A Bioinspired Gradient Design Strategy for Cellulose-Based Electromagnetic Wave Absorbing Structural Materials.

Cellulose nanofiber (CNF) possesses excellent intrinsic properties, and many CNF-based high-performance structural and functional materials have been developed recently. However, the coordination of the mechanical properties and functionality is still a considerable challenge. Here, a CNF-based structural material is developed by a bioinspired gradient structure design using hollow magnetite nanoparticles and the phosphorylation-modified CNF as building blocks, which simultaneously achieves a superior mechanical performance and electromagnetic wave absorption (EMA) ability. Benefiting from the gradient design, the flexural strength of the structural material reached ∼205 MPa. Meanwhile, gradient design improves impedance matching, contributing to the high EMA ability (-59.5 dB) and wide effective absorption width (5.20 GHz). Besides, a low coefficient of thermal expansion and stable storage modulus was demonstrated as the temperature changes. The excellent mechanical, thermal, and EMA performance exhibited great potential for application in stealth equipment and electromagnetic interference protecting electronic packaging materials.

Simultaneously Strengthening and Toughening All-Natural Structural Materials via 3D Nanofiber Network Interfacial Design.

Constructing structural materials from sustainable raw materials is considered an efficient way to reduce the potential threat posed by plastics. Nevertheless, challenges remain regarding combining excellent mechanical and thermal properties, especially the balance of strength and toughness. Here, we report a 3D nanofiber network interfacial design strategy to strengthen and toughen all-natural structural materials simultaneously. The introduced protonated chitosan at the interface between the surface oxidized 3D nanonetwork of bacterial cellulose forms the interfacial interlocking structure of nanonetworks, achieving a robust physical connection and providing enough physical contact sites for chemical crosslinking. The obtained sustainable structural material successfully integrates excellent mechanical and thermal properties on the nanoscale of cellulose nanofibers, such as light weight, high strength, and superior thermal expansion coefficient. The relationship between structural design and comprehensive mechanical property improvement is analyzed in detail, providing a universal perspective to design sustainable high-performance structural materials from nanoscale building blocks.

An All-Natural Wood-Inspired Aerogel.

The oriented pore structure of wood endows it with a variety of outstanding properties, among which the low thermal conductivity has attracted researchers to develop wood-like aerogels as excellent thermal insulation materials. However, the increasing demands of environmental protection have put forward new and strict requirements for the sustainability of aerogels. Here, we report an all-natural wood-inspired aerogel consisting of all-natural ingredients and develop a method to activate the surface-inert wood particles to construct the aerogel. The obtained wood-inspired aerogel has channel structure similar to that of natural wood, endowing it with superior thermal insulation properties to most existing commercial sponges. In addition, remarkable fire retardancy and complete biodegradability are integrated. With the above outstanding performances, this sustainable wood-inspired aerogel will be an ideal substitute for the existing commercial thermal insulation materials.

Tough and Moldable Sustainable Cellulose-Based Structural Materials via Multiscale Interface Engineering.

All-natural materials derived from cellulose nanofibers (CNFs) are expected to be used to replace engineering plastics and have attracted much attention. However, the lack of crack extension resistance and 3D formability of nanofiber-based structural materials hinders their practical applications. Here, a multiscale interface engineering strategy is reported to construct high-performance cellulose-based materials. The sisal microfibers are surface treated to expose abundant active CNFs with positive charges, thereby enhancing their interfacial combination with the negatively charged CNFs. The robust multiscale dual network enables easy molding of multiscale cellulose-based structural materials into complex 3D special-shaped structures, resulting in nearly twofold and fivefold improvements in toughness and impact resistance compared with those of CNFs-based materials. Moreover, this multiscale interface engineering strategy endows cellulose-based structural materials with better comprehensive performance than petrochemical-based plastics and broadens cellulose's potential for lightweight applications as structural materials with lower environmental effects.

Ultrastrong, Thermally Stable, and Food-Safe Seaweed-Based Structural Material for Tableware.

