Rapid Benzylation of Cellulose in Tetra‑<i>n</i>‑butylphosphonium Hydroxide Aqueous Solution at Room Temperature

We found a very fast benzylation of cellulose in a tetraalkyl-onium hydroxide solvent system, 47% tetra-<i>n</i>-butylphosphonium hydroxide aqueous solution. Benzyl cellulose (BC) with a degree of substitution (DS) above 2.5 was obtained within 10 min at ambient temperature (20–25 °C) using ∼9 mol equiv of benzyl bromide to the anhydroglucose unit. The highly efficient benzylation proceeded in the transiently stabilized emulsion state of the reaction system, and the product precipitated out as a solid sediment in the liquid medium. At 20 °C, the benzyl DS was 1.92 after 2 min, and reached 2.40 and 2.53 after 5 and 10 min, respectively. The reaction temperature had a negative correlation with the maximum DS in the explored range of 10–50 °C. No significant degradation of the cellulosic main chain was observed for highly substituted BCs (DS > 2.5). The solubility of BC in common organic solvents was also examined for products with various DSs

Calcium Phosphate Mineralization in Cellulose Derivative/Poly(acrylic acid) Composites Having a Chiral Nematic Mesomorphic Structure

Calcium phosphate mineralization was conducted by using polymer composites of liquid-crystalline (ethyl)­cellulose (EC) or (hydroxypropyl)­cellulose (HPC) with poly­(acrylic acid) (PAA) as a scaffolding medium for the inorganic deposition. The EC/PAA and HPC/PAA samples were prepared in colored film form from EC and HPC lyotropic liquid crystals of left-handed and right-handed chiral nematics, respectively, by polymerization and cross-linking of acrylic acid as the main solvent component. The mineralization was allowed to proceed in a batchwise operation by soaking the liquid-crystalline films in an aqueous salt solution containing the relevant ions, Ca²⁺ and HPO₄^2–. The calcium phosphate-deposited EC/PAA and HPC/PAA composites (weight gain, typically 15–25% and 6–11%, respectively) retained the chiral nematic organization of the respective original handedness but exhibited selective light-reflection of longer wavelengths relative to that of the corresponding nonmineralized samples. From X-ray diffraction and energy-dispersive X-ray spectroscopy measurements, it was deduced that the calcium and phosphorus were incorporated inside the polymer matrices in three forms: amorphous calcium phosphate, hydroxyapatite, and a certain complex of PAA-Ca²⁺. Dynamic mechanical analysis and thermogravimetry revealed that the inorganic hybridization remarkably enhanced the thermal and mechanical performance of the optically functionalized cellulosic/synthetic polymer composites; however, the effect was more drastic in the EC/PAA series rather than the HPC/PAA series, reflecting the difference in the deposited mineral amount between the two

Synthesis of Novel Fluorescent Cellulose Derivatives and Their Applications in Detection of Nitroaromatic Compounds

A series of fluorescent cellulose derivatives (AC-AET-DMANMs) with different degrees of substitution (DS) were successfully prepared. First, allyl cellulose (AC) was synthesized from cellulose in NaOH/urea aqueous solution, and then 2-aminoethanethiol (AET) was introduced onto the cellulose backbone via a thiol–ene click reaction. Finally, the fluorescent groups were introduced by the reaction of the AET-modified AC with 4-dimethylamine-1,8-naphthalic anhydride (DMANA). The structure and fluorescent properties of AC-AET-DMANMs were characterized by elemental analysis and FT-IR, ¹H NMR, UV–vis, and fluorescence spectroscopy. AC-AET-DMANM with lower DS_DMANM (referring to the DS of naphthalimide groups, ≤0.25) was soluble in DMSO. AC-AET-DMANM of DS_DMANM ≤ 0.09 displayed stable fluorescence in DMSO and even in the solid state. The emission of AC-AET-DMANM in DMSO quantitatively and sensitively responded to 2,4,6-trinitrophenol (TNP) and 2,4-dinitrophenylhydrazine (DNH) by fluorescence quenching, and the limits of detection were determined to be 1.4 × 10^–7 and 9.9 × 10^–8 mol/L, respectively. Moreover, a water-soluble fluorescent derivative (AC-AET-DMANM-2W) was prepared by a further thiol–ene click reaction between AC-AET-DMANM-2 and AET. It can also be applied in the detection of TNP and DNH in aqueous media with the detection limits of 2.5 × 10^–8 and 3.2 × 10^–8 mol/L, respectively. The quenching mechanism is attributed to the photoinduced electron transfer and resonance energy transfer of the fluorescent cellulose derivatives to TNP/DNH molecules. The results illustrate a high applicability of the novel fluorescent cellulose derivatives to the detection of specific chemical entities in aqueous/nonaqueous media

