Past and future carbon fluxes from land use change, shifting cultivation and wood harvest

Carbon emissions from anthropogenic land use (LU) and land use change (LUC) are quantified with a Dynamic Global Vegetation Model for the past and the 21st century following Representative Concentration Pathways (RCPs). Wood harvesting and parallel abandonment and expansion of agricultural land in areas of shifting cultivation are explicitly simulated (gross LUC) based on the Land Use Harmonization (LUH) dataset and a proposed alternative method that relies on minimum input data and generically accounts for gross LUC. Cumulative global LUC emissions are 72 GtC by 1850 and 243 GtC by 2004 and 27–151 GtC for the next 95 yr following the different RCP scenarios. The alternative method reproduces results based on LUH data with full transition information within <0.1 GtC/yr over the last decades and bears potential for applications in combination with other LU scenarios. In the last decade, shifting cultivation and wood harvest within remaining forests including slash each contributed 19% to the mean annual emissions of 1.2 GtC/yr. These factors, in combination with amplification effects under elevated CO2, contribute substantially to future emissions from LUC in all RCPs.

Study of mineral dust entrainment in the planetary boundary layer by lidar depolarisation technique

Measurements on 27 June 2011 were performed over the Southern Iberian Peninsula at Granada EARLINET station, using active and passive remote sensing and airborne and surface in-situ data in order to study the entrainment processes between aerosols in the free troposphere and those in the planetary boundary layer (PBL). To this aim the temporal evolution of the lidar depolarisation, backscatter-related Angström exponent and potential temperature profiles were used in combination with the PBL contribution to the aerosol optical depth (AOD). Our results show that the mineral dust entrainment in the PBL was caused by the convective processes which ‘trapped’ the lofted mineral dust layer, distributing the mineral dust particles within the PBL. The temporal evolution of ground-based in-situ data evidenced the impact of this process at surface level. Finally, the amount of mineral dust in the atmospheric column available to be dispersed into the PBL was estimated by means of POLIPHON (Polarizing Lidar Photometer Networking). The dust mass concentration derived from POLIPHON was compared with the coarse-mode mass concentration retrieved with airborne in-situ measurements. Comparison shows differences below 50 µg/m³ (30% relative difference) indicating a relative good agreement between both techniques.

Low-cost disposable ALT electrochemical microsensors for in-vitro hepatotoxic assessment

Liver-on-chip systems are widely seen as having the potential to replace animal testing for long-term liver toxicity assessments. However, such systems necessitate solutions, such as electrochemical microsensors, to provide information about the cells exposed to chemical compounds in a confined space. This study describes the development of microsensors for the detection of alanine-aminotransferase (ALT), an intracellular enzyme found in hepatocytes, for monitoring the viability of in-vitro hepatic cell cultures. The electrochemical sensors were developed by using screen printed electrodes functionalized by drop-casting. These technologies are intended to produce disposable and low-cost sensors that can easily be exchanged once their performance is degraded. The sensors are capable of measuring ALT in a microfluidic environment through the detection of changes in glutamate concentration. The microsensors were found to be stable for more than 60 days and were successfully tested using hepatocellular lysates to assess their capability to quantify ALT activity in a hepatic cell culture. These results open the way to their integration in liver bioreactors to assess hepatocellular toxicity in-vitro.

Adenosine Kinase of T. b. Rhodesiense identified as the putative target of 4-[5-(4-phenoxyphenyl)-2H-pyrazol-3-yl]morpholine using chemical proteomics

BACKGROUND: Human African trypanosomiasis (HAT), a major parasitic disease spread in Africa, urgently needs novel targets and new efficacious chemotherapeutic agents. Recently, we discovered that 4-[5-(4-phenoxyphenyl)-2H-pyrazol-3-yl]morpholine (compound 1) exhibits specific antitrypanosomal activity with an IC(50) of 1.0 microM on Trypanosoma brucei rhodesiense (T. b. rhodesiense), the causative agent of the acute form of HAT. METHODOLOGY/PRINCIPAL FINDINGS: In this work we show adenosine kinase of T. b. rhodesiense (TbrAK), a key enzyme of the parasite purine salvage pathway which is vital for parasite survival, to be the putative intracellular target of compound 1 using a chemical proteomics approach. This finding was confirmed by RNA interference experiments showing that down-regulation of adenosine kinase counteracts compound 1 activity. Further chemical validation demonstrated that compound 1 interacts specifically and tightly with TbrAK with nanomolar affinity, and in vitro activity measurements showed that compound 1 is an enhancer of TbrAK activity. The subsequent kinetic analysis provided strong evidence that the observed hyperactivation of TbrAK is due to the abolishment of the intrinsic substrate-inhibition. CONCLUSIONS/SIGNIFICANCE: The results suggest that TbrAK is the putative target of this compound, and that hyperactivation of TbrAK may represent a novel therapeutic strategy for the development of trypanocides.