Widely used disposable plastic tableware is usually buried or directly discharged into the natural environment after using, which poses potential threats to the natural environment and human health. To solve this problem, nondegradable plastic tableware needs to be replaced by tableware composed of biodegradable structural materials with both food safety and the excellent mechanical and thermal properties. Here, a food-safe sargassum cellulose nanofiber (SCNF) is extracted from common seaweed in an efficient and low energy consuming way under mild reaction conditions. Then, by assembling the SCNF into a dense bulk material, a strong sargassum cellulose nanofiber structural material (SCNSM) with high strength (283 MPa) and high thermal stability (>160 °C) can be prepared. The SCNSM also possesses good machinability, which can be processed into tableware with different shapes, e.g., knives and forks. The overall performance of the SCNSM-based tableware is better than commercial plastic, wood-based, and poly(lactic acid) tableware, which shows great application potential in the tableware field.

Nacre-Inspired Bacterial Cellulose/Mica Nanopaper with Excellent Mechanical and Electrical Insulating Properties by Biosynthesis.

The exploration of extreme environments has become necessary for understanding and changing nature. However, the development of functional materials suitable for extreme conditions is still insufficient. Herein, a kind of nacre-inspired bacterial cellulose (BC)/synthetic mica (S-Mica) nanopaper with excellent mechanical and electrical insulating properties that has excellent tolerance to extreme conditions is reported. Benefited from the nacre-inspired structure and the 3D network of BC, the nanopaper exhibits excellent mechanical properties, including high tensile strength (375 MPa), outstanding foldability, and bending fatigue resistance. In addition, S-Mica arranged in layers endows the nanopaper with remarkable dielectric strength (145.7 kV mm-1 ) and ultralong corona resistance life. Moreover, the nanopaper is highly resistant to alternating high and low temperatures, UV light, and atomic oxygen, making it an ideal candidate for extreme environment-resistant materials.

Prevalence of gene mutations in a Chinese 46,XY disorders of sex development cohort detected by targeted next-generation sequencing.

46,XY disorders of sex development (DSD) is characterized by incomplete masculinization genitalia, with gonadal dysplasia and with/without the presence of Müllerian structures. At least 30 genes related to 46,XY DSD have been found. However, the clinical phenotypes of patients with different gene mutations overlap, and accurate diagnosis relies on gene sequencing technology. Therefore, this study aims to determine the prevalence of pathogenic mutations in a Chinese cohort with 46,XY DSD by the targeted next-generation sequencing (NGS) technology. Eighty-seven 46,XY DSD patients were enrolled from the Peking Union Medical College Hospital (Beijing, China). A total of fifty-four rare variants were identified in 60 patients with 46,XY DSD. The incidence of these rare variants was approximately 69.0% (60/87). Twenty-five novel variants and 29 reported variants were identified. Based on the American College of Medical Genetics and Genomics (ACMG) guidelines, thirty-three variants were classified as pathogenic or likely pathogenic variants and 21 variants were assessed as variants of uncertain significance. The overall diagnostic rate was about 42.5% based on the pathogenic and likely pathogenic variants. Androgen receptor (AR), steroid 5-alpha-reductase 2 (SRD5A2) and nuclear receptor subfamily 5 Group A member 1 (NR5A1) gene variants were identified in 21, 13 and 13 patients, respectively. The incidence of these three gene variants was about 78.3% (47/60) in patients with rare variants. It is concluded that targeted NGS is an effective method to detect pathogenic mutations in 46,XY DSD patients and AR, SRD5A2, and NR5A1 genes were the most common pathogenic genes in our cohort.

Predictive factors for pituitary response to pulsatile GnRH therapy in patients with congenital hypogonadotropic hypogonadism.

