Assessment and optimization of chemical industrial processes from a life cycle perspective

During the PhD program in chemistry, curriculum in environmental chemistry, at the University of Bologna the sustainability of industry was investigated through the application of the LCA methodology. The efforts were focused on the chemical sector in order to investigate reactions dealing with the Green Chemistry and Green Engineering principles, evaluating their sustainability in comparison with traditional pathways by a life cycle perspective. The environmental benefits associated with a reduction in the synthesis steps and the use of renewable feedstock were assessed through a holistic approach selecting two case studies with high relevance from an industrial point of view: the synthesis of acrylonitrile and the production of acrolein. The current approach wants to represent a standardized application of LCA methodology to the chemical sector, which could be extended to several case studies, and also an improvement of the current databases, since the lack of data to fill the inventories of the chemical productions represent a huge limitation, difficult to overcome and that can affects negatively the results of the studies. Results emerged from the analyses confirms that the sustainability in the chemical sector should be evaluated from a cradle-to-gate approach, considering all the stages and flows involved in each pathways in order to avoid shifting the environmental burdens from a steps to another. Moreover, if possible, LCA should be supported by other tools able to investigate the other two dimensions of sustainability represented by the social and economic issues.

Microbial ecology of biotechnological processes

The investigation of phylogenetic diversity and functionality of complex microbial communities in relation to changes in the environmental conditions represents a major challenge of microbial ecology research. Nowadays, particular attention is paid to microbial communities occurring at environmental sites contaminated by recalcitrant and toxic organic compounds. Extended research has evidenced that such communities evolve some metabolic abilities leading to the partial degradation or complete mineralization of the contaminants. Determination of such biodegradation potential can be the starting point for the development of cost effective biotechnological processes for the bioremediation of contaminated matrices. This work showed how metagenomics-based microbial ecology investigations supported the choice or the development of three different bioremediation strategies. First, PCR-DGGE and PCR-cloning approaches served the molecular characterization of microbial communities enriched through sequential development stages of an aerobic cometabolic process for the treatment of groundwater contaminated by chlorinated aliphatic hydrocarbons inside an immobilized-biomass packed bed bioreactor (PBR). In this case the analyses revealed homogeneous growth and structure of immobilized communities throughout the PBR and the occurrence of dominant microbial phylotypes of the genera Rhodococcus, Comamonas and Acidovorax, which probably drive the biodegradation process. The same molecular approaches were employed to characterize sludge microbial communities selected and enriched during the treatment of municipal wastewater coupled with the production of polyhydroxyalkanoates (PHA). Known PHA-accumulating microorganisms identified were affiliated with the genera Zooglea, Acidovorax and Hydrogenophaga. Finally, the molecular investigation concerned communities of polycyclic aromatic hydrocarbon (PAH) contaminated soil subjected to rhizoremediation with willow roots or fertilization-based treatments. The metabolic ability to biodegrade naphthalene, as a representative model for PAH, was assessed by means of stable isotope probing in combination with high-throughput sequencing analysis. The phylogenetic diversity of microbial populations able to derive carbon from naphthalene was evaluated as a function of the type of treatment.

Measurement of the pair production of b-jets in proton-proton collisions at root out s = 7 TeV with the ATLAS detector

