There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

2.3. Evaluation of Photocatalytic Water Splitting 6507 2.3.1. Photocatalytic Activity 6507 2.3.2. Photocatalytic Stability 6507 3. UV-Active Photocatalysts for Water Splitting 6507 3.1. d0 Metal Oxide Photocatalyts 6507 3.1.1. Ti-, Zr-Based Oxides 6507 3.1.2. Nb-, Ta-Based Oxides 6514 3.1.3. W-, Mo-Based Oxides 6517 3.1.4. Other d0 Metal Oxides 6518 3.2. d10 Metal Oxide Photocatalyts 6518 3.3. f0 Metal Oxide Photocatalysts 6518 3.4. Nonoxide Photocatalysts 6518 4. Approaches to Modifying the Electronic Band Structure for Visible-Light Harvesting 6519

Semiconductor-based Photocatalytic Hydrogen Generation

This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references).

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Cellulose nanomaterials review: structure, properties and nanocomposites

Cellulose constitutes the most abundant renewable polymer resource available today. As a chemical raw material, it is generally well-known that it has been used in the form of fibers or derivatives for nearly 150 years for a wide spectrum of products and materials in daily life. What has not been known until relatively recently is that when cellulose fibers are subjected to acid hydrolysis, the fibers yield defect-free, rod-like crystalline residues. Cellulose nanocrystals (CNs) have garnered in the materials community a tremendous level of attention that does not appear to be relenting. These biopolymeric assemblies warrant such attention not only because of their unsurpassed quintessential physical and chemical properties (as will become evident in the review) but also because of their inherent renewability and sustainability in addition to their abundance. They have been the subject of a wide array of research efforts as reinforcing agents in nanocomposites due to their low cost, availability, renewability, light weight, nanoscale dimension, and unique morphology. Indeed, CNs are the fundamental constitutive polymeric motifs of macroscopic cellulosic-based fibers whose sheer volume dwarfs any known natural or synthetic biomaterial. Biopolymers such as cellulose and lignin and † North Carolina State University. ‡ Helsinki University of Technology. Dr. Youssef Habibi is a research assistant professor at the Department of Forest Biomaterials at North Carolina State University. He received his Ph.D. in 2004 in organic chemistry from Joseph Fourier University (Grenoble, France) jointly with CERMAV (Centre de Recherche sur les Macromolecules Vegetales) and Cadi Ayyad University (Marrakesh, Morocco). During his Ph.D., he worked on the structural characterization of cell wall polysaccharides and also performed surface chemical modification, mainly TEMPO-mediated oxidation, of crystalline polysaccharides, as well as their nanocrystals. Prior to joining NCSU, he worked as assistant professor at the French Engineering School of Paper, Printing and Biomaterials (PAGORA, Grenoble Institute of Technology, France) on the development of biodegradable nanocomposites based on nanocrystalline polysaccharides. He also spent two years as postdoctoral fellow at the French Institute for Agricultural Research, INRA, where he developed new nanostructured thin films based on cellulose nanowiskers. Dr. Habibi’s research interests include the sustainable production of materials from biomass, development of high performance nanocomposites from lignocellulosic materials, biomass conversion technologies, and the application of novel analytical tools in biomass research. Chem. Rev. 2010, 110, 3479–3500 3479

Cellulose nanocrystals: chemistry, self-assembly, and applications.