Pulsatile gonadotropin-releasing hormone (GnRH) may induce spermatogenesis in most patients with congenital hypogonadotropic hypogonadism (CHH) by stimulating gonadotropin production, while the predictors for a pituitary response to pulsatile GnRH therapy were rarely investigated. Therefore, the aim of our study is to investigate predictors of the pituitary response to pulsatile GnRH therapy. This retrospective cohort study included 82 CHH patients who received subcutaneous pulsatile GnRH therapy for at least 1 month. Patients were categorized into poor or normal luteinizing hormone (LH) response subgroups according to their LH level (LH <2 IU l-1 or LH ≥2 IU l-1) 1 month into pulsatile GnRH therapy. Gonadotropin and testosterone levels, testicular size, and sperm count were compared between the two subgroups before and after GnRH therapy. Among all patients, LH increased from 0.4 ± 0.5 IU l-1 to 7.5 ± 4.4 IU l-1 and follicle-stimulating hormone (FSH) increased from 1.1 ± 0.9 IU l-1 to 8.8 ± 5.3 IU l-1. A Cox regression analysis showed that basal testosterone level (ß = 0.252, P = 0.029) and triptorelin-stimulated FSH60min(ß = 0.518, P = 0.01) were two favorable predictors for pituitary response to GnRH therapy. Nine patients (9/82, 11.0%) with low LH response to GnRH therapy were classified into the poor LH response subgroup. After pulsatile GnRH therapy, total serum testosterone level was 39 ± 28 ng dl-1 versus 248 ± 158 ng dl-1 (P = 0.001), and testicular size was 4.0 ± 3.1 ml versus 7.9 ± 4.5 ml (P = 0.005) in the poor and normal LH response subgroups, respectively. It is concluded that higher levels of triptorelin-stimulated FSH60minand basal total serum testosterone are favorable predictors of pituitary LH response to GnRH therapy.

Pulsatile gonadotropin-releasing hormone therapy is associated with earlier spermatogenesis compared to combined gonadotropin therapy in patients with congenital hypogonadotropic hypogonadism.

Both pulsatile gonadotropin-releasing hormone (GnRH) infusion and combined gonadotropin therapy (human chorionic gonadotropin and human menopausal gonadotropin [HCG/HMG]) are effective to induce spermatogenesis in male patients with congenital hypogonadotropic hypogonadism (CHH). However, evidence is lacking as to which treatment strategy is better. This retrospective cohort study included 202 patients with CHH: twenty had received pulsatile GnRH and 182 had received HCG/HMG. Patients had received therapy for at least 12 months. The total follow-up time was 15.6 ± 5.0 months (range: 12-27 months) for the GnRH group and 28.7 ± 13.0 months (range: 12-66 months) for the HCG/HMG group. The median time to first sperm appearance was 6 months (95% confidence interval [CI]: 1.6-10.4) in the GnRH group versus 18 months (95% CI: 16.4-20.0) in the HCG/HMG group (P < 0.001). The median time to achieve sperm concentrations ≥5 × 10 6 ml-1 was 14 months (95% CI: 5.8-22.2) in the GnRH group versus 27 months (95% CI: 18.9-35.1) in the HCG/HMG group (P < 0.001), and the median time to concentrations ≥10 × 10 6 ml-1 was 18 months (95% CI: 10.0-26.0) in the GnRH group versus 39 months (95% CI unknown) in the HCG/HMG group. Compared to the GnRH group, the HCG/HMG group required longer treatment periods to achieve testicular sizes of ≥4 ml, ≥8 ml, ≥12 ml, and ≥16 ml. Sperm motility (a + b + c percentage) evaluated in semen samples with concentrations >1 × 10 6 ml-1 was 43.7% ± 20.4% (16 samples) in the GnRH group versus 43.2% ± 18.1% (153 samples) in the HCG/HMG group (P = 0.921). Notably, during follow-up, the GnRH group had lower serum testosterone levels than the HCG/HMG group (8.3 ± 4.6 vs 16.2 ± 8.2 nmol l-1 , P < 0.001). Our study found that pulsatile GnRH therapy was associated with earlier spermatogenesis and larger testicular size compared to combined gonadotropin therapy. Additional prospective randomized studies would be required to confirm these findings.