Efficient cellulose dissolution and derivatization enabled by oxalic/sulfuric acid for high-performance cellulose films as food packaging.

The performance of cellulose-based materials is highly dependent on the choice of solvent systems. Exceptionally, cellulose dissolution and derivatization by efficient solvent have been considered as a key factor for large-scale industrial applications of cellulose. However, cellulose dissolution and derivatization often requires harsh reaction conditions, high energy consumption, and complex solubilizing, resulting in environmental impacts and low practical value. Here we address these limitations by using a low-temperature oxalic acid/sulfuric acid solvent to enable cellulose dissolution and derivatization for high-performance cellulose films. The dissolution and derivatization mechanism of the mixed acid is studied, demonstrating that cellulose is firstly socked by oxalic acid, then more hydrogen bonds ionized by sulfuric acid break cellulose chain, and finally the esterification reaction between oxalic acid and cellulose is catalyzed by sulfuric acid. Solutions containing 8 %-10 % cellulose are obtained and can be stored for a long time at -18 °C without significant degradation. Moreover, the cellulose film exhibits a higher tensile strength of up to 66.1 MPa, thermal stability, and degree of polymerization compared to that fabricated by sulfuric acid. These unique advantages provide new paths to utilize renewable resources for alternative food packaging materials at an industrial scale.

Tailoring Hydronium ion Driven Dissociation-Chemical Cross-Linking for Superfast One-Pot Cellulose Dissolution and Derivatization to Build Robust Cellulose Films.

Concepts of sustainability must be developed to overcome the increasing environmental hazards caused by fossil resources. Cellulose derivatives with excellent properties are promising biobased alternatives for petroleum-derived materials. However, a one-pot route to achieve cellulose dissolution and derivatization is very challenging, requiring harsh conditions, high energy consumption, and complex solubilizing. Herein, we design a one-pot tailoring hydronium ion driven dissociation-chemical cross-linking strategy to achieve superfast cellulose dissolution and derivatization for orderly robust cellulose films. In this strategy, there is a powerful driving force from organic acid with a pKa below 3.75 to dissociate H+ and trigger the dissolution and derivatization of cellulose under the addition of H2SO4. Nevertheless, the driving force can only trigger a partial swelling of cellulose but without dissolution when the pKa of organic acid is above 4.26 for the dissociation of H+ is inhibited by the addition of inorganic acid. The cellulose film has high transmittance (up to ∼90%), excellent tensile strength (∼122 MPa), and is superior to commercial PE film. Moreover, the tensile strength is increased by 400% compared to cellulose film prepared by the ZnCl2 solvent. This work provides an efficient solvent, which is of great significance for emerging cellulose materials from renewable materials.

"Green" electrostatic droplet-assisted forming cellulose microspheres with excellent structural controllability and stability for efficient Cr(VI) removal.

This study presents a novel and environmentally friendly method for producing cellulose microspheres (CM) with controllable morphology and size using electrostatic droplets. The traditional droplet method for CM production requires complex equipment and harmful reagents. In contrast, the proposed method offers a simple electrostatic droplet approach to fabricate CM10 at 10 kV, which exhibited a smaller volume, linear microscopic morphology, and a larger specific surface area, with a 36.60 % improvement compared to CM0 (prepared at 0 kV). CM10 also demonstrated excellent underwater structural stability, recovering in just 0.5 s, and exhibited the highest adsorption capacity for Cr(VI) at 190.16 mg/g, a 72.15 % improvement over CM0. This enhanced adsorption capacity can be attributed to the unique structure of CM10 and the introduction of more amino groups. Moreover, CM10 displayed good cyclic adsorption capacity and high dynamic adsorption efficiency, making it highly suitable for practical applications. CM10 exhibited remarkable adsorption capacity, stability, and practical value in treating Cr(VI) wastewater. This work proposes a simple and eco-friendly method for producing CM with excellent structural controllability and stability, providing an effective route for wastewater treatment.

Next-generation self-adhesive dressings: Highly stretchable, antibacterial, and UV-shielding properties enabled by tannic acid-coated cellulose nanocrystals.