In hadronischen Kollisionen entstehen bei einem Großteil der Ereignisse mit einem hohen Impulsübertrag Paare aus hochenergetischen Jets. Deren Produktion und Eigenschaften können mit hoher Genauigkeit durch die Störungstheorie in der Quantenchromodynamik (QCD) vorhergesagt werden. Die Produktion von \textit{bottom}-Quarks in solchen Kollisionen kann als Maßstab genutzt werden, um die Vorhersagen der QCD zu testen, da diese Quarks die Dynamik des Produktionsprozesses bei Skalen wieder spiegelt, in der eine Störungsrechnung ohne Einschränkungen möglich ist. Auf Grund der hohen Masse von Teilchen, die ein \textit{bottom}-Quark enthalten, erhält der gemessene, hadronische Zustand den größten Teil der Information von dem Produktionsprozess der Quarks. Weil sie eine große Produktionsrate besitzen, spielen sie und ihre Zerfallsprodukte eine wichtige Rolle als Untergrund in vielen Analysen, insbesondere in Suchen nach neuer Physik. In ihrer herausragenden Stellung in der dritten Quark-Generation könnten sich vermehrt Zeichen im Vergleich zu den leichteren Quarks für neue Phänomene zeigen. Daher ist die Untersuchung des Verhältnisses zwischen der Produktion von Jets, die solche \textit{bottom}-Quarks enthalten, auch bekannt als $b$-Jets, und aller nachgewiesener Jets ein wichtiger Indikator für neue massive Objekte. In dieser Arbeit werden die Produktionsrate und die Korrelationen von Paaren aus $b$-Jets bestimmt und nach ersten Hinweisen eines neuen massiven Teilchens, das bisher nicht im Standard-Modell enthalten ist, in dem invarianten Massenspektrum der $b$-Jets gesucht. Am Large Hadron Collider (LHC) kollidieren zwei Protonenstrahlen bei einer Schwerpunktsenergie von $\sqrt s = 7$ TeV, und es werden viele solcher Paare aus $b$-Jets produziert. Diese Analyse benutzt die aufgezeichneten Kollisionen des ATLAS-Detektors. Die integrierte Luminosität der verwendbaren Daten beläuft sich auf 34~pb$^{-1}$. $b$-Jets werden mit Hilfe ihrer langen Lebensdauer und den rekonstruierten, geladenen Zerfallsprodukten identifiziert. Für diese Analyse müssen insbesondere die Unterschiede im Verhalten von Jets, die aus leichten Objekten wie Gluonen und leichten Quarks hervorgehen, zu diesen $b$-Jets beachtet werden. Die Energieskala dieser $b$-Jets wird untersucht und die zusätzlichen Unsicherheit in der Energiemessung der Jets bestimmt. Effekte bei der Jet-Rekonstruktion im Detektor, die einzigartig für $b$-Jets sind, werden studiert, um letztlich diese Messung unabhängig vom Detektor und auf Niveau der Hadronen auswerten zu können. Hiernach wird die Messung zu Vorhersagen auf nächst-zu-führender Ordnung verglichen. Dabei stellt sich heraus, dass die Vorhersagen in Übereinstimmung zu den aufgenommenen Daten sind. Daraus lässt sich schließen, dass der zugrunde liegende Produktionsmechanismus auch in diesem neu erschlossenen Energiebereich am LHC gültig ist. Jedoch werden auch erste Hinweise auf Mängel in der Beschreibung der Eigenschaften dieser Ereignisse gefunden. Weiterhin können keine Anhaltspunkte für eine neue Resonanz, die in Paare aus $b$-Jets zerfällt, in dem invarianten Massenspektrum bis etwa 1.7~TeV gefunden werden. Für das Auftreten einer solchen Resonanz mit einer Gauß-förmigen Massenverteilung werden modell-unabhängige Grenzen berechnet.

Tailoring properties and functionalities of TiO2 and Ag nanoparticles involved in surfaces engineering processes

