Lignocellulosic materials, such as forest, agriculture, and agroindustrial residues, are among the most important resources for biorefineries to provide fuels, chemicals, and materials in such a way ...to substitute for, at least in part, the role of petrochemistry in modern society. Most of these sustainable biorefinery products can be produced from plant polysaccharides (glucans, hemicelluloses, starch, and pectic materials) and lignin. In this scenario, cellulosic ethanol has been considered for decades as one of the most promising alternatives to mitigate fossil fuel dependence and carbon dioxide accumulation in the atmosphere. However, a pretreatment method is required to overcome the physical and chemical barriers that exist in the lignin–carbohydrate composite and to render most, if not all, of the plant cell wall components easily available for conversion into valuable products, including the fuel ethanol. Hence, pretreatment is a key step for an economically viable biorefinery. Successful pretreatment method must lead to partial or total separation of the lignocellulosic components, increasing the accessibility of holocellulose to enzymatic hydrolysis with the least inhibitory compounds being released for subsequent steps of enzymatic hydrolysis and fermentation. Each pretreatment technology has a different specificity against both carbohydrates and lignin and may or may not be efficient for different types of biomasses. Furthermore, it is also desirable to develop pretreatment methods with chemicals that are greener and effluent streams that have a lower impact on the environment. This paper provides an overview of the most important pretreatment methods available, including those that are based on the use of green solvents (supercritical fluids and ionic liquids).
Minor adjustments, major effects: Lignocellulosic materials are among the most important resources for biorefineries to provide fuels, chemicals, and materials as substitutes for petrochemistry in modern society. An overview of the most important pretreatment methods available to date, including those that are based on the use of green solvents (supercritical fluids and ionic liquids).
InSpeculative Blackness, André M. Carrington analyzes the highly racialized genre of speculative fiction-including science fiction, fantasy, and utopian works, along with their fan cultures-to ...illustrate the relationship between genre conventions in media and the meanings ascribed to blackness in the popular imagination.
Carrington's argument about authorship, fandom, and race in a genre that has been both marginalized and celebrated offers a black perspective on iconic works of science fiction. He examines the career of actor Nichelle Nichols, who portrayed the character Uhura in the originalStar Trektelevision series and later became a recruiter for NASA, and the spin-off seriesStar Trek: Deep Space Nine, set on a space station commanded by a black captain. He recovers a pivotal but overlooked moment in 1950s science fiction fandom in which readers and writers of fanzines confronted issues of race by dealing with a fictitious black fan writer and questioning the relevance of race to his ostensible contributions to the 'zines. Carrington mines the productions of Marvel comics and the black-owned comics publisher Milestone Media, particularly the representations of black sexuality in its flagship title,Icon. He also interrogates online fan fiction about black British women inBuffy the Vampire Slayerand the Harry Potter series.Throughout this nuanced analysis, Carrington theorizes the relationship between race and genre in cultural production, revealing new understandings of the significance of blackness in twentieth-century American literature and culture.
The use of ionic liquids (ILs) for biomass processing has attracted considerable attention recently as it provides distinct features for pre‐treated biomass and fractionated materials in comparison ...to conventional processes. Process intensification through integration of dissolution, fractionation, hydrolysis and/or conversion in one pot should be accomplished to maximise economic and technological feasibility. The possibility of using alternative ILs capable not only of dissolving and deconstructing selectively biomass but also of catalysing reactions simultaneously are a potential solution of this problem. In this Review a critical overview of the state of the art and perspectives of the hydrolysis and conversion of cellulose and lignocellulosic biomass using acidic ILs using no additional catalyst are provided. The efficiency of the process is mainly considered with regard to the hydrolysis and conversion yields obtained and the selectivity of each reaction. The process conditions can be easily tuned to obtain sugars and/or platform chemicals, such as furans and organic acids. On the other hand, product recovery from the IL and its purity are the main challenges for the acceptance of this technology as a feasible alternative to conventional processes.
Biomass with acidic ionic liquids: The unique ability of acidic ionic liquids (ILs) to catalyse lignocellulosic biomass without additional catalyst within the biorefinery approach has attracted considerable attention recently. The selective production of monosaccharides, furans and organic acids from biomass can be performed in a one‐pot process under specific conditions. The acidic properties of ILs play a crucial role in biomass processing. The product and IL recovery are the main challenges of this new technology.