Hydrogels with excellent high-water uptake and flexibility have great potential for wound dressing. However, pure hydrogels without fiber skeleton faced poor water retention, weak fatigue resistance, and mechanical strength to hinder the development of the dressing as next-generation functional dressings. We prepared an ultrafast gelation (6 s) Fe3+/TA-CNC hydrogel (CTFG hydrogel) based on a self-catalytic system and bilayer self-assembled composites. The CTFG hydrogel has excellent flexibility (800% of strain), fatigue resistance (support 60% compression cycles), antibacterial, and self-adhesive properties (no residue or allergy after peeling off the skin). CTFG@S bilayer composites were formed after electrospun silk fibroin (SF) membranes were prepared and adhesive with CTFG hydrogels. The CTFG@S bilayer composites had significant UV-shielding (99.95%), tensile strain (210.9 KPa), and sensitive humidity-sensing properties. Moreover, the integrated structure improved the mechanical properties of electrospun SF membranes. This study would provide a promising strategy for rapidly preparing multifunctional hydrogels for wound dressing.

Highly efficient dissolution and reinforcement mechanism of robust and transparent cellulose films for smart packaging.

The packaging of fresh foods increasingly focuses on renewable and eco-friendly cellulose films, but their low dissolution efficiency and weak mechanical strength greatly limit their wide application, which also cannot be used for smart packaging. Here, a highly efficient synergistic chloride-salt dissolution method was proposed to fabricate robust, transparent, and smart cellulose films. Cellulose films with appropriate Ca2+ concentration exhibited robust mechanical strength, better thermal stability, high transparency and crystallinity. The metal chelation of Ca2+ with cellulose chains could induce cellulose chain arrangement during the cellulose regeneration process. Particularly, compared to pure cellulose films, the tensile strength and elongation at break of cellulose films with suitable Ca2+ were increased by 167 % and 200 %, respectively. Moreover, optimal cellulose films can be used to reflect the quality of the fruit by detecting changes in ethanol gas. Hence, a novel strategy is presented to fabricate robust and transparent cellulose films with great potential application for smart packaging.

Deep insights into biodegradability mechanism and growth cycle adaptability of polylactic acid/hyperbranched cellulose nanocrystal composite mulch.

The widespread use of petroleum-based plastic mulch in agriculture has accelerated white and microplastic pollution while posing a severe agroecological challenge due to its difficulty in decomposing in the natural environment. However, endowing mulch film with degradability and growth cycle adaptation remains elusive due to the inherent non-degradability of petroleum-based plastics severely hindering its applications. This work reports polylactic acids hyperbranched composite mulch (PCP) and measured biodegradation behavior under burial soil, seawater, and ultraviolet (UV) aging to understand the biodegradation kinetics and to increase their sustainability in the agriculture field. Due to high interfacial interactions between polymer and nanofiler, the resultant PCP mulch significantly enhances crystallization ability, hydrophilicity, and mechanical properties. PCP mulch can be scalable-manufactured to exhibit modulated degradation performance under varying degradation conditions and periods while concurrently enhancing crop growth (wheat). Thus, such mulch with excellent performance can reduce labor costs and the environmental impact of waste mulch disposal to replace traditional mulch for sustainable agricultural production.

Multiple noncovalent interactions tailored crystallization and performance reinforcement mechanisms of Biopolyester Composites with functional Cellulose Nanocrystals.

The slow crystallization and weak mechanical features of poly (butylene adipate-co-terephthalate) (PBAT) have become a severe industrial problem in food packaging. Inspired by principle of bionic structure, functional cellulose nanocrystals (CNC) modified with hexamethylene diisocyanate (HMDI) and toluene diisocyanate (TDI) can enhance the crystallization ability and mechanical properties of PBAT nanocomposites. Significantly, CNC-T (CNC modified by TDI) showed a stronger reinforced effect on PBAT properties than unmodified CNCs and CNC-H (CNC modified by HMDI) nanofillers due to hydrogen bonds, π-π interaction between PBAT matrix and CNC-T nanofillers with benzene ring structure. Thus, compared with pure PBAT, PBAT/5CNC-T composites displayed an enhancement of 34.5 % on the tensile strength and exhibited the most robust nucleation ability on PBAT crystallization than CNC and CNC-H. Meanwhile, the possible nucleation, crystallization, and performance reinforcement mechanisms of PBAT nanocomposites have been presented, which is very beneficial for designing robust PBAT nanocomposites with functional cellulose nanocrystals for potential green packaging.

