Fabrication of all-cellulose nanocomposites from corn stalk.

BACKGROUND: There is a need to help farmers and industries develop value-added composite and nanocomposite materials from agricultural residuals. Cellulose nanofibers (CNFs) were made using a TEMPO oxidation method and celluloses were prepared by acid-base method and extracting method, which were all from corn stalk, an agricultural residual. The prepared celluloses were dissolved separately in dimethylacetamide/LiCl solvent and CNFs were added at 0.0%, 0.5%, 1.5% and 3.0% to form all-cellulose nanocomposites, and then cast into films. Morphology, structure and properties of the nanocomposite films were characterized using atomic force microscopy, field emission scanning electron microscopy, thermogravimetric analysis, X-ray diffraction and mechanical testing. RESULTS: The all-cellulose nanocomposite films with different cellulose matrices exhibited good optical transparency and layer structure. The all-cellulose nanocomposite films with cellulose prepared by the extracting method (Composite E) exhibited a higher crystallinity, better thermal stability and higher mechanical strength compared to the all-cellulose nanocomposite films with cellulose prepared by the acid-base method (Composite A). CONCLUSIONS: The crystal structure of the all-cellulose nanocomposite films indicated the coexistence of cellulose I and cellulose II. However, in contrast to Composite A, the diffraction intensity of cellulose I in Composite E was higher than that of cellulose II. This was another reason that the mechanical properties of Composite E were superior to those of Composite A. In addition, the mechanical properties of the all-cellulose nanocomposite films were significantly different when the addition of CNFs reached 3.0% by weight, as indicated by a multiple-range comparison. © 2020 Society of Chemical Industry.

Value-Added Utilization of Wheat Straw: From Cellulose and Cellulose Nanofiber to All-Cellulose Nanocomposite Film.

To accelerate the high value-added usage of agricultural residue, cellulose and cellulose nanofibers (CNFs) were extracted from wheat straw and then formed into all-cellulose nanocomposite films. The acid-alkali method (AM) and the extraction method (EM) were respectively adopted to prepare wheat straw cellulose (WSC), and the TEMPO oxidation method was used to extract CNFs. The nanocomposite films were fabricated by dissolving WSC and adding different CNF contents of 0.0, 0.5, 1.5, and 3.0%. There was a better miscibility for the all-cellulose nanocomposite film prepared by EM (Composite-E) compared to that for the all-cellulose nanocomposite film prepared by AM (Composite-A). Composite-E also showed a better optical transparency than Composite-A. The thermal stability of the two RWSCs presented contrary results when the CNFs were added, indicating a higher thermal stability for Composite-E than for Composite-A. This should have determined the properties of the films in which Cellulose I and Cellulose II coexisted for the all-cellulose nanocomposite films, and the forming mechanism of Cellulose II and crystallinity were determined by the cellulose-extracting method. X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) spectroscopy also showed that there was more Cellulose I in Composite-E than in Composite-A. The results are expected to enrich the data for deep processing of agricultural residues.

Childhood maltreatment, subjective social status, and health disparities in bereavement.

BACKGROUND: Spousal bereavement can lead to adverse health outcomes; however, not all widow(er)s experience the same degree of health problems. Thus, it is important to understand the contribution of disparities (e.g., childhood maltreatment and subjective social status) that may underlie adverse health outcomes that arise following bereavement. METHODS: We collected data from 130 spousally bereaved individuals at 3-time points (3 months post-loss, 4 months post-loss, and 6 months post-loss). Using mixed models, we assessed the interaction of childhood maltreatment, subjective social status, and time to predict changes in proinflammatory cytokine production, depressive symptoms, grief symptoms. RESULTS: We found a significant interaction between childhood maltreatment, subjective social status, and time predicting proinflammatory cytokine production (beta > -0.01, p = 0.048), depressive symptoms (beta = 0.008, p = .010), and grief symptoms (beta = 0.001 p = .001). CONCLUSION: This study highlights the role of disparities related to childhood maltreatment and subjective social status on adverse health outcomes following spousal bereavement.

Short-term and long-term psychological impact and quality of life of patients undergoing orthognathic surgery.

