A Paternò-Büchi Reaction of Aromatics with Quinones under Visible Light Irradiation.

Reported herein is a Paternò-Büchi reaction of aromatic double bonds with quinones under visible light irradiation. The reactions of aromatics with quinones exposed to blue LED irradiation yielded oxetanes at -78 °C, which was attributed to both the activation of double bonds in aromatics and the stabilization of oxetanes by thiadiazole, oxadiazole, or selenadiazole groups. The addition of Cu(OTf)2 to the reaction system at room temperature resulted in the formation of diaryl ethers via the copper-catalyzed ring opening of oxetanes in situ. Notably, the substrate scope was extended to general aromatics.

Older Adults' Response to Color Visibility in Indoor Residential Environment Using Eye-Tracking Technology.

Older adults spend relatively more time in indoor residential environments than young people. As their visual and cognitive abilities decline, they experience a high risk of accidents in indoor environments; thus, understanding their gaze behavior while considering cognitive capacity is essential in preventing potential accidents and planning for aging-friendly environments. The purpose of this study was to examine whether the use of color in living environments affects the visual attention of older adults. The following two experiments were conducted using eye-tracking technology: Experiment 1: Older adults' gaze behaviors were measured while viewing four images consisting of nine sets of door-door frames with different color combinations of safety colors, black and white; and Experiment 2: Based on results from Experiment 1, images of simulated living environments were created, and older adults' gaze behaviors were measured while viewing eight images in which two door colors were applied to verify spatial color visibility. Their cognitive state represented by the Mini-Mental State Examination (MMSE) was then compared with their gaze behavior. The results show that: (a) participants paid more attention to doors with color combinations including red (red-black and white-red) and remained longer on the red-black combination; (b) older adults looked at red-black doors faster than white doors in the same position; (c) the dwell time on a red-black door was longer than on that of the corresponding position of a white door; and (d) based on participants' MMSE values, the gaze behaviors of the group with low cognition were less focused and observable than those of the group with normal cognition. The results of this study are significant in that they reveal that indoor color can improve the visibility of elements that can impact safety in the living environments of older adults and enhance their quality of life.

Identified lung adenocarcinoma metabolic phenotypes and their association with tumor immune microenvironment.

BACKGROUND: Lung adenocarcinoma (LUAD), a subtype of non-small cell lung cancer (NSCLC), causes high mortality around the world. Previous studies have suggested that the metabolic pattern of tumor is associated with tumor response to immunotherapy and patient's survival outcome. Yet, this relationship in LUAD is still unknown. METHODS: Therefore, in this study, we identified the immune landscape in different tumor subtypes classified by metabolism-related genes expression with a large-scale dataset (tumor samples, n = 2181; normal samples, n = 419). We comprehensively correlated metabolism-related phenotypes with diverse clinicopathologic characteristics, genomic features, and immunotherapeutic efficacy in LUAD patients. RESULTS: And we confirmed tumors with activated lipid metabolism tend to have higher immunocytes infiltration and better response to checkpoint immunotherapy. This work highlights the connection between the metabolic pattern of tumor and tumor immune infiltration in LUAD. A scoring system based on metabolism-related gene expression is not only able to predict prognosis of patient with LUAD but also applied to pan-cancer. LUAD response to checkpoint immunotherapy can also be predicted by this scoring system. CONCLUSIONS: This work revealed the significant connection between metabolic pattern of tumor and tumor immune infiltration, regulating LUAD patients' response to immunotherapy.

Naringin alleviates H2O2-induced apoptosis via the PI3K/Akt pathway in rat nucleus pulposus-derived mesenchymal stem cells.

