Review of nanocellulose for sustainable future materials Kim, Joo-Hyung; Shim, Bong Sup; Kim, Heung Soo ...
International journal of precision engineering and manufacturing-green technology,
04/2015, Volume:
2, Issue:
2
Journal Article
Open access
Cellulose, the chain of glucose residues easily obtained from nature, is the most common natural polymer. Owing to its own unique material properties, compared to the conventional usage, ...nanocellulose (NC) with a crystalline structure can be considered to be used in various industrial applications. As a novel sustainable future material, we review the recent achievements of NC from the view point of material extraction and the composite processes to some extended important applications. While the mechanical properties of NCs and the energy consumption during their composite processing are the key considerations, their application potentials have never been limited to mechanical or commodity products as conventional celluloses. In the latter part of this review, emerging engineering applications of NCs such as energy storage, flexible electronics, and smart materials will be further discussed for readers searching future high-end eco-friendly functional materials. Also some suggestions for potential applications will be also discussed.
► Cellulose/ionic liquid solution was successfully electrospun by addition of the co-solvent. ► As the weight ratio of the co-solvent increased, the finer and more uniform fiber-web was obtained. ► ...The co-solvent improved crystallinity and thermal stability.
The effects of the type and the concentration of the co-solvent on the spinnability during cellulose electrospinning and the properties of the fiber were studied using cellulose dissolved in ionic liquid and co-solvent (DMF or DMAc). The prepared solution was electrospun onto a wired collector and coagulated in ethanol. As the weight ratio of co-solvent against ionic liquid increased, the spinnability was improved with stable whipping and splaying motion. Regardless of the co-solvent type, the higher co-solvent concentration resulted in finer fiber diameter, better web uniformity, higher crystallinity and better thermal stability. Comparing to DMAc, DMF showed more significant influence on the fiber diameter and the crystallinity.
Peptides are promising therapeutic agents for COVID‐19 because of their specificity, easy synthesis, and ability to be fine‐tuned. We previously demonstrated that a cell‐permeable peptide ...corresponding to the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) Spike C‐terminal domain (CD) inhibits the interaction between viral spike and nucleocapsid proteins that results in SARS‐CoV‐2 replication in vitro. Here, we used docking studies to design R‐t‐Spike CD(D), a more potent short cell‐penetrating peptide composed of all D‐form amino acids and evaluated its inhibitory effect against the replication of SARS‐CoV‐2 S clade and other variants. R‐t‐Spike CD(D) was internalized into Vero cells and Calu‐3 cells and suppressed the replication of SARS‐CoV‐2 S clade, delta variant, and omicron variant with higher potency than the original peptide. In hemizygous K18‐hACE2 mice, intratracheal administration of R‐t‐Spike CD(D) effectively delivered the peptide to the trachea and lungs, whereas intranasal administration delivered the peptide mostly to the upper respiratory system and stomach, and a small amount to the lungs. Administration by either route reduced viral loads in mouse lungs and turbinates. Furthermore, intranasally administered R‐t‐Spike CD(D) mitigated pathological change in the lungs and increased the survival of mice after infection with the SARS‐CoV‐2 S clade or delta variant. Our data suggest that R‐t‐Spike CD(D) has potential as a therapeutic agent against SARS‐CoV‐2 infection.
Increased serum levels of immunoglobulin E (IgE) is a risk factor for various diseases, including allergy and anaphylaxis. However, the source and ontogeny of B cells producing IgE under steady state ...conditions are not well defined. Here, we show plasma cells that develop in the thymus and potently secrete IgE and other immunoglobulins, including IgM, IgA, and IgG. The development of these IgE-secreting plasma cells are induced by IL-4 produced by invariant Natural Killer T cells, independent of CD1d-mediated interaction. Single-cell transcriptomics suggest the developmental landscape of thymic B cells, and the thymus supports development of transitional, mature, and memory B cells in addition to plasma cells. Furthermore, thymic plasma cells produce polyclonal antibodies without somatic hypermutation, indicating they develop via the extra-follicular pathway. Physiologically, thymic-derived IgEs increase the number of mast cells in the gut and skin, which correlates with the severity of anaphylaxis. Collectively, we define the ontogeny of thymic plasma cells and show that steady state thymus-derived IgEs regulate mast cell homeostasis, opening up new avenues for studying the genetic causes of allergic disorders.
