Ultrastrong lightweight nanocellulose-based composite aerogels with robust superhydrophobicity and durable thermal insulation under extremely environment

Ultra-lightweight porous aerogels based on nanocellulose (NC) have promising applications in various fields such as building insulation, sewage treatment, energy storage, and aerospace. One of the key advantages of these aerogels is their exceptionally low thermal conductivity. Nevertheless, the thermal insulation of NC aerogel (NCA) can deteriorate with changes in temperature and humidity conditions, making it crucial to develop a bulk aerogel that can maintain exceptional thermal insulating properties in harsh environmental conditions. A sustainable and user-friendly approach to synthesizing cellulose/poly(vinyl alcohol) aerogel (CellPA) materials has been developed, which are lightweight, possess good insulating properties, and demonstrate robust superhydrophobicity even in harsh environmental conditions. The CellPA are both exceptionally lightweight and robust, boasting outstanding resistance to combustion while also displaying a thermal conductivity of 36.1 mW m-1 K-1, suggesting they hold great promise for insulation applications. Furthermore, CellPA also exhibits robust superhydrophobicity even under harsh conditions, confirming the homogenous superhydrophobic modification of the biodegradable PVA through chemical methods. The manufacturing of bio-based composite materials with enhanced mechanical and thermal insulation features has gained immense popularity in a broad spectrum of contemporary engineering applications. These composite materials are particularly valuable as a robust, energy-efficient, lightweight, waterproof and flameproof for construction materials.

The role of hyperbaric oxygen in osteoradionecrosis-a prophylactic insight

BACKGROUND

Osteoradionecrosis (ORN) is an uncommon and debilitating consequence of head and neck radiotherapy and hyperbaric oxygen therapy (HBOT) has been advocated for prophylaxis prior to performing dentoalveolar procedures. The aim of this study was to evaluate a prophylactic HBOT protocol and describe the outcomes of susceptible individuals.

METHODS

A retrospective audit of adults who attended the Oral and Maxillofacial Surgery department at the Royal Adelaide Hospital (South Australia) who received dental extractions with a history of radiotherapy to the jaws from 2008 to 2020. Data including demographic information and outcomes of osteoradionecrosis and delayed healing was recorded.

RESULTS

A total of 121 individuals were eligible for case note review; 68.6% of individuals were male and 55.4% were aged over 67 years. Osteoradionecrosis occurred in 9.1% of individuals and delayed healing for 3.3%; fifteen individuals (12.4%) were unable to complete the HBOT protocol. The individuals who were diagnosed with ORN had a significant association with age (P = 0.006) and binary analysis showed alcohol consumption to be a significant predictor.

CONCLUSIONS

Prophylactic HBOT protocol had a lower proportion of individuals diagnosed with ORN and those who were diagnosed were more likely to be younger males and have current alcohol consumption.

A Versatile 2D Cellulose Platform Strategy from Natural Wood Scaffold

A wood cell wall with cellulose as the key scaffold is a natural hierarchical lamellar structure. This wood-derived cellulose scaffold has recently attracted enormous attention and interest, but almost all efforts have been devoted to its whole tissue functionalization. Here, we report the short ultrasonic processing of a wood cellulose scaffold to directly generate 2D cellulose materials. The obtained 2D cellulose nanosheets consist of many highly oriented fibrils densely arranged and can be further converted to ultrathin 2D carbon nanosheets. The nanoparticles, nickel-iron layer double hydroxide nanoflowers, manganese dioxide nanorods, and zinc oxide nanostars, are successfully loaded in the 2D nanosheet, providing a versatile 2D platform strategy for excellent 2D hybrid nanomaterials.

Dual-Network Structured Nanofibrous Membranes with Superelevated Interception Probability for Extrafine Particles

Airborne particulate matter (PM) pollution has caused a public health threat, including nanoscale particles, especially with emerging infectious diseases and indoor and vehicular environmental pollution. However, most existing indoor air filtration units are expensive, energy-intensive, and bulky, and there is an unavoidable trade-off between low-efficiency PM_0.3/pathogen interception, PM removal, and air resistance. Herein, we designed and synthesized a two-dimensional continuous cellulose-sheath/net with a unique dual-network corrugated architecture to manufacture high-efficiency air filters and even N95 particulate face mask. Combined with its sheath/net structured pores (size 100-200 nm) consisting of a cellulose framework (1-100 nm diameter), the cellulose sheath/net filter offers high-efficiency air filtration (>99.5338%, Extrafine particles; >99.9999%, PM_2.5), low-pressure drops, and a robustness quality factor of >0.14 Pa^-1, utilizing their ultralight weight of 30 mg/m² and physical adhesion and sieving behaviors. Simultaneously, masks prepared with cellulose-sheath/net filters are more likely to capture and block smaller particles than the N95 standard. The synthesis of such materials with their nanoscale features and designed macrostructures may suggest new design criteria for a novel generation of high-efficiency air filter media for different applications such as personal protection products and industrial dust removal.

