Carbophile Additionen von Organocupraten mit 1,3-Thiazol-5(4H)-thionen

Carbophilic Additions of Organocuprates and 1,3-Thiazole-5(4H)-thiones Organocuprates and 1,3-thiazole-5(4H)-thiones 1 react in THF at 0° via carbophilic addition onto the C? S bond to give 4,5-dihydro-1,3-thiazole-5-thiols 3 (Scheme 3). This observation is in marked contrast to the previously described reaction of organolithium compounds and 1 , which undergo a thiophilic addition onto the exocyclic S-atom. As an exception, treatment of the 1,3-thiazole-5(4H)-thione 1a with tert-butyl cuprate leads to 7a (Scheme 3).     

Synthesis of monodisperse polymers from proteins

Proteins are functional biopolymers; viewed as molecules, they are also monodisperse polyamides with chemically reactive side chains. This paper describes the use of proteins as starting materials for the synthesis of monodisperse polymers with nonbiological functionalities attached to the side chains. It demonstrates the complete derivatization of amine groups (lysine side chains and N-termini) on three different proteins by addition of activated carboxylate reagents in aqueous solutions containing sodium dedecyl sulfate (SDS), under denaturing conditions. Several different acylating reagents were used to generate derivatized proteins; the resulting compounds constitute a new class of monodisperse, semisynthetic polymers, having the potential for wide variation in the structure of the backbone and of the side chains. Modification of lysozyme on a gram scale demonstrated that the method can generate useful quantities of material.     

Synthesis and characterization of graphene-based nanocomposites with potential use for biomedical applications

In this paper, GaN nanoparticles were synthesized from the complex Ga(H₂NCONH₂)₆Cl₃ in the flow of NH₃ at a mild temperature (350 °C). Further purification was performed by the ethanol-thermal method. The ethanol-thermal method also prompted the GaN nanoparticles to grow into an anisotropic morphology. XRD patterns reveal that GaN nanoparticles have crystallized in a hexagonal wurtzite structure. TEM observation shows that the average size of the as-prepared nanoparticles is about 5–10 nm. The photoluminescence spectrum exhibits a broad green emission band with a peak at 510 nm. It can be known from the first-principle theoretic simulation by the TDDFT method that this fluorescence emission band is attributed to the hydride defects of V _N-H on the surface of GaN nanoparticles.     

Effects of lung volume on vertical larynx position during phonation

The vertical position of the larynx seems to be relevant to voicefunction. As a high vertical larynx position is often seen in hyperfunctional and strained voices, a lowering of a habitually elevated larynx is sometimes a specific goal in clinical voice therapy and different larynx-lowering exercises are used to achieve this goal. Earlier investigations have shown that pitch and to some extent also vocal loudness are relevant to vertical larynx position. In the present investigation, we examine if lung volume affects vertical larynx position. Using a multi-channel electroglottograph, the larynx position was measured in 29 healthy, vocally untrained subjects, who phonated at different lung volumes, pitches, and degrees of vocal loudness. The main results were that high lung volume was clearly associated with a lower larynx position as compared to low lung volume. In addition, vertical larynx position was strongly correlated with pitch. Both of these dependencies were shown to be stronger in males than in females. Our results suggest that lung volume is a factor that is highly relevant to larynx height in untrained subjects.     

Voice source characteristics in six premier country singers

Voice source characteristics as derived from inverse filtering were analyzed in 6 country singers' speech and singing. Results showed that the closed quotient varied systematically with vocal loudness, and that glottal compliance (the ratio between transglottal AC volume displacement and subglottal pressure) decreased with increases in fundamental frequency but remained unaffected by vocal loudness. No striking differences were found in source characteristics between speech and singing within subjects. The degree of phonatory press, as judged by a panel of 19 expert listeners, appeared related to the range in which the singer was singing and to the sound pressure level gain from a doubling of subglottal pressure.     

Detection of nanoparticles in edible plant tissues exposed to nano-copper using single-particle ICP-MS

The increasing use of nanopesticides has raised concerns about their effects on crop plants and the impact of human health as well as ecological effects. While increased uptake of metal ions has been observed before, to date, very few studies have demonstrated the presence of nanoparticles in edible tissues. Single-particle inductively coupled plasma–mass spectrometry (sp-ICP-MS) has been suggested as a powerful tool to detect inorganic nanoparticles (NPs) in environmental samples. Here, we exposed edible plant tissues from lettuce, kale, and collard green to nano-CuO, simulating its use as a nanopesticide. We applied sp-ICP-MS to demonstrate the presence of nanoparticles, both in the water used to rinse crop leaf surfaces exposed to nano-CuO and within the leaf tissues. Lettuces retained the highest amounts of nCuO NPs on the leaf surface, followed by collard green and then kale. Surface hydrophilicity and roughness of the leaf surfaces played an important role in retaining nano-CuO. The results indicate that most of the nanoparticles are removed via washing, but that a certain fraction is taken up by the leaves and can result in human exposure, albeit at low levels.