Role of catechol in the radical reduction of B-alkylcatecholboranes in presence of methanol

Mechanistic investigations on the previously reported reduction of B-alkylcatecholboranes in the presence of methanol led to the disclosure of a new mechanism involving catechol as a reducing agent. More than just revising the mechanism of this reaction, we disclose here the surprising role of catechol, a chain breaking antioxidant, which becomes a source of hydrogen atoms in an efficient radical chain process

[Dysfunction of the chemical senses smell and taste]

Dysfunction of the senses of taste and smell may strongly affect our lives. During the last years reliable techniques for the standardized investigation of the 2 senses have been introduced to clinical routine. These techniques are highly standardized and can be easily used, for example, for quality control before and after surgery. Although there are proven therapeutic approaches to taste or smell loss, by far not all patients can be helped. New ideas need to tested within rigorous double-blind studies. The regenerative capacity within the chemical senses provides a major basis for hopes on therapeutic success.

Stereoselective synthesis of 12,13-cyclopropyl-epothilone B and side-chain-modified variants

A general strategy has been devised for the stereoselective synthesis of 12,13-cyclopropyl-epothilone B and side-chain-modified variants thereof, which relies on late stage introduction of the heterocycle through Wittig olefination of ketone 14. Formation of the macrocycle was achieved through RCM-based ring closure and introduction of the cyclopropane moiety involved a highly selective Charette cyclopropanation of allylic alcohol 7.

Vibronic Spectra of Jet-Cooled 2-Aminopurine center dot H2O Clusters Studied by UV Resonant Two-Photon Ionization Spectroscopy and Quantum Chemical Calculations

For understanding the major- and minor-groove hydration patterns of DNAs and RNAs, it is important to understand the local solvation of individual nucleobases at the molecular level. We have investigated the 2-aminopurine center dot H2O. monohydrate by two-color resonant two-photon ionization and UV/UV hole-burning spectroscopies, which reveal two isomers, denoted A and B. The electronic spectral shift delta nu of the S-1 <- S-0 transition relative to bare 9H-2-aminopurine (9H-2AP) is small for isomer A (-70 cm(-1)), while that of isomer B is much larger (delta nu = 889 cm(-1)). B3LYP geometry optimizations with the TZVP basis set predict four cluster isomers, of which three are doubly H-bonded, with H2O acting as an acceptor to a N-H or -NH2 group and as a donor to either of the pyrimidine N sites. The "sugar-edge" isomer A is calculated to be the most stable form with binding energy D-e = 56.4 kJ/mol. Isomers B and C are H-bonded between the -NH2 group and pyrimidine moieties and are 2.5 and 6.9 kJ/mol less stable, respectively. Time-dependent (TD) B3LYP/TZVP calculations predict the adiabatic energies of the lowest (1)pi pi* states of A and B in excellent agreement with the observed 0(0)(0) bands; also, the relative intensities of the A and B origin bands agree well with the calculated S-0 state relative energies. This allows unequivocal identification of the isomers. The R2PI spectra of 9H-2AP and of isomer A exhibit intense low-frequency out-of-plane overtone and combination bands, which is interpreted as a coupling of the optically excited (1)pi pi* state to the lower-lying (1)n pi* dark state. In contrast, these overtone and combination bands are much weaker for isomer B, implying that the (1)pi pi* state of B is planar and decoupled from the (1)n pi* state. These observations agree with the calculations, which predict the (1)n pi* above the (1)pi pi* state for isomer B but below the (1)pi pi* for both 9H-2AP and isomer A.

Applying chemical stimuli on feathers to reduce feather pecking in laying hens

Recent studies have shown that spraying a distasteful substance (quinine) on a bird's feather cover reduced short-term feather pecking. The present experiment evaluated if other substances offer similar or better protection against feather pecking.;One hundred and twenty birds were divided into 12 groups of 10 birds each. Over a period of 10 days the birds' response to 10 feathers coated with one of the 11 distasteful substances was observed and recorded. Feathers were soaked in a 1% garlic solution, 1% almond oil, 1% clove oil, 1% clove solution, quinine sulphate solution in four concentrations (0.1%, 1%, 2%, 4%), 0.6 mol magnesium chloride solution, anti-peck spray or an angostura solution. The control group received uncoated feathers. The number of feathers plucked, rejected or eaten was counted 60 min after presenting the feathers. All substances reduced feather plucking (p < 0.0001) and consumption (p < 0.0001) significantly, compared to uncoated feathers. Quinine concentrations of 2% and 4% were most effective. This study was the first to investigate the aversive potential of different substances to deter feather peckers from the feathers of other birds. The findings may be useful in the development of spraying devices to prevent feather pecking when other management tools fail. (c) 2011 Elsevier B.V. All rights reserved.

Evaluation of the chemical residue monitoring in animal-derived products in Switzerland

This paper evaluates whether the Swiss monitoring programme for foreign substances in animal products fulfils basic epidemiological quality requirements, and identifies possible sources of bias in the selection of samples. The sampling was analysed over a 4-year period (2002-05). The sampling frame in 37 participating abattoirs covered 51% of all slaughtered pigs, 73% of calves, 68% of beef and 36% of cows. The analysis revealed that some sub-populations as defined by the region of origin were statistically over-represented while others were under-represented. The programme that is in accordance with European Union requirements contained some relevant bias. Patterns of under-sampled regions characterized by management type differences were identified. This could lead to an underestimate of the number of contaminated animals within the programme. Although the current sampling was stratified and partially risk-based, its efficiency could be improved by adopting a more targeted approach.