 to 31.5 ns. These changes are associated with a blue shift in emission maxima from 545 to 530 nm and an increase in ⟨τ⟩ from 102 to 111 ns (λ_max,flu = 545 nm). For SP1A-DAP, the development of distinct bands (cm^–1) in IR analysis (1240 (s) and 1183 (sh)), blue shift in positive peak at 271.1 nm in circular dichroism spectra, and changes in ¹H and ³¹P NMR spectra indicating RNA configuration change from C2′-endo to C3′-endo, clearly demonstrating the interaction of excess Cd²⁺ on RNA strand through −NH₂ in the process of self-assembly, lead to a change in configuration from B to A form. These nanostructures could selectively detect Hg²⁺ ions at ≥0.5 nM, as was followed by quenching of fluorescence, obeying both dynamic (<i>k</i>_q = 1.5 × 10¹² mol^–1 dm³ s^–1) and static mechanisms. Hg²⁺ ions get bound to SP1-DAP (<i>K</i>_a = 1.4 × 10⁸ mol^–1 dm³) and SP1A-DAP (<i>K</i>_a = 6.8 × 10⁷ mol^–1 dm³) involving −NH₂. <i>I</i>–<i>V</i> studies of the drop-cast films of SP1-DAP and SP1A-DAP exhibited the rectifying behavior, from which the <i>I</i>_Light/<i>I</i>_Dark (<i>I</i>_L/<i>I</i>_D) values have been computed to be 10 and 12.5, respectively, under forward bias condition. Interestingly, the synthesis of RNA-mediated CdSe nanohybrids in the presence of DAP produces fluorescing porous nanostructures displaying novel electronic and electrical behaviors, suggesting their future technological potential for fluorescence imaging, sensing, and optoelectronic devices

Multiple Protein Kinases via Activation of Transcription Factors NF-κB, AP-1 and C/EBP-δ Regulate the IL-6/IL-8 Production by HIV-1 Vpr in Astrocytes

<div><p>Neurocognitive impairments affect a substantial population of HIV-1 infected individuals despite the success of anti-retroviral therapy in controlling viral replication. Astrocytes are emerging as a crucial cell type that might be playing a very important role in the persistence of neuroinflammation seen in patients suffering from HIV-1 associated neurocognitive disorders. HIV-1 viral proteins including Vpr exert neurotoxicity through direct and indirect mechanisms. Induction of IL-8 in microglial cells has been shown as one of the indirect mechanism through which Vpr reduces neuronal survival. We show that HIV-1 Vpr induces IL-6 and IL-8 in astrocytes in a time-dependent manner. Additional experiments utilizing chemical inhibitors and siRNA revealed that HIV-1 Vpr activates transcription factors NF-κB, AP-1 and C/EBP-δ via upstream protein kinases PI3K/Akt, p38-MAPK and Jnk-MAPK leading to the induction of IL-6 and IL-8 in astrocytes. We demonstrate that one of the mechanism for neuroinflammation seen in HIV-1 infected individuals involves induction of IL-6 and IL-8 by Vpr in astrocytes. Understanding the molecular pathways involved in the HIV-1 neuroinflammation would be helpful in the design of adjunct therapy to ameliorate some of the symptoms associated with HIV-1 neuropathogenesis.</p></div