To investigate the molecular characteristics of human respiratory syncytial virus (HRSV) detected in Gyeonggi Province from 2015/16 to 2017/18, 2331 specimens from patients with sporadic acute ...respiratory illness and 85 specimens from four HRSV outbreaks in the postpartum care center were analyzed by real‐time reverse transcription PCR. HRSVs were detected in 97 of the 2416 (4.0%) specimens, and among the positive specimens, 38 (39.2%) were identified as HRSV‐A and 59 (60.8%) as HRSV‐B. During the study periods, HRSV‐B predominated in all seasons, except in 2016/17 during which HRSV‐A predominated. Depending on the age groups, HRSV prevalence was the highest in 0‐ to 2‐year‐old patients. Comparison of noninfected subjects with HRSV‐infected subjects revealed that HRSV infection more frequently resulted in fever, nasal obstruction, and wheezing, although the frequency of sore throat was low; however, comparison of the symptoms between HRSV‐A‐ and HRSV‐B‐infected patients revealed no significant differences in symptoms. Phylogenetic analysis showed that all HRSV‐A patients had an ON1 genotype, and all HRSV‐B patients had an BA9 genotype. These results provide a valuable reference regarding the circulating pattern and molecular characterization of HRSV. Continuous monitoring will be essential to detect newly emerging HRSV genotypes.
Highlights
HRSV‐B with BA9 genotype was predominant in South Korea from 2015 to 2018.
Heat shock proteins (HSPs) constitute a large family of molecular chaperones classified by their molecular weights, and they include HSP27, HSP40, HSP60, HSP70, and HSP90. HSPs function in diverse ...physiological and protective processes to assist in maintaining cellular homeostasis. In particular, HSPs participate in protein folding and maturation processes under diverse stressors such as heat shock, hypoxia, and degradation. Notably, HSPs also play essential roles across cancers as they are implicated in a variety of cancer-related activities such as cell proliferation, metastasis, and anti-cancer drug resistance. In this review, we comprehensively discuss the functions of HSPs in association with cancer initiation, progression, and metastasis and anti-cancer therapy resistance. Moreover, the potential utilization of HSPs to enhance the effects of chemo-, radio-, and immunotherapy is explored. Taken together, HSPs have multiple clinical usages as biomarkers for cancer diagnosis and prognosis as well as the potential therapeutic targets for anti-cancer treatment.
BACKGROUND:Air pollution may be related to adverse birth outcomes. Exposure information from land-based monitoring stations often suffers from limited spatial coverage. Satellite data offer an ...alternative data source for exposure assessment.
METHODS:We used birth certificate data for births in Connecticut and Massachusetts, United States (2000–2006). Gestational exposure to PM2.5 was estimated from US Environmental Protection Agency monitoring data and from satellite data. Satellite data were processed and modeled by using two methods—denoted satellite (1) and satellite (2)—before exposure assessment. Regression models related PM2.5 exposure to birth outcomes while controlling for several confounders. Birth outcomes were mean birth weight at term birth, low birth weight at term (<2500 g), small for gestational age (SGA, <10th percentile for gestational age and sex), and preterm birth (<37 weeks).
RESULTS:Overall, the exposure assessment method modified the magnitude of the effect estimates of PM2.5 on birth outcomes. Change in birth weight per interquartile range (2.41 μg/m) increase in PM2.5 was −6 g (95% confidence interval = −8 to −5), −16 g (−21 to −11), and −19 g (−23 to −15), using the monitor, satellite (1), and satellite (2) methods, respectively. Adjusted odds ratios, based on the same three exposure methods, for term low birth weight were 1.01 (0.98–1.04), 1.06 (0.97–1.16), and 1.08 (1.01–1.16); for SGA, 1.03 (1.01–1.04), 1.06 (1.03–1.10), and 1.08 (1.04–1.11); and for preterm birth, 1.00 (0.99–1.02), 0.98 (0.94–1.03), and 0.99 (0.95–1.03).