Research on the Role of Innovative Interactive Medical Humanities Education in Standardized Training for Pediatric Residents / 中国医学伦理学

The cultivation of medical humanistic quality is indispensable in the standardized training of pediatric residents, and it is urgent to explore new educational methods to improve their medical humanistic quality level. In this study, 60 standardized pediatricians participated in the standardized training, 36 in the experimental group received innovative interactive medical humanities education, while 24 in the control group were set up to receive traditional medical humanities education. Short-term and long-term test scores were conducted by questionnaire at the beginning of the standardized training and 2 years later. The results showed that there was no significant difference between the experimental group and the control group in the self-scores of professional quality, moral cultivation, communication skills, legal knowledge and innovative spirit (P>0.05) , but the scores of teaching teachers were improved except innovative spirit (P<0.05) . In addition, compared with the control group, the number of pediatricians with professional honor increased, the doctor-patient communication ability improved, the medical disputes reduced, and the family satisfaction improved in experimental group were increased (P<0.05) . These results indicated that innovative interactive medical humanistic education is an effective method to improve the medical humanistic quality of pediatric residents in standardized training.

Robust and versatile superhydrophobic cellulose-based composite film with superior UV shielding and heat-barrier performances for sustainable packaging.

Replacing single-use plastic delivery bags (SPDBs) with cellulose-based materials is an effective strategy to reduce environmental pollution. However, the inherent hydrophilicity and ultralow mechanical strength of cellulose materials limit its development. In this study, zinc oxide (ZnO)-cellulose composite films were successfully prepared through "two-step strategy" of lotus leaves structure simulation, including deposition of micro-nano ZnO particles and stearic acid (STA) modification. Well-dispersed micro-nano ZnO particles with stick-like structure were anchored in the ZnO-cellulose composite film prepared at 90 °C (CF-90). Due to the special structural design and strong interaction between the cellulose and micro-nano ZnO particles, the CF-90 showed higher mechanical property (a 47.8 % improvement in the tensile strength). Impressively, CF-90 also exhibited great UV shielding properties with larger UPF value of 1603.98 and superhigh heat-barrier performance. Moreover, CF-90 obtained excellent superhydrophobicity with a water contact angle of 163.6° by further modification. Consequently, the versatile cellulose-based material bringing a dawn on application of sustainable packaging materials for express delivery industry.

Multi-functional nanocellulose based nanocomposites for biodegradable food packaging: Hybridization, fabrication, key properties and application.

Nowadays, non-degradable plastic packaging materials have caused serious environmental pollution, posing a threat to human health and development. Renewable eco-friendly nanocellulose hybrid (NCs-hybrid) composites as an ideal alternative to petroleum-based plastic food packaging have been extensively reported in recent years. NCs-hybrids include metal, metal oxides, organic frameworks (MOFs), plants, and active compounds. However, no review systematically summarizes the preparation, processing, and multi-functional applications of NCs-hybrid composites. In this review, the design and hybridization of various NCs-hybrids, the processing of multi-scale nanocomposites, and their key properties in food packaging applications were systematically explored for the first time. Moreover, the synergistic effects of various NCs-hybrids on several properties of composites, including mechanical, thermal, UV shielding, waterproofing, barrier, antimicrobial, antioxidant, biodegradation and sensing were reviewed in detailed. Then, the problems and advances in research on renewable NCs-hybrid composites are suggested for biodegradable food packaging applications. Finally, a future packaging material is proposed by using NCs-hybrids as nanofillers and endowing them with various properties, which are denoted as "PACKAGE" and characterized by "Property, Application, Cellulose, Keen, Antipollution, Green, Easy."

Homogeneous wet-spinning construction of skin-core structured PANI/cellulose conductive fibers for gas sensing and e-textile applications.

Fiber-based wearable electronic textiles have broad applications, but non-degradable substrates may contribute to electronic waste. The application of cellulose-based composite fibers as e-textiles is hindered by the lack of fast and effective preparation methods. Here, we fabricated polyaniline (PANI)/cellulose fibers (PC) with a unique skin-core structure through a wet-spinning homogeneous blended system. The conductive network formation was enabled at a mere 1 wt% PANI. Notably, PC15 (15 wt% PANI) shows higher electrical conductivity of 21.50 mS cm-1. Further, PC15 exhibits excellent ammonia sensing performance with a sensitivity of 2.49 %/ppm and a low limit of detection (LOD) of 0.6 ppm. Cellulose-based composite fibers in this work demonstrate good gas sensing and anti-static properties as potential devices for smart e-textiles.