The functionalization of substrates through the application of nanostructured coatings allows to create new materials, with enhanced properties. In this work, the development of self-cleaning and antibacterial textiles, through the application of TiO2 and Ag based nanostructured coatings was carried out. The production of TiO2 and Ag functionalized materials was achieved both by the classical dip-padding-curing method and by the innovative electrospinning process to obtain nanofibers doped with nano-TiO2 and nano-Ag. In order to optimize the production of functionalized textiles, the study focused on the comprehension of mechanisms involved in the photocatalytic and antibacterial processes and on the real applicability of the products. In particular, a deep investigation on the relationship between nanosol physicochemical characteristics, nanocoating properties and their performances was accomplished. Self-cleaning textiles with optimized properties were obtained by properly purifying and applying commercial TiO2 nanosol while the studies on the photocatalytic mechanism operating in self-cleaning application demonstrated the strong influence of hydrophilic properties and of interaction surface/radicals on final performance. Moreover, a study about the safety in handling of nano-TiO2 was carried out and risk remediation strategies, based on “safety by design” approach, were developed. In particular, the coating of TiO2 nanoparticles by a SiO2 shell was demonstrated to be the best risk remediation strategy in term of biological response and preserving of photoreactivity. The obtained results were confirmed determining the reactive oxygen species production by a multiple approach. Antibacterial textiles for biotechnological applications were also studied and Ag-coated cotton materials, with significant anti-bacterial properties, were produced. Finally, composite nanofibers were obtained merging biopolymer processing and sol-gel techniques. Indeed, electrospun nanofibers embedded with TiO2 and Ag NPs, starting from aqueous keratin based formulation were produced and the photocatalytic and antibacterial properties were assessed. The results confirmed the capability of electrospun keratin nanofibers matrix to preserve nanoparticle properties.

New and More Sustainable Processes for the Synthesis of Phenolics: 2-phenoxyethanol and hydroxytyrosol

The research work has dealt with the study of new catalytic processes for the synthesis of fine chemicals belonging to the class of phenolics, namely 2-phenoxyethanol and hydroxytyrosol. The two synthetic procedures investigated have the advantages of being much closer to the Green Chemistry principles than those currently used industrially. In both cases, the challenge was that of finding catalysts and methods which led to the production of less waste, and used less hazardous chemicals, safer solvents, and reusable heterogeneous catalysts. In the case of 2-phenoxyethanol, the process investigated involves the use of ethylene carbonate (EC) as the reactant for phenol O-hydroxyethylation, in place of ethylene oxide. Besides being a safer reactant, the major advantage of using EC in the new synthesis is the better selectivity to the desired product achieved. Moreover, the solid catalyst based on Na-mordenite was fully recyclable. The reaction mechanism and the effect of the Si/Al ratio in the mordenite were investigated. In the case of hydroxytyrosol, which is one of the most powerful natural antioxidants, a new synthetic procedure was investigated; in fact, the method currently employed, the hydrolysis of oleuropein, an ester extracted from the waste water processing of the olive, makes use of large amounts of organic solvents (hexane, ethyl acetate), and involves several expensive steps of purification. The synthesis procedure set up involves first the reaction between catechol and 2,2-dimethoxyacetaldehyde, followed by the one-pot reduction of the intermediate to give the desired product. Both steps were optimized, in terms of catalyst used, and of reaction conditions, that allowed to reach ca 70% yield in each step. The reaction mechanism was investigated and elucidated. During a 3-month period spent at the University of Valencia (with Prof. A. Corma’s group), a process for the production of diesel additives (2,5-bis(propoxymethyl)furan) from fructose has been investigated.