CONCLUSIONS:Under exposure assessment methods, we found associations between PM2.5 exposure and adverse birth outcomes particularly for birth weight among term births and for SGA. These results add to the growing concerns that air pollution adversely affects infant health and suggest that analysis of health consequences based on satellite-based exposure assessment can provide additional useful information.
Land use regression (LUR) models provide good estimates of spatially resolved long-term exposures, but are poor at capturing short term exposures. Satellite-derived Aerosol Optical Depth (AOD) ...measurements have the potential to provide spatio-temporally resolved predictions of both long and short term exposures, but previous studies have generally showed relatively low predictive power. Our objective was to extend our previous work on day-specific calibrations of AOD data using ground PM₂.₅ measurements by incorporating commonly used LUR variables and meteorological variables, thus benefiting from both the spatial resolution from the LUR models and the spatio-temporal resolution from the satellite models. Later we use spatial smoothing to predict PM₂.₅ concentrations for day/locations with missing AOD measures. We used mixed models with random slopes for day to calibrate AOD data for 2000–2008 across New-England with monitored PM₂.₅ measurements. We then used a generalized additive mixed model with spatial smoothing to estimate PM₂.₅ in location–day pairs with missing AOD, using regional measured PM₂.₅, AOD values in neighboring cells, and land use. Finally, local (100 m) land use terms were used to model the difference between grid cell prediction and monitored value to capture very local traffic particles. Out-of-sample ten-fold cross-validation was used to quantify the accuracy of our predictions. For days with available AOD data we found high out-of-sample R² (mean out-of-sample R² = 0.830, year to year variation 0.725–0.904). For days without AOD values, our model performance was also excellent (mean out-of-sample R² = 0.810, year to year variation 0.692–0.887). Importantly, these R² are for daily, rather than monthly or yearly, values. Our model allows one to assess short term and long-term human exposures in order to investigate both the acute and chronic effects of ambient particles, respectively.
Organic semiconductors (OSCs) are highly susceptible to the formation of metastable polymorphs that are often transformed by external stimuli. However, thermally reversible transformations in OSCs ...with stability have not been achieved due to weak van der Waals forces, and poor phase homogeneity and crystallinity. Here, a polymorph of a single crystalline 2,7‐dioctyl1 benzothieno3,2‐b1benzothio‐phene rod on a low molecular weight poly(methyl methacrylate) (≈120k) that limits crystal coarsening during solvent vapor annealing is fabricated. Molecules in the polymorph lie down slightly toward the substrate compared to the equilibrium state, inducing an order of greater resistivity. During thermal cycling, the polymorph exhibits a reversible change in resistivity by 5.5 orders with hysteresis; this transition is stable toward bias and thermal cycling. Remarkably, varying cycling temperatures leads to diverse resistivities near room temperature, important for nonvolatile multivalue memories. These trends persist in the carrier mobility and on/off ratio of the polymorph field‐effect transistor. A combination of in situ grazing incident wide angle X‐ray scattering analyses, visualization for electronic and structural analysis simulations, and density functional theory calculations reveals that molecular tilt governs the charge transport characteristics; the polymorph transforms as molecules tilt, and thereby, only a homogeneous single‐crystalline phase appears at each temperature.
A polymorph of a single crystalline 2,7‐dioctyl1 benzothieno3,2‐b1benzothio‐phene rod, synthesized on a low molecular weight poly(methyl methacrylate) exhibits a reversible change in resistivity by 5.5 orders with hysteresis during thermal cycling. Varying cycling temperatures lead to diverse resistivities near room temperature, important for nonvolatile multivalue memories. The polymorph transforms as molecules tilt and thus, only a homogeneous single‐crystalline phase appears at each temperature.
A distinction between quantitative and qualitative data has been regarded as an inviolable separation for a long time, resulting in a significant restriction in setting research designs and methods. ...In this study, we propose a way to pull this stereotype down and to open more choices for upcoming studies: using Python with 10-K filings via the U.S. Securities and Exchange Commission's application programming interface, we show how to broaden the source of data available for research. In particular, we focus on management's discussion and analysis (MD&A) of 10-K filing. This part has not been fully incorporated due to considerable requirements for an access - substantial time and effort in case of hand collecting. The new perspective approach described in this paper provides significant implications for business practice as well as research in relation to the higher level of utilization of existing data than before.
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