All-naturally structured tough, ultrathin, and washable dual-use composite for fruits preservation with high biosafety evaluation.

This work develops a sustainable and global strategy to enhance fruit preservation efficacy. The dual-use composite coating or film comprises silk fibroin/cellulose nanocrystals (SF/CNC) with superior ductility through a synergistic plasticizing effect of glycerol and natural aloe-emodin powder (AE) as antimicrobial agents. To confirm our strategy, two common fruit preservation materials (edible surface coating-SCA-CS; packaging film-SCA-PF) and five different fruits (strawberries, bananas, apples, blueberries, and guavas) have been used. Moreover, SCA-CS coating with antibacterial and antioxidant activities formed an ultrathin layer on the fruit's surfaces with a thickness of 7.7 µm and could be easily washable. Therefore, bananas and strawberries' shelf-life with SCA-CS coating can be extended for 9 days and 6 days, respectively. The discharge water of SCA-CS has excellent biosafety in an indoor environment with no threat to plant health (microgreens bean sprouts germination as a case study). The plant exhibited positive results within 15 days, and leaves maintained their green color with a germination rate of 97.6 %. The toughness of SCA-PF film increased by 14,685.7 % with a water vapor transmission rate (WPTR) of 17 g mm m-2 day-1, which confirms that the concept of SCA-PF film and SCA-CS coating are feasible to be used for fruit preservation/packaging.

One-pot strategy to fabricate conductive cellulose nanocrystal-polyethylenedioxythiophene nanocomposite: Synthesis mechanism, modulated morphologies and sensor assembly.

Simple preparation, good conductivity, and excellent hydrophilicity are in urgent demand due to fast growth of wearable intelligent devices. Cellulose nanocrystal-polyethylenedioxythiophene (CNC-PEDOT) nanocomposites with modulated morphology were prepared through Iron (III) p-toluenesulfonate hydrolysis of commercialized microcrystalline cellulose (MCC) and in situ polymerization of 3,4-ethylenedioxythiophene monomers (EDOT) through one-pot green synthesis, where preparation and modification of CNC were obtained for uses as templates to anchor PEDOT nanoparticles. The resultant CNC-PEDOT nanocomposite gave well-dispersed PEDOT nanoparticles with sheet-like structure on the CNC surface, possessing higher conductivity and improved hydrophilicity or dispersibility. Subsequently, a wearable non-woven fabrics (NWF) sensor was successfully assembled by dipping the conductive CNC-PEDOT, and showed excellent sensing response for multiple signals (subtle deformation from various human activities and temperature). This study provides a feasible and large-scale production of CNC-PEDOT nanocomposites and their applications in wearable flexible sensors and electronic devices.

Thermo-sensitive composite microspheres incorporating cellulose nanocrystals for regulated drug release kinetics.

Thermo-sensitive composite microspheres (TPCP) were developed to achieve the on-demand release of drugs. The TPCP microspheres were synthesized using Oil-in-Water (O/W) emulsion evaporation technique and then impregnated with thermo-sensitive polyethylene glycol (PEG). The addition of cellulose nanocrystals (CNCs) significantly enhance thermal stability, crystallization ability, and surface hydrophilicity of TPCP microspheres due to heterogeneous nucleation effect and hydrogen bonding interaction, resulting in stable microsphere structure. The thermal degradation temperature (Tmax) increased by 13.8 °C, and the crystallinity improved by 20.9 % for 10 % TPCP. The thermo-sensitive composite microspheres showed the regulated cumulative release according to in vitro human physiological temperature changes. Besides, four release kinetics and possible release mechanism of TPCP microspheres were provided. Such thermo-responsive composite microspheres with control microsphere sizes and high encapsulation rate may have the potential to the development of on-demand and advanced controlled-release delivery systems.