Hunting for warped extra dimensions via loop-induced processes

This thesis is on loop-induced processes in theories with warped extra dimensions where the fermions and gauge bosons are allowed to propagate in the bulk, while the Higgs sector is localized on or near the infra-red brane. These so-called Randall-Sundrum (RS) models have the potential to simultaneously explain the hierarchy problem and address the question of what causes the large hierarchies in the fermion sector of the Standard Model (SM). The Kaluza-Klein (KK) excitations of the bulk fields can significantly affect the loop-level processes considered in this thesis and, hence, could indirectly indicate the existence of warped extra dimensions. The analytical part of this thesis deals with the detailed calculation of three loop-induced processes in the RS models in question: the Higgs production process via gluon fusion, the Higgs decay into two photons, and the flavor-changing neutral current b → sγ. A comprehensive, five-dimensional (5D) analysis will show that the amplitudes of the Higgs processes can be expressed in terms of integrals over 5D propagators with the Higgs-boson profile along the extra dimension, which can be used for arbitrary models with a compact extra dimension. To this end, both the boson and fermion propagators in a warped 5D background are derived. It will be shown that the seemingly contradictory results for the gluon fusion amplitude in the literature can be traced back to two distinguishable, not smoothly-connected incarnations of the RS model. The investigation of the b → sγ transition is performed in the KK decomposed theory. It will be argued that summing up the entire KK tower leads to a finite result, which can be well approximated by a closed, analytical expression.rnIn the phenomenological part of this thesis, the analytic results of all relevant Higgs couplings in the RS models in question are compared with current and in particular future sensitivities of the Large Hadron Collider (LHC) and the planned International Linear Collider. The latest LHC Higgs data is then used to exclude significant portions of the parameter space of each RS scenario. The analysis will demonstrate that especially the loop-induced Higgs couplings are sensitive to KK particles of the custodial RS model with masses in the multi tera-electronvolt range. Finally, the effect of the RS model on three flavor observables associated with the b → sγ transition are examined. In particular, we study the branching ratio of the inclusive decay B → X_s γ

Implementation of enhanced biological phosphorus removal (ebpr) wastewater treatment processes enriched with different microbial communities

The EBPR (Enhanced Biological Phosphorus Removal) is a type of secondary treatment in WWTPs (WasteWater Treatment Plants), quite largely used in full-scale plants worldwide. The phosphorus occurring in aquatic systems in high amounts can cause eutrophication and consequently the death of fauna and flora. A specific biomass is used in order to remove the phosphorus, the so-called PAOs (Polyphosphate Accumulating Organisms) that accumulate the phosphorus in form of polyphosphate in their cells. Some of these organisms, the so-called DPAO (Denitrifying Polyphosphate Accumulating Organisms) use as electron acceptor the nitrate or nitrite, contributing in this way also to the removal of these compounds from the wastewater, but there could be side reactions leading to the formation of nitrous oxides. The aim of this project was to simulate in laboratory scale a EBPR, acclimatizing and enriching the specialized biomass. Two bioreactors were operated as Sequencing Batch Reactors, one enriched in Accumulibacter, the other in Tetrasphaera (both PAOs): Tetrasphaera microorganisms are able to uptake aminoacids as carbon source, Accumulibacter uptake organic carbon (volatile fatty acids, VFA). In order to measure the removal of COD, phosphorus and nitrogen-derivate compounds, different analysis were performed: spectrophotometric measure of phosphorus, nitrate, nitrite and ammonia concentrations, TOC (Total Organic Carbon, measuring the carbon consumption), VFA via HPLC (High Performance Liquid Chromatography), total and volatile suspended solids following standard methods APHA, qualitative microorganism population via FISH (Fluorescence In Situ Hybridization). Batch test were also performed to monitor the NOx production. Both specialized populations accumulated as a result of SBR operations; however, Accumulibacter were found to uptake phosphates at higher extents. Both populations were able to remove efficiently nitrates and organic compounds occurring in the feeding. The experimental work was carried out at FCT of Universidade Nova de Lisboa (FCT-UNL) from February to July 2014.