BACKGROUND: Orthognathic Surgery (OGS) is a surgery for patients with dento-facial deformity but not all patients are satisfied with its outcome. The purpose of this study is to find out the short-term and long-term psychological impact and quality-of-life of OGS. METHODS: 77 participants receiving OGS and 32 age and gender-matched controls were enrolled. The data of questionnaires were collected before OGS, one month and 9 months after OGS, including short form of the Derriford-Appearance-Scale (DAS-24), Big-Five-Inventory (BFI), Hospital-Anxiety-and-Depression-Scale (HADS), Pittsburgh-sleep-quality-index (PSQI), and 36-Item Short-Form-Health-Survey (SF-36). Variables were presented as mean ± standard deviation or frequency. Paired t-test, ANOVA and MANOVA were used to evaluate the pre-and post-surgery data. RESULTS: Short-term and long-term satisfaction of OGS was high. Before OGS, BFI showed the extraversion had significant difference between the male and female OGS subgroups. Several domains of DAS-24 were significantly different between the OGS and the control groups. Both groups had no significant difference in PSQI, HADS and SF-36, except sleep-efficiency. After OGS, many domains of DAS-24 were significantly improved and the improvement persisted to 9 months later. Sleep-latency, physical-function, role-limitations-due-to-physical-health and social-functioning exacerbated after OGS. Sleep-latency, physical-function, and social-functioning were improved 9 months after OGS, but sleep-efficiency and role-limitations-due-to-physical-health were still significantly worse than controls. CONCLUSION: People received OGS for unfavorable appearance and the surgery could decrease their distress of appearance and impact to their daily living. Through long-term assessment, we should pay attention to sleep problems and role-limitations-due-to-physical-health after OGS.

Immune and Epigenetic Pathways Linking Childhood Adversity and Health Across the Lifespan.

Childhood adversity is associated with a host of mental and physical health problems across the lifespan. Individuals who have experienced childhood adversity (e.g., child abuse and neglect, family conflict, poor parent/child relationships, low socioeconomic status or extreme poverty) are at a greater risk for morbidity and premature mortality than those not exposed to childhood adversity. Several mechanisms likely contribute to the relationship between childhood adversity and health across the lifespan (e.g., health behaviors, cardiovascular reactivity). In this paper, we review a large body of research within the field of psychoneuroimmunology, demonstrating the relationship between early life stress and alterations of the immune system. We first review the literature demonstrating that childhood adversity is associated with immune dysregulation across different indices, including proinflammatory cytokine production (and its impact on telomere length), illness and infection susceptibility, latent herpesvirus reactivation, and immune response to a tumor. We then summarize the growing literature on how childhood adversity may alter epigenetic processes. Finally, we propose future directions related to this work that have basic and applied implications.

Thermal and Physico-Mechanical Characterizations of Thromboresistant Polyurethane Films.

Hemocompatibility remains a challenge for injectable and/or implantable medical devices, and thromboresistant coatings appear to be one of the most attractive methods to down-regulate the unwanted enzymatic reactions that promote the formation of blood clots. Among all polymeric materials, polyurethanes (PUs) are a class of biomaterials with excellent biocompatibility and bioinertness that are suitable for the use of thromboresistant coatings. In this work, we investigated the thermal and physico-mechanical behaviors of ester-based and ether-based PU films for potential uses in thromboresistant coatings. Our results show that poly(ester urethane) and poly(ether urethane) films exhibited characteristic peaks corresponding to their molecular configurations. Thermal characterizations suggest a two-step decomposition process for the poly(ether urethane) films. Physico-mechanical characterizations show that the surfaces of the PU films were hydrophobic with minimal weight changes in physiological conditions over 14 days. All PU films exhibited high tensile strength and large elongation to failure, attributed to their semi-crystalline structure. Finally, the in vitro clotting assays confirmed their thromboresistance with approximately 1000-fold increase in contact time with human blood plasma as compared to the glass control. Our work correlates the structure-property relationships of PU films with their excellent thromboresistant ability.

Preparation, characterization and evaluation of cellulose nanocrystal/poly(lactic acid) in situ nanocomposite scaffolds for tissue engineering.