Purpose: To investigate the protective effect of naringin (Nar) on H2O2-induced apoptosis of nucleus pulposus-derived mesenchymal stem cells (NPMSC) and the potential mechanism in this process. Methods: Rat NPMSC were cultured in MSC culture medium or culture medium with different concentrations of H2O2. Nar or the combination of Nar and LY294002 was added into the culture medium to investigate the effects of Nar. Cell viability was evaluated by cell counting kit-8 (CCK-8) assay. The apoptosis rate was determined using Annexin V/PI dual staining and terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) assays. Additionally, the levels of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were analyzed by flow cytometry. ATP level in NPMSC was analyzed via ATP detection kit. Mitochondrial ultrastructure change was observed through transmission electron microscope (TEM). Levels of apoptosis-associated molecules (cleaved caspase-3, Bax and Bcl-2) were evaluated via RT-PCR and western blot, respectively. Results: The cells isolated from NP met the criteria for MSC. H2O2 significantly promoted NPMSC apoptosis in a dose and time-dependent manner. Nar showed no cytotoxicity effect on NPMSC up to a concentration of 100 µM for 24 h. Nar exhibited protective effects against H2O2-induced NPMSC apoptosis including apoptosis rate, expressions of proapoptosis and antiapoptosis related genes and protein. Nar could also alleviate H2O2-induced mitochondrial dysfunction of increased mitochondrial ROS production, reduced MMP, decreased intracellular ATP and mitochondrial ultrastructure change. However, these protected effects were inhibited after LY294002 treatment. Conclusions: Our results demonstrated that Nar efficiently attenuated H2O2-induced NPMSC apoptosis and mitochondrial dysfunction. The activation of ROS-mediated PI3K/Akt pathway may be the potential mechanism in this process.

The effect of intervertebral disc degenerative change on biological characteristics of nucleus pulposus mesenchymal stem cell: an in vitro study in rats.

Purpose: To evaluate the change on biological characteristics of mesenchymal stem cell (MSC) derived from normal and degenerative intervertebral disc (IVD). Methods: MSC was isolated from normal and degenerative IVD rat model. Immunophenotype detected by flow cytometric analysis, expression of stemness genes determined by reverse-transcription polymerase chain reaction (RT-PCR) and osteogenic, adipogenic and chondrogenic differentiation were compared between MSC derived from normal IVD (N-NPMSC) and degenerative IVD (D-NPMSC). The biological characteristics including cell proliferation, colony formation, apoptosis, caspase-3 activity and mRNA and protein expressions of hypoxia inducible factor-1α (HIF-1α), glucose transporter 1 (GLUT-1), vascular endothelial growth factor (VEGF), silent information regulator protein 1 (SIRT1) and silent information regulator protein 6 (SIRT6) were compared between N-NPMSC and D-NPMSC. Results: Both of N-NPMSC and D-NPMSC highly expressed CD105, CD90 and CD73, and lower expressed CD34 and CD45. There was no significant difference in cell morphology and multipotent differentiation ability between N-NPMSC and D-NPMSC. D-NPMSC showed significantly lower expressions of stemness genes, cell proliferation and colony formation ability. D-NPMSC also exhibited increased cell apoptosis rate and caspase-3 expression, and significantly lower expressions of HIF-1α, GLUT-1, VEGF, SIRT1 and SIRT6 in mRNA and protein levels compared with N-NPMSC. Conclusions: N-NPMSC showed significantly higher proliferation rate, better colony forming and stemness maintenance ability, whereas reduced cell apoptosis rate compared with D-NPMSC. HIF-1α-mediated signal pathway may be involved in the regulation of NPMSC proliferation. These findings indicated that degenerative change of IVD should be taken into account when selecting a source of NPMSC for clinical application.

[Application of nocturnal penile tumescence test in the diagnosis of erectile dysfunction].

ED is a common male disease, often caused by neurological, vascular or psychological factors, and the diagnostic methods for ED vary widely. The nocturnal penile tumescence test (NPT) by RigiScan is an objective assessment method used mainly to detect ED and has gained a wide clinical application in recent years. This review focuses on the application value of the six RigiScan parameters in the diagnosis of ED, namely, the number of erections, total erection time, event rigidity of tip/base, event tumescence of tip/base, tumescence activated unit and rigidity activated unit, aiming to provide some help to clinicians and researchers with the application of NPT.

[Progress in the study of new cancer target Cdk5 and its inhibitors].

Cyclin-dependent kinase-5(Cdk5) is a kind of Ser/Thr kinases in the signaling pathway, which regulates the neural development. The recent studies have confirmed that hyperactivation of Cdk5 is closely associated with the evolution, progression and apoptosis of tumors. The Cdk5 inhibitors have been extensively studied in the drug discovery against cancer. The structure features of these inhibitors and molecular mechanisms of their activities have provided clues for the drug development. In the second generation Cdk5 inhibitors, the ATP-binding pocket, a highly conserved site, has been targeted in the drug design in most cases. In addition, a growing number of peptides has been generated by targeting the protein/protein interfaces of Cdk5.

[Chemical Constituents of n-Butanol Extract of Myrothecium verrucaria].