A central motif in neuronal networks is convergence, linking several input neurons to one target neuron. In visual cortex, convergence renders target neurons responsive to complex stimuli. Yet, ...convergence typically sends multiple stimuli to a target, and the behaviorally relevant stimulus must be selected. We used two stimuli, activating separate electrocorticographic V1 sites, and both activating an electrocorticographic V4 site equally strongly. When one of those stimuli activated one V1 site, it gamma synchronized (60–80 Hz) to V4. When the two stimuli activated two V1 sites, primarily the relevant one gamma synchronized to V4. Frequency bands of gamma activities showed substantial overlap containing the band of interareal coherence. The relevant V1 site had its gamma peak frequency 2–3 Hz higher than the irrelevant V1 site and 4–6 Hz higher than V4. Gamma-mediated interareal influences were predominantly directed from V1 to V4. We propose that selective synchronization renders relevant input effective, thereby modulating effective connectivity.
► There is pronounced gamma-band synchronization between monkey areas V1 and V4 ► Area V4 gamma synchronizes selectively to the behaviorally relevant portion of V1 ► Relevant V1 gamma peaks 2–3 Hz above irrelevant V1 and 4–6 Hz above V4 gamma ► In the gamma band, V1 influences V4 more strongly than vice versa
Attention selects stimuli for routing to higher cortical areas. Bosman et al. show that when early visual cortex is activated by two stimuli, only the attentionally selected activity gamma synchronizes to higher visual cortex, implementing selective routing through selective interareal synchronization.
Cannabis sativa L. is an important herbaceous species originating from Central Asia, which has been used in folk medicine and as a source of textile fiber since the dawn of times. This fast-growing ...plant has recently seen a resurgence of interest because of its multi-purpose applications: it is indeed a treasure trove of phytochemicals and a rich source of both cellulosic and woody fibers. Equally highly interested in this plant are the pharmaceutical and construction sectors, since its metabolites show potent bioactivities on human health and its outer and inner stem tissues can be used to make bioplastics and concrete-like material, respectively. In this review, the rich spectrum of hemp phytochemicals is discussed by putting a special emphasis on molecules of industrial interest, including cannabinoids, terpenes and phenolic compounds, and their biosynthetic routes. Cannabinoids represent the most studied group of compounds, mainly due to their wide range of pharmaceutical effects in humans, including psychotropic activities. The therapeutic and commercial interests of some terpenes and phenolic compounds, and in particular stilbenoids and lignans, are also highlighted in view of the most recent literature data. Biotechnological avenues to enhance the production and bioactivity of hemp secondary metabolites are proposed by discussing the power of plant genetic engineering and tissue culture. In particular two systems are reviewed, i.e., cell suspension and hairy root cultures. Additionally, an entire section is devoted to hemp trichomes, in the light of their importance as phytochemical factories. Ultimately, prospects on the benefits linked to the use of the -omics technologies, such as metabolomics and transcriptomics to speed up the identification and the large-scale production of lead agents from bioengineered Cannabis cell culture, are presented.
This Perspective considers the influential notion of a canonical (cortical) microcircuit in light of recent theories about neuronal processing. Specifically, we conciliate quantitative studies of ...microcircuitry and the functional logic of neuronal computations. We revisit the established idea that message passing among hierarchical cortical areas implements a form of Bayesian inference—paying careful attention to the implications for intrinsic connections among neuronal populations. By deriving canonical forms for these computations, one can associate specific neuronal populations with specific computational roles. This analysis discloses a remarkable correspondence between the microcircuitry of the cortical column and the connectivity implied by predictive coding. Furthermore, it provides some intuitive insights into the functional asymmetries between feedforward and feedback connections and the characteristic frequencies over which they operate.
In this Perspective, Bastos et al. consider the notion of a cortical microcircuit in light of recent theories about neuronal processing, highlighting the remarkable correspondence between the microcircuitry of the cortical column and the connectivity implied by predictive coding.