Cellulose nanocrystal (CNC)/poly(lactic acid) (PLA) in situ nanocomposite scaffolds were fabricated by in situ polymerization of lactic acid and CNC which was directly utilized as aqueous suspension, followed by a process of thermally induced phase separation. The CNC/PLA in situ nanocomposite porous scaffolds were characterized by mechanical test, protein adsorption, hemolysis test, in vitro degradation measurement, TEM, FTIR, SEM and WAXD. Compared to the PLA scaffold, the CNC/PLA in situ nanocomposite scaffolds showed a greatly increased compression modulus, an improved hemocompatibility and protein adsorption capacity. The inclusion of CNCs boosted the in vitro degradation of the in situ nanocomposite porous scaffolds and facilitated the deposition of Ca2+, CO32-, PO43- ions in simulated body fluid. Furthermore, cell cultures were carried out on the CNC/PLA in situ nanocomposite porous scaffolds. In comparison with the PLA scaffold, the in situ nanocomposite scaffolds improved cell attachment and enhanced cell proliferation, denoting low cytotoxicity and good cytocompatibility. It can therefore be concluded that such scaffolds with excellent mechanical property, biocompatibility, biomineralization capacity and bioactivity hold great potential for bone tissue engineering.

Physico- and bio-activities of nanoscale regenerated cellulose nonwoven immobilized with lysozyme.

Lysozyme-cellulose conjugates are of wide interest for food packaging, tissue scaffolding, wound healing, and antimicrobial applications. Here a recycled cotton-based source of regenerated cellulose in combination with carboxylated carbon nanotubes and graphene oxide was configured as nonwoven nanofibrous mats through electrospinning and utilized to immobilize lysozyme. Scanning electron microscopy, Fourier transform-infrared spectra, thermal-gravimetric analysis, tensile test, and antibacterial assessments were conducted to characterize and determine physical and bioactive properties of the nonwoven nanofibrous mats. The resulted cellulose-lysozyme conjugates were found to have robust bioactivity with no indication of cell cytotoxicity. The study confirmed that the carbon-nanoparticle-modified cellulose nonwoven mats revealed a high antimicrobial activity after immobilization of lysozyme.

Cell-secreted extracellular matrix, independent of cell source, promotes the osteogenic differentiation of human stromal vascular fraction.

Lipoaspirates contain a readily accessible heterogeneous cell source for use in bone regeneration collectively referred to as the stromal vascular fraction (SVF). However, the osteogenic potential of SVF is inferior to other progenitor cell populations, thereby requiring alternative strategies to potentiate its effective use in cell-based therapies of bone repair. Cell-secreted extracellular matrix (ECM) is a promising substrate to guide cell phenotype or for use in biomaterial design, yet the instructional capacity of ECMs produced by various cell types is unknown. To determine whether the bioactivity of cell-secreted ECM was dependent on cell source, we assessed the osteogenic response of human SVF on ECMs secreted by bone marrow-derived mesenchymal stem cells (MSCs), adipose stromal cells (ASCs), and human dermal fibroblasts (HDFs). Tissue culture plastic (TCP), type I collagen, and ECM induced expression of integrin subunits α2, α5, and ß1 in SVF, yet seeding efficiency was only improved on MSC-derived ECM. Regardless of ECM source, SVF deposited over 8- and 1.3-fold more calcium compared to TCP and collagen-coated controls, respectively. Flow cytometry confirmed that SVF cultured on ECM retained CD31 and CD34 positive cell populations better than TCP. After depleting accessory cells, ASCs deposited significantly less calcium compared to donor-matched SVF. This function was partially restored in the presence of MSC-derived ECM when donor-matched endothelial cells (ECs) were added in an ASC/EC co-culture, confirming a role for ECs in osteogenic differentiation. These findings support the use of cell-derived ECM as a means to promote cell retention and osteogenic differentiation of SVF.

Regenerated cellulose micro-nano fiber matrices for transdermal drug release.

In this work, biobased fibrous membranes with micro- and nano-fibers are fabricated for use as drug delivery carries because of their biocompatibility, eco-friendly approach, and potential for scale-up. The cellulose micro-/nano-fiber (CMF) matrices were prepared by electrospinning of pulp in an ionic liquid, 1-butyl-3-methylimidazolium chloride. A model drug, ibuprofen (IBU), was loaded on the CMF matrices by a simple immersing method. The amount of IBU loading was about 6% based on the weight of cellulose membrane. The IBU-loaded CMF matrices were characterized by Fourier-transform infrared spectroscopy, thermal gravimetric analysis, and scanning electron microscopy. The test of ibuprofen release was carried out in an acetate buffer solution of pH5.5 and examined by UV-Vis spectroscopy. Release profiles from the CMF matrices indicated that the drug release rate could be determined by a Fickian diffusion mechanism.