Objective: To study the chemical constituents of n-butanol extract in the broth of Myrothecium verrucaria. Methods: The chemical constituents were isolated,purified and identified by various chromatographic and spectral techniques. Results: 14 compounds were isolated and identified from n-butanol extracts of Myrothecium verrucaria broth. They were identified as cyclo-( Pro-Phe)( 1),cyclo-( 4-OH-Pro-Phe)( 2),cyclo-( 4-OH-Pro-Leu)( 3),cyclo-( Ala-Pro)( 4),cyclo-( 4-methyl-Pro-9-propyl-Gly)( 5),cyclo-( Pro-Gly)( 6),cyclo-( Phe-Gly)( 7),cyclo-( Leu-Leu)( 8),N-acetyl tryptamine( 9),N-( 2-phenylethyl) acetamide( 10),N-( 2-hydroxyphenethyl) acetamide( 11),N-( 4-hydroxyphenethyl) acetamide( 12),uracil( 13) and thymine( 14). Conclusion: Compounds 1 ~ 14 are obtained from the strain Myrothecium verrucaria for the first time.

Highly Regular Layered Structure via Dual-Spatially-Confined Alignment of Nanosheets Enables High-Performance Nanocomposites.

Assembling ultrathin nanosheets into layered structure represents one promising way to fabricate high-performance nanocomposites. However, how to minimize the internal defects of the layered assemblies to fully exploit the intrinsic mechanical superiority of nanosheets remains challenging. Here, a dual-scale spatially confined strategy for the co-assembly of ultrathin nanosheets with different aspect ratios into a near-perfect layered structure is developed. Large-aspect-ratio (LAR) nanosheets are aligned due to the microscale confined space of a flat microfluidic channel, small-aspect-ratio (SAR) nanosheets are aligned due to the nanoscale confined space between adjacent LAR nanosheets. During this co-assembly process, SAR nanosheets can flatten LAR nanosheets, thus reducing wrinkles and pores of the assemblies. Benefiting from the precise alignment (orientation degree of 90.74%) of different-sized nanosheets, efficient stress transfer between nanosheets and interlayer matrix is achieved, resulting in layered nanocomposites with multiscale mechanical enhancement and superior fatigue durability (100 000 bending cycles). The proposed co-assembly strategy can be used to orderly integrate high-quality nanosheets with different sizes or diverse functions toward high-performance or multifunctional nanocomposites.

Novel subtype of obesity influencing the outcomes of sleeve gastrectomy: Familial aggregation of obesity.

BACKGROUND: Differences in the preoperative characteristics and weight loss outcomes after sleeve gastrectomy (SG) between patients with familial aggregation of obesity (FAO) and patients with sporadic obesity (SO) have not been elucidated. AIM: To explore the impact of SG on weight loss and the alleviation of obesity-related comorbidities in individuals with FAO. METHODS: A total of 193 patients with obesity who underwent SG were selected. Patients with FAO/SO were matched 1:1 by propensity score matching and were categorized into 4 groups based on the number of first-degree relatives with obesity (1SO vs 1FAO, 2SO vs 2FAO). The baseline characteristics, weight loss outcomes, prevalence of obesity-related comorbidities and incidence of major surgery-related complications were compared between groups. RESULTS: We defined FAO as the presence of two or more first-degree relatives with obesity. Patients with FAO did not initially show significant differences in baseline data, short-term postoperative weight loss, or obesity-related comorbidities when compared to patients with SO preoperatively. However, distinctions between the two groups became evident at the two-year mark, with statistically significant differences in both percentage of total weight loss (P = 0.006) and percentage of excess weight loss (P < 0.001). The FAO group exhibited weaker remission of type 2 diabetes mellitus (T2DM) (P = 0.031), hyperlipidemia (P = 0.012), and non-alcoholic fatty liver disease (NAFLD) (P = 0.003) as well as a lower incidence of acid reflux (P = 0.038). CONCLUSION: FAO patients is associated with decreased mid-to-long-term weight loss outcomes; the alleviation of T2DM, hyperlipidemia and NAFLD; and decreased incidence of acid reflux postoperatively.

SR9009 attenuates inflammation-related NPMSC pyroptosis and IVDD through NR1D1/NLRP3/IL-1ß pathway.