Bioinspired Construction of Micronano Lignocellulose into an Impact Resistance "Wooden Armor" With Bouligand Structure

The demand for advanced safeguards has increased with a rise in terrorism and international conflicts. Traditional impact-resistant glass and ceramics have relatively high performance but have several drawbacks as well, such as inflexibility, heaviness, and high processing energy consumption. Herein, we propose sustainable lignocellulosic duplicates: the Pirarucu scale-inspired structures that can serve as "wood armor" with impressive damage tolerance. By accurately assembling a rigid laminated lignocellulose, with a soft shear-thickened fluid interlayer, into a Bouligand-like structure, the artificial wooden armor exhibits a 10-fold increase in impact resistance. This observation is similar to that of typical engineering materials (e.g., ceramics, glass, and alloys). However, our proposed material structure has the capability of blocking the enormous impact of a bullet while notably having approximately half the density of typical engineering materials. The high durability and damage resistance of wooden armor effectively prevents catastrophic damage when it is impacted upon. The design strategy presents a method for lightweight, high-performance, and sustainable bioinspired materials for special security applications.

Cellulose-Based Hybrid Structural Material for Radiative Cooling

Structural materials with excellent mechanical properties are vitally important for architectural application. However, the traditional structural materials with complex manufacturing processes cannot effectively regulate heat flow, causing a large impact on global energy consumption. Here, we processed a high-performance and inexpensive cooling structural material by bottom-up assembling delignified biomass cellulose fiber and inorganic microspheres into a 3D network bulk followed by a hot-pressing process; we constructed a cooling lignocellulosic bulk that exhibits strong mechanical strength more than eight times that of the pure wood fiber bulk and greater specific strength than the majority of structural materials. The cellulose acts as a photonic solar reflector and thermal emitter, enabling a material that can accomplish 24-h continuous cooling with an average dT of 6 and 8 °C during day and night, respectively. Combined with excellent fire-retardant and outdoor antibacterial performance, it will pave the way for the design of high-performance cooling structural materials.

Artificial Wooden Nacre: A High Specific Strength Engineering Material

Nacre, an organic-inorganic composite biomaterial that forms an ordered multilayer microstructure after years of slow biomineralization, is known as the strongest and toughest material within the mollusc family. Its unique structure provides inspiration for robust artificial engineering materials. Lignocellulose is ultralightweight, abundant, and possesses a high mechanical performance and has been used for ages as a significant renewable raw material in wooden engineering composites. However, the inherent lack of mechanical properties of current wooden composites associated with the fragile microstructure has limited their applications in advanced engineering materials. Here, we develop a large-size ultralightweight artificial "wood nacre" with an ordered layer structure through a fast and scalable "mechanical/chemical mineralization and assembly" approach. The millimeter-thick artificial wooden nacre mimics the stratified construction of natural nacre, resulting in a bulk hybrid material that can achieve almost the same strength as natural nacre while consisting of only one-sixth of the total inorganic content of natural nacre. The specific strength and toughness of the artificial wooden nacre is even superior to engineering alloy materials (such as Cu and Fe). This approach represents an efficient strategy for the mass production of lightweight sustainable structural materials with high strength and toughness.

Processing Lignocellulose-Based Composites into an Ultrastrong Structural Material

Natural lignocellulose has been a significant renewable raw material attributable to its high specific mechanical performance, compared to the benefits of traditional reinforcing fibers. However, the unsatisfactory mechanical performance of lignocellulose-based materials has limited applications in many advanced engineering domains. Herein, we demonstrate that layered bulk delignified nanolignocellulose/brushite composites with a multifold increase in strength and toughness. Our procedure contains the partially removable lignin and hemicellulose from the nanolignocellulose and the precipitating process of brushite on the nanolignocellulose surface via the mechanochemical process and flow-directed assembly followed by hot-pressing, resulting in the complete toppling of cell walls and the densification of the nanolignocellulose/brushite composites with highly ordered layered structures. This composite exhibits an ultrastrong specific strength 1.8-4.4 times higher than that of modified lignocellulose-based materials, which surpasses that of most natural structural materials and some metals and alloys, opening a path for production of ultrastrong lignocellulose-based load-bearing materials in practical applications by various farming and forestry surplus operations.