Biogas and bio-hydrogen: production and uses. A review

The first part of this essay aims at investigating the already available and promising technologies for the biogas and bio-hydrogen production from anaerobic digestion of different organic substrates. One strives to show all the peculiarities of this complicate process, such as continuity, number of stages, moisture, biomass preservation and rate of feeding. The main outcome of this part is the awareness of the huge amount of reactor configurations, each of which suitable for a few types of substrate and circumstance. Among the most remarkable results, one may consider first of all the wet continuous stirred tank reactors (CSTR), right to face the high waste production rate in urbanised and industrialised areas. Then, there is the up-flow anaerobic sludge blanket reactor (UASB), aimed at the biomass preservation in case of highly heterogeneous feedstock, which can also be treated in a wise co-digestion scheme. On the other hand, smaller and scattered rural realities can be served by either wet low-rate digesters for homogeneous agricultural by-products (e.g. fixed-dome) or the cheap dry batch reactors for lignocellulose waste and energy crops (e.g. hybrid batch-UASB). The biological and technical aspects raised during the first chapters are later supported with bibliographic research on the important and multifarious large-scale applications the products of the anaerobic digestion may have. After the upgrading techniques, particular care was devoted to their importance as biofuels, highlighting a further and more flexible solution consisting in the reforming to syngas. Then, one shows the electricity generation and the associated heat conversion, stressing on the high potential of fuel cells (FC) as electricity converters. Last but not least, both the use as vehicle fuel and the injection into the gas pipes are considered as promising applications. The consideration of the still important issues of the bio-hydrogen management (e.g. storage and delivery) may lead to the conclusion that it would be far more challenging to implement than bio-methane, which can potentially “inherit” the assets of the similar fossil natural gas. Thanks to the gathered knowledge, one devotes a chapter to the energetic and financial study of a hybrid power system supplied by biogas and made of different pieces of equipment (natural gas thermocatalitic unit, molten carbonate fuel cell and combined-cycle gas turbine structure). A parallel analysis on a bio-methane-fed CCGT system is carried out in order to compare the two solutions. Both studies show that the apparent inconvenience of the hybrid system actually emphasises the importance of extending the computations to a broader reality, i.e. the upstream processes for the biofuel production and the environmental/social drawbacks due to fossil-derived emissions. Thanks to this “boundary widening”, one can realise the hidden benefits of the hybrid over the CCGT system.

Qualitatitive and quantitative analysis of fish spoilage processes for development of new food monitoring systems

This study investigates the growth and metabolite production of microorganisms causing spoilage of Atlantic cod (Gadus morhua) fillets packaged under air and modified atmosphere (60 % CO2, 40 % O2). Samples were provided by two different retailers (A and B). Storage of packaged fillets occurred at 4 °C and 8 °C. Microbiological quality and metabolite production of cod fillets stored in MAP 4 °C, MAP 8 °C and air were monitored during 13 days, 7 days and 3 days of storage, respectively. Volatile compounds concentration in the headspace were quantified by Selective ion flow tube mass spectrometry and a correlation with microbiological spoilage was studied. The onset of volatile compounds detection was observed to be mostly around 7 log cfu/g of total psychrotrophic count. Trimethylamine and dimethyl sulfide were found to be the dominant volatiles in all of the tested storage conditions, nevertheless there was no close correlation between concentrations of each main VOC and percentages of rejection based on sensory evaluation. According to results it was concluded that they cannot be considered as only indicators of the quality of cod fillets stored in modified atmosphere and air.  

Outdoor production of Isochrysis galbana (T-iso) in industrial scale photobioreactors and modelling of its photosynthesis and respiration rate

Isochrysis galbana is a widely-used strain in aquaculture in spite of its low productivity. To maximize the productivity of processes based on this microalgae strain, a model was developed considering the influence of irradiance, temperature, pH and dissolved oxygen concentration on the photosynthesis and respiration rate. Results demonstrate that this strain tolerates temperatures up to 35ºC but it is highly sensitive to irradiances higher than 500 µE·m-2·s-1 and dissolved oxygen concentrations higher than 11 mg·l-1. With the researcher group of the “Universidad de Almeria”, the developed model was validated using data from an industrial-scale outdoor tubular photobioreactor demonstrating that inadequate temperature and dissolved oxygen concentrations reduce productivity to half that which is maximal, according to light availability under real outdoor conditions. The developed model is a useful tool for managing working processes, especially in the development of new processes based on this strain and to take decisions regarding optimal control strategies. Also the outdoor production of Isochrysis galbana T-iso in industrial size tubular photobioreactors (3.0 m3) has been studied. Experiments were performed modifying the dilution rate and evaluating the biomass productivity and quality, in addition to the overall performance of the system. Results confirmed that T-iso can be produced outdoor at commercial scale in continuous mode, productivities up to 20 g·m-2·day-1 of biomass rich in proteins (45%) and lipids (25%) being obtained. The utilization of this type of photobioreactors allows controlling the contamination and pH of the cultures, but daily variation of solar radiation imposes the existence of inadequate dissolved oxygen concentration and temperature at which the cells are exposed to inside the reactor. Excessive dissolved oxygen reduced the biomass productivity to 68% of maximal, whereas inadequate temperature reduces to 63% of maximal. Thus, optimally controlling these parameters the biomass productivity can be duplicated. These results confirm the potential to produce this valuable strain at commercial scale in optimally designed/operated tubular photobioreactors as a biotechnological industry.