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Use of hyperpolarized [1-C]pyruvate and [2-C]pyruvate to probe the effects of the anticancer agent dichloroacetate on mitochondrial metabolism in vivo in the normal rat

Development of hyperpolarized technology utilizing dynamic nuclear polarization has enabled the measurement of ¹³C metabolism in vivo at very high signal-to-noise ratio (SNR). In vivo mitochondrial metabolism can, in principle, be monitored with pyruvate, which is catalyzed to acetyl-CoA via pyruvate dehydrogenase (PDH). The purpose of this work was to determine whether the compound sodium dichloroacetate (DCA) could aid the study of mitochondrial metabolism with hyperpolarized pyruvate. DCA stimulates PDH by inhibiting its inhibitor, pyruvate dehydrogenase kinase. In this work, hyperpolarized [1-¹³C]pyruvate and [2-¹³C]pyruvate were used to probe mitochondrial metabolism in normal rats. Increased conversion to bicarbonate (+ 181±69%, P=.025) was measured when [1-¹³C]pyruvate was injected after DCA administration, and increased glutamate (+ 74±23%, P=.004), acetoacetate (+ 504±281%, P=.009) and acetylcarnitine (+ 377±157%, P=.003) were detected when [2-¹³C]pyruvate was used.     

Prominin‐1‐Specific Binding Peptide‐Modified Apoferritin Nanoparticle Carrying Irinotecan as a Novel Radiosensitizer for Colorectal Cancer Stem‐Like Cells

Resistance of cancer stem cells to radiotherapy remains a major obstacle to successful cancer management. Prominin‐1 (PROM1) is a cancer stem cell marker. Nanoparticle (NP) chemotherapeutics preferentially accumulate in tumors and are able to target cancer and cancer stem‐like cells through cancer cell‐specific ligands, making them uniquely suited as radiosensitizers for chemoradiation therapy. Using a biocompatible apoferritin NP, a PROM1‐targeted NP carrying irinotecan (PROM1‐NP) is engineered. The synergistic effect of the NP and irradiation is evaluated in PROM1‐overexpressing HCT‐116 colorectal cancer cell lines in vitro and in vivo. PROM1‐NP has a size of 17.2 ± 0.2 nm and surface charge of ?13.5 ± 0.2 mV. It demonstrates higher intracellular uptake than nontargeted NP or irinotecan alone. Treatment with PROM1‐NPs decreases HCT‐116 cell proliferation in a dose‐ and time‐dependent manner. In vitro radiosensitization reveals that PROM1‐NP is significantly more effective as a radiosensitizer than nontargeted NP or irinotecan. HCT‐116 tumor xenograft growth is markedly slower following treatment with PROM1‐NP plus irradiation, suggesting that PROM1‐NP is more effective as a radiosensitizer than irinotecan and nontargeted NP in vivo. This study provides the first preclinical evidence of the effectiveness of PROM1‐targeted NP formulation of irinotecan as a radiosensitizer.     

Micromixing models for turbulent flows

In transported probability density function and filtered density function methods, micromixing models are required to close the molecular mixing term. The accuracy and computational efficiency of improved versions of the parameterized scalar profile (PSP) model are assessed and compared with commonly used mixing models such as Curl, modified Curl, interaction by exchange with the mean and Euclidean minimum spanning tree. Different generalizations of the PSP mixing model for spatially inhomogeneous flow configurations are presented. The selected test cases focus on molecular mixing and avoid interference with other models. Simulation results for a three-stream problem, involving two inert scalars, and a multi-scalar test case with mean-scalar-gradients are presented.     

PLD-assisted VLS growth of aligned ferrite nanorods, nanowires, and nanobelts-synthesis, and properties

We report here a systematic synthesis and characterization of aligned alpha-Fe2O3 (hematite), epsilon-Fe2O3, and Fe3O4 (magnetite) nanorods, nanobelts, and nanowires on alumina substrates using a pulsed laser deposition (PLD) method. The presence of spherical gold catalyst particles at the tips of the nanostructures indicates selective growth via the vapor-liquid-solid (VLS) mechanism. Through a series of experiments, we have produced a primitive "phase diagram" for growing these structures based on several designed pressure and temperature parameters. Transmission electron microscopy (TEM) analysis has shown that the rods, wires, and belts are single-crystalline and grow along <111>m or <110>h directions. X-ray diffraction (XRD) measurements confirm phase and structural analysis. Superconducting quantum interference device (SQUID) measurements show that the iron oxide structures exhibit interesting magnetic behavior, particularly at room temperature. This work is the first known report of magnetite 1D nanostructure growth via the vapor-liquid-solid (VLS) mechanism without using a template, as well as the first known synthesis of long epsilon-Fe2O3 nanobelts and nanowires.