Summary Background Since December, 2019, Wuhan, China, has experienced an outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epidemiological and clinical characteristics of patients with COVID-19 have been reported but risk factors for mortality and a detailed clinical course of illness, including viral shedding, have not been well described. Methods In this retrospective, multicentre cohort study, we included all adult inpatients (≥18 years old) with laboratory-confirmed COVID-19 from Jinyintan Hospital and Wuhan Pulmonary Hospital (Wuhan, China) who had been discharged or had died by Jan 31, 2020. Demographic, clinical, treatment, and laboratory data, including serial samples for viral RNA detection, were extracted from electronic medical records and compared between survivors and non-survivors. We used univariable and multivariable logistic regression methods to explore the risk factors associated with in-hospital death. Findings 191 patients (135 from Jinyintan Hospital and 56 from Wuhan Pulmonary Hospital) were included in this study, of whom 137 were discharged and 54 died in hospital. 91 (48%) patients had a comorbidity, with hypertension being the most common (58 [30%] patients), followed by diabetes (36 [19%] patients) and coronary heart disease (15 [8%] patients). Multivariable regression showed increasing odds of in-hospital death associated with older age (odds ratio 1·10, 95% CI 1·03–1·17, per year increase; p=0·0043), higher Sequential Organ Failure Assessment (SOFA) score (5·65, 2·61–12·23; p Interpretation The potential risk factors of older age, high SOFA score, and d-dimer greater than 1 μg/mL could help clinicians to identify patients with poor prognosis at an early stage. Prolonged viral shedding provides the rationale for a strategy of isolation of infected patients and optimal antiviral interventions in the future. Funding Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences; National Science Grant for Distinguished Young Scholars; National Key Research and Development Program of China; The Beijing Science and Technology Project; and Major Projects of National Science and Technology on New Drug Creation and Development.

Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study

A facile method for the fabrication of inorganic hollow materials from cuprammonium cellulose composite filaments based on fast pyrolysis has been developed. Unlike Ostwald ripening, approaches based on the Kirkendall effect, and other template methods, this process yielded hollow materials within 100 s. The heterogeneous structure of the cellulose composite fibers and the gradient distribution of the metal oxides are the main reasons for the formation of the hollow structure. The diameter, wall thickness, and length of the hollow microfibers could be conveniently controlled. With their perfect morphology, these hollow structural materials have great potential for use in various fields.

Fabrication of Hollow Materials by Fast Pyrolysis of Cellulose Composite Fibers with Heterogeneous Structures

A series of water-resistant cellulose films was prepared by coating castor oil based polyurethane (PU)/benzyl starch (BS) semi-interpenetrating polymer networks (semi-IPN). All of the coated films, with a very thin coating layer of about 0.4 μm, exhibited much better optical transmittance, water resistance, and mechanical properties than the original regenerated cellulose (RC) film, suggesting a strong interface interaction between PU/BS coating and cellulose substrate. The BS concentration in the coating had a significant effect on the properties of the coated films. With an increase of BS concentration in the coating from 10 to 70 wt %, the tensile strength and storage modulus of the coated films increased. Especially, as the tensile strength achieved a maximum value of 102 MPa, the elongation at break of the coated film still maintained a relatively higher value of 10%. Meanwhile, the coated films displayed good biodegradability, and the biodegradation rate increased with increasing BS concentration in...

Structure and properties of cellulose films coated with polyurethane/benzyl starch semi-IPN coating

Chemical structures of water-soluble polysaccharides from Rhizoma Panacis Japonici.

A series of 2,3-O-carboxymethylcelluloses (CMC's), which are regioselectively substituted at the C-2 and C-3 position, were prepared and their water solubility was examined. It was found that the lower limit for the degree of substitution (DS) value of water-soluble 2,3-O-CMC is about 0.3. This value was almost the same as that of CMC prepared in a slurry of isopropyl alcohol/water with isopropyl chloroacetate and sodium hydroxide, showing that the uniform alkylation is rather important to convert cellulose into water-soluble derivatives.

Lina Zhang

Papers

Fabrication of Hollow Materials by Fast Pyrolysis of Cellulose Composite Fibers with Heterogeneous Structures

Structure and properties of cellulose films coated with polyurethane/benzyl starch semi-IPN coating

Chemical structures of water-soluble polysaccharides from Rhizoma Panacis Japonici.

Water solubility of regioselectively 2,3-O-substituted carboxymethylcellulose

Solution properties of an α-(1→3)-d-glucan from Lentinus edodes and its sulfated derivatives