Schematic illustrations of the psychophysical tasks.

<p>In both the Global and Local tasks, compound letter stimuli appeared after a 2-second presentation of a visual cue that indicated whether the target was a global or local letter. The subjects were instructed to respond orally to the target component of each compound letter stimulus as quickly as possible. In these tasks, the subjects maintained their attention on a single component of the compound letters (either the local or global component of the stimuli), and they were not required to reorient their attention. However, in the Mixed task, the cue that indicated the target component of the compound letter changed from trial to trial in a pseudorandom manner. The task required that the subjects switch their attention on the basis of the cue that was presented to them on each trial.</p

Results of the whole-brain voxel-based analyses.

<p>First row: The brain regions that exhibited regional cerebral glucose metabolic reductions in the 60 PD patients relative to 14 normal volunteers (p<0.05 uncorrected, extent threshold of 100 voxels). Second row and below: The brain regions in which the resting CMRglc was correlated with the RTs in the various psychophysical tasks (Global: second row, Local: third row, Mixed: fourth row) and the shift cost (fifth row) (<i>p</i><0.001 uncorrected, extent threshold of 100 voxels). PD, Parkinson’s disease; R, right; L, left.</p

The results of the ROI-based stepwise multiple regression analyses.

<p>7 ROIs are shown in different colors: right DLPFC  =  red, left DLPFC  =  cyan, left VLPFC  =  yellow, right TPO  =  purple, left TPO  =  green, medial parietal cortex  =  white, and left posterior IT  =  blue. The scatterplots illustrate the relationship between the psychophysical task performance scores and the FDG-uptake values in the ROIs. DLPFC, dorsolateral prefrontal cortex; VLPFC, ventrolateral prefrontal cortex; TPO, temporo-parieto-occipital junction; posterior IT, posterior inferior temporal cortex; FDG, ¹⁸F-fluorodeoxyglucose.</p

Effects of the mood induction procedure on mood and pareidolic illusions.

<p>(A) In both the DLB and AD groups, the sSTAI scores were highest under the negative mood condition and lowest under the positive mood condition, which indicates that the target moods were successfully induced by the experimental manipulations. DLB, dementia with Lewy body disease; AD, Alzheimer's disease; sSTAI, short form of the State-Trait Anxiety Inventory. (B) In the DLB group, the numbers of pareidolic responses were significantly larger under the negative mood condition (24.1 ± 20.5) than those under the neutral mood condition (11.2 ± 16.1) and were similar between the positive (9.4 ± 15.4) and neutral mood conditions. There were no significant differences in the number of pareidolic responses across the 3 mood conditions in the AD group.</p

Demographic and clinical characteristics of patients with PD and control participants.

<p>PD, Parkinson’s disease; MMSE, Mini Mental State Examination; CDR, Clinical Dementia Rating; NPI, Neuropsychiatric Inventory; UPDRS-III, Unified Parkinson’s Disease Rating Scale-motor score; L, left; R, right; B, bilateral.</p

Results of the multiple linear regression analysis.

<p>Results of the multiple linear regression analysis.</p

Signal detection theory analysis of the pareidolia test for DLB patients.

<p>(Left) No significant differences were observed across the 3 mood conditions in <i>d</i>_<i>e</i><i>'</i> (discrimination ability). (Right) <i>Ce</i> (criterion/bias) was significantly modulated by the induced mood and was highest under the negative mood condition and lowest under the positive mood condition. DLB, dementia with Lewy body disease.</p