Biobased Nano Porous Active Carbon Fibers for High-Performance Supercapacitors.

Activated carbon fibers (ACFs) with different pore structure have been prepared from wood sawdust using the KOH activation method. A study was conducted to examine the influence of the activation parameters (temperature, alkali/carbon ratio, and time) on the morphology and structure of the as-prepared ACFs developed in the process of pore generation and evolution. Activation temperature was very essential for the formation of utramicropores (<0.6 nm), which greatly contributed to the electric double layer capacitance. The significance of metallic potassium vapor evolved when the temperature was above 800 °C, since the generation of 0.8- and 1.1 nm micropores cannot be ignored. When the the KOH/fiber ratio was increased and the activation time was prolonged, to some extent, the micropores were enlarged to small mesopores within 2-5 nm. The sample with the optimal condition exhibited the highest specific capacitance (225 F g(-1) at a current density of 0.5 A g(-1)). Its ability to retain capacitance corresponding to 10 A g(-1) and 6 M KOH was 85.3%, demonstrating a good rate capability. With 10 000 charge-discharge cycles at 3 A g(-1), the supercapacitor kept 94.2% capacity, showing outstanding electrochemical performance as promising electrode material.

Crystalline characteristics of cellulose fiber and film regenerated from ionic liquid solution.

Regenerated cellulose fiber, fiber extrudate, and film were produced from cellulose solution prepared with raw pulp and ionic liquid solvent 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). Spinning setting was based on a dry-jet and wet-spun approach including extrusion, coagulation, drawing, drying, and winding. Crystallization of the experimental fiber, fiber extrudate, and film was evaluated using a technique of wide angle X-ray diffraction (WAXD). Crystallinity index, crystallite size, and crystal orientation factor were calculated and compared among these samples. Influence of die shape, die dimension, and drawing speed on the regenerated cellulose crystallinity was discussed. The study indicated that the pulp cellulose was a Cellulose I type structure. The cellulose regeneration from the [BMIM]Cl solution completed a transformation from this intermediate phase to a final Cellulose II phase. The die shape and dimension and drawing speed were all important factors affecting the crystallinity of regenerated cellulose fiber and film.

Kinetics modeling of dynamic pyrolysis of bagasse fibers.

The thermal decomposition mechanism of raw and treated bagasse fibers was modeled with three parallel independent first-order reactions. The kinetic parameters and pseudo components which best fit the experimental dynamic pyrolysis rate of bagasse was determined by means of the Matlab program using the least-square method. The calculated rate of thermal decomposition for each bagasse sample was consistent with experimental pyrolysis rate very well. A method was adopted to calculate the contents of cellulose, hemicelluloses, and lignin for bagasse fiber based on the dynamic pyrolysis model. The calculated contents of the untreated bagasse fiber agreed very well with some reported values from the literature. The effect of treatment conditions on the bagasse fiber compositions was also studied. From the three-dimensional plot for each of the three components, it could be observed that bagasse fibers treated under the intermediate alkaline condition could achieve the higher content of cellulose.

Fungal colonization of a pneumonectomy stump.

A 59-year-old woman developed mild recurring hemoptysis once a week for several months after a fall with trauma to the chest. Sixteen years earlier she had undergone a right pneumonectomy at a hospital elsewhere for sequelae of pulmonary tuberculosis. Bronchoscopy, performed because of the recent hemoptysis, showed material in the pneumonectomy stump. The material had a gelatinous appearance, green color with a pale margin, and oblique striations. The material was removed by grasping with forceps and withdrawing the bronchoscope. Grocott methanamine silver stain was positive for septate, nonpigmented fungal organisms. Anatomic pathology microscopy also showed mucous, acute inflammatory cells, and necrotic tissue. Cytopathology of washings from the bronchial stump showed rare degenerated benign bronchial epithelial cells and fungal hyphae. Acid fast bacilli smears and cultures were negative. Bacterial cultures showed 3+ Pseudomonas aeruginosa. The patient had no further hemoptysis.