Evaluation of Solid-Phase Microextraction Desorption Parameters for Fast GC Analysis of Cocaine in Coca Leaves

By its simplicity and rapidity, solid-phase microextraction (SPME) appears as an interesting alternative for sample introduction in fast gas chromatography (fast GC). This combination depends on numerous parameters affecting the desorption step (i.e., the release of compounds from the SPME fiber coating to the GC column). In this study, different liner diameters, injection temperatures, and gas flow rates are evaluated to accelerate the thermal desorption process in the injection port. This process is followed with real-time direct coupling a split/splitless injector to a mass spectrometer by means of a short capillary. It is shown that an effective, quantitative, and rapid transfer of cocaine (COC) and cocaethylene (CE) is performed with a 0.75-mm i.d. liner, at 280°C and 4 mL/min gas flow rate. The 7-µm polydimethylsiloxane (PDMS) coating is selected for combination with fast GC because the 100- µm PDMS fiber presents some limitations caused by fiber bleeding. Finally, the developed SPME-fast GC method is applied to perform in less than 5 min, the quantitation of COC extracted from coca leaves by focused microwave-assisted extraction. An amount of 7.6 ± 0.5 mg of COC per gram of dry mass is found, which is in good agreement with previously published result

Long-term outcome following successful endoscopic closure of tracheo-oesophageal fistulas with two cardiac amplatzer septal occluders in a patient with oesophageal cancer.

Acquired tracheo-oesophageal fistulas (TEFs) are rare and challenging complications in the course of oesophageal cancer. While surgery is the only curative treatment option for TEFs many patients are not eligible for surgery. Endoscopic treatment approaches such as tracheal- and/or oesophageal- stenting are available, but associated with complications like the development of new fistulas and mucus retention. Off- label-use of cardiac amplatzer occluder devices to close TEFs has been reported in few case-reports with inconsistent short-term outcomes. We report a case of successful closure of two adjacent TEFs with two partially overlapping cardiac amplatzer occluder devices. The insertion of a 12 mm and a 9 mm device was successful and without complications. The patient tolerated the cardiac amplatzer-devices well and could resume oral food uptake after 2 months. Two years after closure, the patient remained free of symptoms suggesting complete sealing of the fistulas

Increasing awareness of climate change with immersive virtual reality

Previous research has shown that immersive virtual reality (VR) is a suitable tool for visualizing the consequences of climate change. The aim of the present study was to investigate whether visualization in VR has a stronger influence on climate change awareness and environmental attitudes compared to traditional media. Furthermore, it was examined how realistic a VR experience has to be in order to have an effect. The VR experience consisted of a model of the Aletsch glacier (Switzerland) melting over the course of 220 years. Explicit measurements (new environmental paradigm NEP, climate change scepticism, and nature relatedness) and an implicit measurement (implicit association test) were collected before and after the VR intervention and compared to three different non-VR control conditions (video, images with text, and plain text). In addition, the VR environment was varied in terms of degrees of realism and sophistication (3 conditions: abstract visualization, less sophisticated realistic visualization, more sophisticated realistic visualization). The six experimental conditions (3 VR conditions, three control conditions) were modeled as mixed effects, with VR versus control used as a fixed effect in a mixed effects modeling framework. Across all six conditions, environmental awareness (NEP) was higher after the participants (N = 142) had been confronted with the glacier melting, while no differences were found for nature relatedness and climate change scepticism before and after the interventions. There was no significant difference between VR and control conditions for any of the four measurements. Nevertheless, contrast analyses revealed that environmental awareness increased significantly only for the VR but not for the control conditions, suggesting that VR is more likely to lead to attitude change. Our results show that exposure to VR environments successfully increased environmental awareness independently of the design choices, suggesting that even abstract and less sophisticated VR environment designs may be sufficient to increase pro-environmental attitudes

Unraveling condition-dependent networks of transcription factors that control metabolic pathway activity in yeast

While typically many expression levels change in transcription factor mutants, only few of these changes lead to functional changes. The predictive capability of expression and DNA binding data for such functional changes in metabolism is very limited.Large-scale 13C-flux data reveal the condition specificity of transcriptional control of metabolic function.Transcription control in yeast focuses on the switch between respiration and fermentation.Follow-up modeling on the basis of transcriptomics and proteomics data suggest the newly discovered Gcn4 control of respiration to be mediated via PKA and Snf1

Ermittlung pflanzenbaulich relevanter Bodenkenndaten mit Hilfe ausgewählter Bodensensorik

Die Fachhochschule Osnabrück hat ein eigenes Bodensensorsystem für geo­elektrische Messungen im Oberboden entwickelt. Das verwendete Messprinzip ist die Erfassung des komplexen elektrischen Leitwerts mit einem Elektrodenpaar. Die Funktionsfähigkeit dieses Systems wird anhand von Vergleichen der Zusammen­hänge zwischen der elektrischen Leitfähig­keit und den Korngrößen sowie dem organischen Kohlenstoffgehalt mit zwei kommerziellen Systemen nachgewiesen. Weiter wird eine Methode vorgestellt, wie mit Hilfe der elektrischen Leitfähigkeit die räumliche Verteilung der Korngrößen­fraktion Ton abgeschätzt wird