Absence of MyD88 results in enhanced TLR3-dependent phosphorylation of IRF3 and increased IFN-(beta) and RANTES production

Toll-like receptors are a group of pattern-recognition receptors that play a crucial role in "danger" recognition and induction of the innate immune response against bacterial and viral infections. TLR3 has emerged as a key sensor of viral dsRNA, resulting in the induction of the anti-viral molecule, IFN- . Thus, a clearer understanding of the biological processes that modulate TLR3 signaling is essential. Previous studies have shown that the TLR adaptor, Mal/TIRAP, an activator of TLR4, inhibits TLR3-mediated IFN- induction through a mechanism involving IRF7. In this study, we sought to investigate whether the TLR adaptor, MyD88, an activator of all TLRs except TLR3, has the ability to modulate TLR3 signaling. Although MyD88 does not significantly affect TLR3 ligand-induced TNF- induction, MyD88 negatively regulates TLR3-, but not TLR4-, mediated IFN- and RANTES production; this process is mechanistically distinct from that employed by Mal/TIRAP. We show that MyD88 inhibits IKK -, but not TBK1-, induced activation of IRF3. In doing so, MyD88 curtails TLR3 ligand-induced IFN- induction. The present study shows that while MyD88 activates all TLRs except TLR3, MyD88 also functions as a negative regulator of TLR3. Thus, MyD88 is essential in restricting TLR3 signaling, thereby protecting the host from unwanted immunopathologies associated with the excessive production of IFN- . Our study offers a new role for MyD88 in restricting TLR3 signaling through a hitherto unknown mechanism whereby MyD88 specifically impairs IKK -mediated induction of IRF3 and concomitant IFN- and RANTES production.

The sphingosine kinase 1 and S1P1 axis specifically counteracts LPS-induced IL-12p70 production in immune cells of the spleen

Sphingosine-1-phosphate (S1P) has been implicated in angiogenesis, inflammation, cancerogenesis, neurological excitability and immune regulation and is synthesized by two different sphingosine kinases (SphK). It was suggested that mice lacking the gene for SphK1 exhibit no obvious phenotype, because SphK2 compensates for its absence. However, recent investigations revealed that under challenge SphK1 contributed to pro-inflammatory processes favoring Th2 and Th17 rather than Th1-type reactions. To investigate the immune modulatory role of SphK1 as opposed to SphK2 specifically for the Th1 propagating IL-12p70 we compared WT and SphK1(-/-) splenocytes and Flt3-ligand differentiated BMCs of WT and SphK1(-/-), representing dendritic cells as major producers of IL-12p70, incubated with LPS. We determined the impact on IL-12p70 in comparison to other inflammatory cytokines, and on DC and macrophage surface marker expression, SphK mRNA, protein expression and enzymatic activity in splenocytes. Our data demonstrated that SphK1 deficiency enhanced LPS-induced IL-12p70 production although SphK2 was present. To further characterize SphK1-dependent IL-12p70 regulation we exogenously applied S1P, SEW2871 and the new potent S1P1 agonist CYM5442. Both S1P and S1P1-specific analogs fully compensated the increase of IL-12p70 production in SphK1-deficient splenocytes. The use of pertussis toxin, to block G(i)-coupled signaling downstream of S1P1, again increased IL-12p70 and neglected the compensation achieved by addition of S1P and S1P1 agonists pointing on the importance of this specific S1P-receptor. Given that, in parallel to a prominent IL-12p35 increase following LPS stimulation, LPS also enhanced SphK expression and total SphK activity, we concluded that SphK1-derived S1P acting via S1P1 is a major mechanism of this negative IL-12p70 feedback loop, which did not affect other cytokines. Moreover, our data showed that SphK2 activity failed to compensate for SphK1 deficiency. These findings clearly point to a divergent and cytokine-specific impact of immune cell SphK1 and SphK2 in chronic inflammation and cancer.