Effect of carbon fiber addition on the electromagnetic shielding properties of carbon fiber/polyacrylamide/wood based fiberboards

Carbon fiber (CF) reinforced polyacrylamide/wood fiber composite boards are fabricated by mechanical grind-assisted hot-pressing, and are used for electromagnetic interference (EMI) shielding. CF with an average diameter of 150 nm is distributed on wood fiber, which is then encased by polyacrylamide. The CF/polyacrylamide/wood fiber (CPW) composite exhibits an optimal EMI shielding effectiveness (SE) of 41.03 dB compared to that of polyacrylamide/wood fiber composite (0.41 dB), which meets the requirements of commercial merchandise. Meanwhile, the CPW composite also shows high mechanical strength. The maximum modulus of rupture (MOR) and modulus of elasticity (MOE) of CPW composites are 39.52 MPa and 5823.15 MPa, respectively. The MOR and MOE of CPW composites increased by 38% and 96%, respectively, compared to that of polyacrylamide/wood fiber composite (28.64 and 2967.35 MPa).

The properties of fibreboard based on nanolignocelluloses/CaCO3/PMMA composite synthesized through mechano-chemical method

The purpose of this study was to develop a rapid and green method for the synthesis of lignocelluloses-based materials with superior mechanical properties. Samples were produced by hot-pressed method using different concentrations of CaCO₃ and poly (methyl methacrylate) particles-filled nanolignocelluloses composites which was synthesized through mechano-chemical method. Poly (methyl methacrylate) and CaCO₃ nanoparticles have been used as nanofillers. Bending strength, elasticity modulus, and dimensional stability, thermal properties of the developed lignocelluloses-based composites were determined. In view of the experimental results, it is found that the composites materials have good mechanical, dimensional stability, and thermal properties which enhanced as the filler loading increased. Thus, herein described lignocelluloses-based materials showed important characteristics to be concluded that these composites are suitable to be used for the design of flooring and construction systems.

High Mechanical Property of Laminated Electromechanical Sensors by Carbonized Nanolignocellulose/Graphene Composites

Although widely used in nanocomposites, the effect of embedding graphene in carbonized nanolignocellulose substrates is less clear. We added graphene to a carbonized nanolignocellulose to change its mechanical and electromechanical properties. Here, the laminated carbonized nanolignocellulose/graphene composites were fabricated by carbonizing the nanolignocellulose/graphene composites prepared through mechanochemistry and flow-directed assembly process. The resulting composites exhibit excellent mechanical property with the ultimate bending strength of 25.6 ± 4.2 MPa. It is observed reversible electrical resistance change in these composites with strain, which is associated with the tunneling conduction model. This type of high-strength conductive composite has great potential applications in load-bearing electromechanical sensors.

Preparation of High Mechanical Performance Nano-Fe₃O₄/Wood Fiber Binderless Composite Boards for Electromagnetic Absorption via a Facile and Green Method

Fe₃O₄/wood fiber composites are prepared with a green mechanical method using only distilled water as a solvent without any chemical agents, and then a binderless composite board with high mechanical properties is obtained via a hot-press for electromagnetic (EM) absorption. The fibers are connected by hydrogen bonds after being mechanically pretreated, and Fe₃O₄ nanoparticles (NPs) are attached to the fiber surface through physical adsorption. The composite board is bonded by an adhesive, which is provided by the reaction of fiber composition under high temperature and pressure. The Nano-Fe₃O₄/Fiber (NFF) binderless composite board shows remarkable microwave absorption properties and high mechanical strength. The optional reflection loss (RL) of the as-prepared binderless composite board is -31.90 dB. The bending strength of the NFF binderless composite board is 36.36 MPa with the addition of 6% nano-Fe₃O₄, the modulus of elasticity (MOE) is 6842.16 MPa, and the internal bond (IB) strength is 0.81 MPa. These results demonstrate that magnetic nanoparticles are deposited in binderless composite board by hot pressing, which is the easiest way to produce high mechanical strength and EM absorbers.

Cellulose Fibers Constructed Convenient Recyclable 3D Graphene-Formicary-like δ-Bi2O3 Aerogels for the Selective Capture of Iodide

Radioiodine is highly radioactive and acutely toxic, which can be a serious health threat, and requires effective control. To fully utilize an adsorbent and reduce the overall production cost, successive recycling applications become necessary. Here, 3D formicary-like δ-Bi₂O₃ (FL-δ-Bi₂O₃) aerogel adsorbents were synthesized using a one-pot hydrothermal method. In this hybrid structure, abundant flowerlike δ-Bi₂O₃ (MR-δ-Bi₂O₃) microspheres were inlaid into the interconnected ant nest channel, forming a 3D hierarchical structure, which is applied as an efficient adsorbent with easy recovery for radioiodine removal. Notably, the FL-δ-Bi₂O₃ aerogel adsorbent exhibited a very high uptake capacity of 2.04 mmol/g by forming an insoluble Bi₄I₂O₅ phase. Moreover, the FL-δ-Bi₂O₃ worked in a wide pH range of 4-10 and displayed fast uptake kinetics and excellent selectivity due to the 3D porous interconnected network and larger specific surface area. Importantly, the recycling process is easy, using only tweezers to directly move the 3D aerogel adsorbents from one reaction system to another. Therefore, the FL-δ-Bi₂O₃ aerogel may be a promising practical adsorbent for the selective capture of radioactive iodide.