SLC25A12 Missense Variant in Nova Scotia Duck Tolling Retrievers Affected by Cerebellar Degeneration—Myositis Complex (CDMC)

We investigated two litters of distantly related Nova Scotia Duck Tolling Retrievers (NSDTR), of which four puppies were affected by cerebellar signs with or without neuromuscular weakness. The phenotype was termed cerebellar degeneration—myositis complex (CDMC). We suspected a heritable condition and initiated a genetic analysis. The genome of one affected dog was sequenced and compared to 565 control genomes. This search yielded a private protein-changing SLC25A12 variant in the affected dog, XM_038584842.1:c.1337C>T, predicted to result in the amino acid change XP_038440770.1:(p.Pro446Leu). The genotypes at the variant co-segregated with the phenotype as expected for a monogenic autosomal recessive mode of inheritance in both litters. Genotyping of 533 additional NSDTR revealed variant allele frequencies of 3.6% and 1.3% in a European and a North American cohort, respectively. The available clinical and biochemical data, together with current knowledge about SLC25A12 variants and their functional impact in humans, mice, and dogs, suggest the p.Pro446Leu variant is a candidate causative defect for the observed phenotype in the affected dogs

Proline metabolism supports metastasis formation and could be inhibited to selectively target metastasizing cancer cells

Metastases are the leading cause of mortality in patients with cancer. Metastasis formation requires cancer cells to adapt their cellular phenotype. However, how metabolism supports this adaptation of cancer cells is poorly defined. We use 2D versus 3D cultivation to induce a shift in the cellular phenotype of breast cancer cells. We discover that proline catabolism via proline dehydrogenase (Prodh) supports growth of breast cancer cells in 3D culture. Subsequently, we link proline catabolism to in vivo metastasis formation. In particular, we find that PRODH expression and proline catabolism is increased in metastases compared to primary breast cancers of patients and mice. Moreover, inhibiting Prodh is sufficient to impair formation of lung metastases in the orthotopic 4T1 and EMT6.5 mouse models, without adverse effects on healthy tissue and organ function. In conclusion, we discover that Prodh is a potential drug target for inhibiting metastasis formation

Polysaccharide capsule composition of pneumococcal serotype 19A subtypes: Unaltered among subtypes and independent of the nutritional environment

Serotype 19A strains have emerged as a cause of invasive pneumococcal disease after the introduction of the seven-valent pneumococcal conjugate vaccine (PCV7) and serotype 19A has now been included in the recent thirteen-valent vaccine (PCV13). Genetic analysis has revealed at least three different capsular serotype 19A subtypes and nutritional environment dependent variation of the 19A capsule structure has been reported. Pneumococcal vaccine effectiveness and serotyping accuracy might be impaired by structural differences in serotype 19A capsules. We therefore analyzed the distribution of 19A subtypes collected within a Swiss national surveillance program and determined capsule composition in different nutritional conditions with high-performance liquid chromatography (HPLC), gas chromatography – mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR). After the introduction of PCV7 a significant relative increase of subtype 19A-II and decrease of 19A-I occurred. Chemical analyses showed no difference in the composition as well as the linkage of 19A subtype capsular saccharides grown in defined and undefined growth media being consistent with a trisaccharide repeat unit composed of rhamnose, N-acetyl-mannosamine and glucose. In summary, our study suggests that no structural variance dependent of the nutritional environment or the subtype exists. The serotype 19A subtype shift observed after the introduction of the PCV7 can therefore not be explained by selection of a capsule variant. However, capsule composition analysis of emerging 19A clones is recommended in cases where there is no other explanation for a selective advantage such as antibiotic resistance or loss or acquisition of other virulence factor

A full degree-of-freedom photonic crystal spatial light modulator

Harnessing the full complexity of optical fields requires complete control of all degrees-of-freedom within a region of space and time -- an open goal for present-day spatial light modulators (SLMs), active metasurfaces, and optical phased arrays. Here, we solve this challenge with a programmable photonic crystal cavity array enabled by four key advances: (i) near-unity vertical coupling to high-finesse microcavities through inverse design, (ii) scalable fabrication by optimized, 300 mm full-wafer processing, (iii) picometer-precision resonance alignment using automated, closed-loop "holographic trimming", and (iv) out-of-plane cavity control via a high-speed micro-LED array. Combining each, we demonstrate near-complete spatiotemporal control of a 64-resonator, two-dimensional SLM with nanosecond- and femtojoule-order switching. Simultaneously operating wavelength-scale modes near the space- and time-bandwidth limits, this work opens a new regime of programmability at the fundamental limits of multimode optical control.Comment: 25 pages, 20 figure