Effects of transcranial direct current stimulation (tDCS) on behaviour and electrophysiology of language production

Excitatory anodal transcranial direct current stimulation (A-tDCS) over the left dorsal prefrontal cortex (DPFC) has been shown to improve language production. The present study examined neurophysiological underpinnings of this effect. In a single-blinded within-subject design, we traced effects of A-tDCS compared to sham stimulation over the left DPFC using electrophysiological and behavioural correlates during overt picture naming. Online effects were examined during A-tDCS by employing the semantic interference (SI-)Effect – a marker that denotes the functional integrity of the language system. The behavioural SI-Effect was found to be reduced, whereas the electrophysiological SI-Effect was enhanced over left compared to right temporal scalp-electrode sites. This modulation is suggested to reflect a superior tuning of neural responses within language-related generators. After -(offline) effects of A-tDCS were detected in the delta frequency band, a marker of neural inhibition. After A-tDCS there was a reduction in delta activity during picture naming and the resting state, interpreted to indicate neural disinhibition. Together, these findings demonstrate electrophysiological modulations induced by A-tDCS of the left DPFC. They suggest that A-tDCS is capable of enhancing neural processes during and after application. The present functional and oscillatory neural markers could detect positive effects of prefrontal A-tDCS, which could be of use in the neuro-rehabilitation of frontal language functions.

Plant volatiles: production, function and pharmacology

Plant volatiles typically occur as a complex mixture of low-molecular weight lipophilic compounds derived from different biosynthetic pathways, and are seemingly produced as part of a defense strategy against biotic and abiotic stress, as well as contributing to various physiological functions of the producer organism. The biochemistry and molecular biology of plant volatiles is complex, and involves the interplay of several biochemical pathways and hundreds of genes. All plants are able to store and emit volatile organic compounds (VOCs), but the process shows remarkable genotypic variation and phenotypic plasticity. From a physiological standpoint, plant volatiles are involved in three critical processes, namely plant–plant interaction, the signaling between symbiotic organisms, and the attraction of pollinating insects. Their role in these ‘‘housekeeping’’ activities underlies agricultural applications that range from the search for sustainable methods for pest control to the production of flavors and fragrances. On the other hand, there is also growing evidence that VOCs are endowed with a range of biological activities in mammals, and that they represent a substantially under-exploited and still largely untapped source of novel drugs and drug leads. This review summarizes recent major developments in the study of biosynthesis, ecological functions and medicinal applications of plant VOCs.

Peer Review Processes for Transdisciplinary Articles: A Reflection on Journal's Practices

Publishing is an essential means of validation and communication of research. This is no different in transdisciplinary research, where publishing also aims at contributing to the development of society through sharing of knowledge. In the scientific world, authors need to disseminate and validate results, reflect on issues, and participate in debates. On the other hand, institutions and individuals are assessed according to their publication record – as probably the most influential of all current evaluation criteria. Occupying the space between article production and counting impact factors, journal editors and reviewers play an important role in defining and using rules to assess and improve the work submitted to them. Publishing transdisciplinary research poses specific challenges, in particular with regard to peer-review processes, as it addresses different knowledge communities with different value systems and purposes.