Oscillatory neuronal activity may provide a mechanism for dynamic network coordination. Rhythmic neuronal interactions can be quantified using multiple metrics, each with their own advantages and ...disadvantages. This tutorial will review and summarize current analysis methods used in the field of invasive and non-invasive electrophysiology to study the dynamic connections between neuronal populations. First, we review metrics for functional connectivity, including coherence, phase synchronization, phase-slope index, and Granger causality, with the specific aim to provide an intuition for how these metrics work, as well as their quantitative definition. Next, we highlight a number of interpretational caveats and common pitfalls that can arise when performing functional connectivity analysis, including the common reference problem, the signal to noise ratio problem, the volume conduction problem, the common input problem, and the sample size bias problem. These pitfalls will be illustrated by presenting a set of MATLAB-scripts, which can be executed by the reader to simulate each of these potential problems. We discuss how these issues can be addressed using current methods.
Immigration often results in changes in family dynamics, and within this process of dynamic relational adjustment youth can be conceptualised as contested sites of culture and associated ...intergenerational conflicts. This paper considers the experiences of migrant youth in Greater Western Sydney, New South Wales, Australia using conflict as a useful lens through which to view issues of migrant youth identity and their sense of social connectedness, belonging, and agency. The aim of this study was twofold: 1) to explore how migrant youth cope with acculturative stress and intergenerational conflicts, and 2) to better understand the systemic and family-related factors that facilitate positive settlement experiences for migrant youth.
A total of 14 focus group discussions, comprising 164 people, were carried out in Greater Western Sydney, New South Wales, Australia. These focus groups targeted newly arrived migrant parents and young adults (aged 18-24) of African, Burmese, Nepalese, Indian, Afghani, Bangladeshi and Iraqi backgrounds. Each focus group was 1.5 hours in duration and was conducted by a team of three people (an experienced facilitator, an accredited interpreter/bilingual worker, and a note taker). Data were collected using a standard interview schedule, and an accredited interpreter/bilingual worker asked the questions in the appropriate language and translated participant responses into English.
The findings highlight how youth in new migrant families become contested sites of culture as they try to balance integration into the new culture while maintaining their originating country's cultural values. Two themes and four subthemes emerged from the analysis: Intergenerational acculturation gap (loss of family capital and intergenerational conflicts); and factors that successfully protected positive family values while still allowing young people to integrate (the legal system that disarm authoritarian parenting practices and family rules; and parental use of children's increased knowledge of the new environment to navigate their new environment). Migrant families conceptualised family capital as the social solidarity, influence, and control governing obligations and expectations, intergenerational knowledge transmission and information flow, social norms, and cultural identity. The loss of family capital was characterised by children's refusal to associate with or meet family members, preferring to be alone in their rooms and private space. Migrant youth find themselves caught between and negotiating two cultures, with unwanted negative consequences at the family level in the form of intergenerational conflicts. The new found freedom among children and their rapid transition into the Australian society gives children an increased sense of agency, which in turn threatens parental authority, allowing children to exercise three forms of power: increased assertiveness due to legal protection of children against any corporal punishment; and English language fluency and greater understanding of the functioning of Australian social institutions.
Our findings suggest the need for an inter-generational approach to healthy family dynamics within migrant communities when dealing with youth negotiating the complexity and sensitivity of forging their cultural identity.
Abstract Because physical inactivity and unhealthy diets are highly prevalent, there is a need for cost-effective interventions that can reach large populations. Electronic health (eHealth) and ...mobile health (mHealth) solutions have shown promising outcomes and have expanded rapidly in the past decade. The purpose of this report is to provide an overview of the state of the evidence for the use of eHealth and mHealth in improving physical activity and nutrition behaviors in general and special populations. The role of theory in eHealth and mHealth interventions is addressed, as are methodological issues. Key recommendations for future research in the field of eHealth and mHealth are provided.
Highlights • CTC considered delayed uni-directional and zero-phase bi-directional communication. • Recent studies show that inter-areal gamma coherence has a non-zero phase lag. • Therefore, ...feedforward and feedback communication likely use CTC separately. • Feedforward-input receiving and feedback-output sending neurons are separate. • Gamma dominates feedforward, beta dominates feedback communication.
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