Analysis of the efficiency and influencing factors of peripheral blood hematopoietic stem cell collection / 中国医师进修杂志

Objective:To investigate the collection efficiency of peripheral blood hematopoietic stem cells and explore its influencing factors.Method:The parameters of the collection process, blood routine indexes and the number of MNC and CD 34+ cells of the product were detected by Fresenius blood cell separator, Mindray blood cell analyzer and BD flow cytometer. A retrospective analysis was performed on 72 patients who underwent autologous peripheral blood hematopoietic stem cell transplantation in Southwest Hospital of Army Medical University from January 2013 to January 2021, including the correlation among gender, age, blood routine indexes, collection circulation volume and MNC and CD 34+ cell count in these cases, and influence of various factors on collection efficiency of peripheral blood stem cells. The correlation among gender, age, blood routine indexes, collection circulation volume and MNC and CD 34+ cell count in 72 cases of autologous transplantation patients, and influence of various factors on collection efficiency of peripheral blood stem cells were analyzed retrospectively. Results:There were no significant differences in collecting efficiency of peripheral blood stem cells among patients with different age, sex and disease type ( P>0.05). The collected MNC count of all patients was positively correlated with the collection cycle count ( r = 0.33, P<0.001) and WBC count after mobilization ( r = 0.41, P<0.001). The number of CD 34+ cells collected was positively correlated with MNC count after mobilization ( r = 0.38, P<0.001) and the amount of white membrane collected ( r = 0.48, P<0.001). Logistic multivariate regression analysis showed that MNC count after mobilization: P<0.001, 95% CI 0.07(0.05 - 0.09), collection cycle amount [ P<0.001, 95% CI 0.00(0.00 - 0.00)] and postharvest total amount [ P<0.001, 95% CI 0.07(0.05 - 0.10)] were the influencing factors of the collected MNC number. Meanwhile, these factorswere also the influencing factors of the collected CD 34+ number (MNC count after mobilization: P<0.001, 95% CI 0.09(0.04 - 0.14); collection cycle amount: P = 0.003, 95% CI 0.00(0.00 - 0.00); postharvest total amount: P = 0.005, 95% CI 0.08(0.03 - 0.14)). Conclusions:The collection efficiency of peripheral blood stem cells varies greatly among individuals. The more MNC counts after mobilization, the more peripheral blood stem cells could be collected. In order to obtain high collection efficiency, it is necessary to adjust the parameters of peripheral blood MNC before collection, and pay attention to the collection circulation quantity, postharvest total amount and white membrane volume.

Electroconductive cellulose nanocrystals - Synthesis, properties and applications: A review.

There is a growing interest in the synthesis of electrically conductive cellulose nanocrystal (CNC) for advanced applications, such as supercapacitor, batteries, sensor, and printed electronics. CNC is recognized as an attractive template for the fabrication of functional nanomaterials. Since CNC possesses many attractive properties, it is a sustainable template to prepare conductive nanomaterials, by either coating it with a conductive material or transforming it into carbon nanorods. This review summarizes the utilization of a sustainable and low-cost CNC to produce conductive nanocomposites via an environmentally friendly process. Electroconductive CNCs with enhanced electrical properties, lower electrical percolation threshold, and better mechanical properties can be produced and are attractive systems for many new applications.

Chain-ring covalently interconnected cellulose nanofiber/MWCNT aerogel for supercapacitors and sensors.

Bending multi-walled carbon nanotubes (MWCNTs) into rings and structuring them into aerogels is difficult. In this study, cellulose nanofiber (CNF)-MWCNT composite fibers with chain-ring structures were prepared by covalently interconnecting carboxylated CNF and aminated MWCNT by dehydration condensation, solving the problems of the formation of MWCNT aerogels and their phase separation during the compounding process and providing CNF-based aerogels with electrical conductivity. The covalently interconnected aerogels (CAs) had hierarchical porous structures with mechanical resilience and chain-ring fibers, which drove the CNF and MWCNT to form a continuous homogeneous network resulting in a high compression resistance of 269.02 kPa. The CA-based flexible all-solid-state supercapacitor had a quality specific capacitance of 114.8 F g-1, a capacitance retention rate of 94.78% and a Coulomb efficiency of 100%. The CA-based flexible sensor can sense different pressures with a stable response for 1000 cycles. This first study of pulling and bending MWCNT through CNF is expected to inspire more applications of MWCNTs in the fields of flexible supercapacitors and sensors.