Bio-Inspired nacre-like nanolignocellulose-poly (vinyl alcohol)-TiO2 composite with superior mechanical and photocatalytic properties

Nacre, the gold standard for biomimicry, provides an excellent example and guideline for assembling high-performance composites. Inspired by the layered structure and extraordinary strength and toughness of natural nacre, nacre-like nanolignocellulose/poly (vinyl alcohol)/TiO₂ composites possessed the similar layered structure of natural nacre were constructed through hot-pressing process. Poly (vinyl alcohol) and TiO₂ nanoparticles have been used as nanofillers to improve the mechanical performance and synchronously endow the superior photocatalytic activity of the composites. This research would be provided a promising candidate for the photooxidation of volatile organic compounds also combined with outstanding mechanical property.

Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy

Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy.

Downregulation of hepatic acyl-CoA:diglycerol acyltransferase in chronic renal failure

Chronic renal failure (CRF) is associated with hypertriglyceridemia and elevated plasma VLDL and IDL concentrations. These events can be due to either increased production or depressed catabolism of triglyceride-rich lipoproteins. Several studies have documented downregulation of lipoprotein lipase, hepatic triglyceride lipase, and the VLDL receptor, leading to depressed clearance and elevated plasma concentration of triglyceride-rich lipoproteins and their remnants in CRF. However, the effect of CRF on the triglyceride biosynthetic pathway has not been explored. Diglycerol acyltransferase (DGAT) is a microsomal enzyme that joins acyl-CoA to 1,2 diacylglycerol and, as such, constitutes the final step in triglyceride biosynthesis. Two distinct forms of DGAT (DGAT-1 and -2) have thus far been identified. The present study was undertaken to examine the effect of CRF on DGAT gene expression and activity in the liver, which is the source of endogenous triglycerides in the circulation. Male Sprague-Dawley rats were studied 8 wk after 5/6 nephrectomy (CRF) or sham operation. DGAT-1 and DGAT-2 mRNA abundance and DGAT activity were quantified. The CRF group showed reduced creatinine clearance, elevated plasma triglycerides, and VLDL concentrations. This was accompanied by significant reductions in hepatic DGAT-2 mRNA abundance (P < 0.01) and total DGAT activity (P < 0.1), pointing to diminished hepatic triglyceride production capacity in CRF animals. In conclusion, CRF results in significant downregulation of hepatic DGAT gene expression and activity. Given the critical role of DGAT in triglyceride biosynthesis, the present study points to diminished, not increased, hepatic triglyceride synthetic capacity in CRF rats.

Microdissection and microcloning of rye (Secale cereale L.) chromosome 1R

Chromosome 1R was microdissected and collected from mitotic metaphase spreads of rye (Secale cereale L.) by using glass needles. The isolated chromosomes were amplified in vitro by Sau3A linker adaptor-mediated polymerase chain reaction (PCR). After amplification, the presence of rye-specific DNA was verified by Southern hybridization. The second-round PCR products from five 1R chromosomes were cloned into a plasmid vector to create a chromosome-specific library, which produced approximately 220,000 recombinant clones. Characterization of the microclone library showed that the 172 clones evaluated ranged in size from 300-1800 bp with an average size of 950 bp, of which approximately 42% were medium/high copy and 58% were low/unique copy clones. Chromosome in situ hybridization confirmed that the PCR products from microdissected chromosomes originated from chromosome 1R, indicating that many chromosome 1R-specific sequences were present in the library.

Myocardial bridges: effect of propranolol on systolic compression

Myocardial bridges may exert an ischemic effect on the myocardium and often warrant therapy including surgical correction in selected cases. Decrease in systolic compression after the administration of propranolol has not been reported. We report a patient who demonstrated angiographic systolic compression of the coronary artery with subsequent improvement on treatment with propranolol. The reduction in severity of systolic compression caused by propranolol may be due to the negative inotropic effect and perhaps from an increase in coronary artery vascular tone secondary to a beta-blocker with unopposed alpha effect. Further studies are needed to assess the efficacy of beta-blocker therapy in patients with myocardial bridging and the use of intravenous propranolol at the time of coronary angiography may have practical implications in selecting drug therapy for patients with symptomatic myocardial bridging.