Flexible, anti-damage, and non-contact sensing electronic skin implanted with MWCNT to block public pathogens contact infection.

If a person comes into contact with pathogens on public facilities, there is a threat of contact (skin/wound) infections. More urgently, there are also reports about COVID-19 coronavirus contact infection, which once again reminds that contact infection is a very easily overlooked disease exposure route. Herein, we propose an innovative implantation strategy to fabricate a multi-walled carbon nanotube/polyvinyl alcohol (MWCNT/PVA, MCP) interpenetrating interface to achieve flexibility, anti-damage, and non-contact sensing electronic skin (E-skin). Interestingly, the MCP E-skin had a fascinating non-contact sensing function, which can respond to the finger approaching 0-20 mm through the spatial weak field. This non-contact sensing can be applied urgently to human-machine interactions in public facilities to block pathogen. The scratches of the fruit knife did not damage the MCP E-skin, and can resist chemical corrosion after hydrophobic treatment. In addition, the MCP E-skin was developed to real-time monitor the respiratory and cough for exercise detection and disease diagnosis. Notably, the MCP E-skin has great potential for emergency applications in times of infectious disease pandemics. Electronic Supplementary Material: Supplementary material (fabrication of MCP E-skin, laser confocal tomography, parameter optimization, mechanical property characterization, finite element simulation, sensing mechanism, signal processing) is available in the online version of this article at 10.1007/s12274-021-3831-z.

Research advances of music therapy and its application in the field of burn treatment / 中华烧伤杂志

Different from other trauma, the scar and pigmentation formed after healing of burn wound not only hinder beauty but also easily lead to a series of sequential psychological problems, such as depression and anxiety. Music therapy, as a supplementary treatment, is widely used in many fields including medical and health care and psychological regulation. However, affected by factors such as medical resources, the awareness and acceptance of music therapy among burn treatment workers in China are still low. Based on the clinical characteristics of burns, this paper matches the applicability of music therapy with it, summarizes the supplementary application of music therapy in the field of burn treatment, expounds this natural science with both science and aesthetics, and puts forward feasible suggestions for its future development.

Effects of occupational mercury exposure on the immune function of workers / 中国职业医学

@#Objective To investigate the effects of mercury on T lymphocytes and serum immune indexes of workers with Methods occupational mercury exposure. A total of 45 workers with occupational mercury exposure were selected as the ， mercury exposure group and 47 workers without occupational mercury exposure were selected as the control group using the judgment sampling method. Cold atomic absorption spectrometry was used to detect the urinary mercury level of the two groups. （ ） +， + +， + + - + Flow cytometry was used to detect the proportion of cluster of differentiation CD 3 CD3CD4 CD3CD8 and CD3CD19 ， - （ - ） - （ - ） cells in peripheral blood and the levels of tumor necrosis factor α TNF α and interleukin 8 IL 8 in serum. The levels of （ ） ， Results immunoglobulin Ig A IgG and IgM in serum were measured by immune nephelometry. The urinary mercury level of （ ： vs ，P ） individuals in the mercury exposed group was higher than that of the control group median 92.7 13.2 μg/g Cr <0.01 . The +， + +， - + proportion of CD3 CD3CD4 CD3CD19 cells in peripheral blood and serum IgG level in the mercury exposed group （ P ）， - - （ P ） decreased all <0.05 and the serum TNF α and IL 8 levels increased all <0.01 compared with the control group. Urinary - + mercury level was negatively correlated with the proportion of CD3CD19 cells in peripheral blood and serum IgG level in the ［ （r） ， ， P ］， study subjects Spearman correlation coefficient S were −0.21 and −0.31 respectively all <0.05 and positively - - （r ， ， P ） ， correlated with serum TNF α and IL 8 levels S were 0.36 and 0.39 respectively all <0.05 . However the urinary mercury （ P ）， +， + +， level was neither correlated with IgA and IgM levels in serum all >0.05 nor with the proportion of CD3 CD3CD4 + + （ P ） Conclusion CD3CD8 cells in peripheral blood all >0.05 . Occupational exposure to mercury can lead to abnormal ， changes in peripheral blood T lymphocyte subsets B lymphocytes and serum immune factors in workers. The mercury load of occupational mercury exposure workers may impact their immune function.