Intervertebral disc is a highly rhythmical tissue. As a key factor linking biorhythm and inflammatory response, the shielding effect of NR1D1 in the process of intervertebral disc degeneration remains unclear. Here, we first confirmed that NR1D1 in the nucleus pulposus tissue presents periodic rhythmic changes and decreases in expression with intervertebral disc degeneration. Second, when NR1D1 was activated by SR9009 in vitro, NLRP3 inflammasome assembly and IL-1ß production were inhibited, while ECM synthesis was increased. Finally, the vivo experiments further confirmed that the activation of NR1D1 can delay the process of disc degeneration to a certain extent. Mechanistically, we demonstrate that NR1D1 can bind to IL-1ß and NLRP3 promoters, and that the NR1D1/NLRP3/IL-1ß pathway is involved in this process. Our results demonstrate that the activation of NR1D1 can effectively reduce IL-1ß secretion, alleviate LPS-induced NPMSC pyroptosis, and protect ECM degeneration.

A TGF-ß signaling-related lncRNA signature for prediction of glioma prognosis, immune microenvironment, and immunotherapy response.

AIMS: The dysregulation of TGF-ß signaling is a crucial pathophysiological process in tumorigenesis and progression. LncRNAs have diverse biological functions and are significant participants in the regulation of tumor signaling pathways. However, the clinical value of lncRNAs related to TGF-ß signaling in glioma is currently unclear. METHODS: Data on glioma's RNA-seq transcriptome, somatic mutation, DNA methylation data, and clinicopathological information were derived from the CGGA and TCGA databases. A prognostic lncRNA signature was constructed by Cox and LASSO regression analyses. TIMER2.0 database was utilized to deduce immune infiltration characteristics. "ELMER v.2" was used to reconstruct TF-methylation-gene regulatory network. Immunotherapy and chemotherapy response predictions were implemented by the TIDE algorithm and GDSC database, respectively. In vitro and in vivo experiments were conducted to verify the results and clarify the regulatory mechanism of lncRNA. RESULTS: In glioma, a TGF-ß signaling-related 15-lncRNA signature was constructed, including AC010173.1, HOXA-AS2, AC074286.1, AL592424.1, DRAIC, HOXC13-AS, AC007938.1, AC010729.1, AC013472.3, AC093895.1, AC131097.4, AL606970.4, HOXC-AS1, AGAP2-AS1, and AC002456.1. This signature proved to be a reliable prognostic tool, with high risk indicating an unfavorable prognosis and being linked to malignant clinicopathological and genomic mutation traits. Risk levels were associated with different immune infiltration landscapes, where high risk was indicative of high levels of macrophage infiltration. In addition, high risk also suggested better immunotherapy and chemotherapy response. cg05987823 was an important methylation site in glioma progression, and AP-1 transcription factor family participated in the regulation of signature lncRNA expression. AGAP2-AS1 knockdown in in vitro and in vivo experiments inhibited the proliferation, migration, and invasion of glioma cells, as well as the growth of glioma, by downregulating the expression levels of NF-κB and ERK 1/2 in the TGF-ß signaling pathway. CONCLUSIONS: A prognostic lncRNA signature of TGF-ß signaling was established in glioma, which can be used for prognostic judgment, immune infiltration status inference, and immunotherapy response prediction. AGAP2-AS1 plays an important role in glioma progression.

Rapid screening for Chlamydia trachomatis infection by detecting α-mannosidase activity in urogenital tract specimens.

BACKGROUND: Chlamydia trachomatis may cause multiple different urogenital tract disorders, but current non-culture assays for rapid screening of C. trachomatis typically use immunochromatography-based methods. We established another new rapid non-culture method for detection of C. trachomatis based on the measurement of α-mannosidase enzymatic activity in urogenital tract specimens. METHOD: To evaluate the performance of this method, α-mannosidase activities of C. trachomatis serotype D strain 、 and 29 standard strains related to clinical urogenital pathogens were investigated. Furthermore, 553 urogenital tract specimens were used for clinical assays via cell culture method and ligase chain reaction method (LCR), adopting an expanded gold standard. RESULTS: Only C. trachomatis was positive for α-mannosidase activity among different types of microbes tested in the research. When prostate fluid specimens, which have some interfering activity, were excluded, the sensitivity and specificity of the enzymatic method were 91.8% (78/85) and 98.3% (409/416), respectively. There were no significant differences (P > 0.05). CONCLUSIONS: These results showed that α-mannosidase activity could be utilised as a screening marker of C. trachomatis infection.

[Construction of prokaryotic expression vector, expression and purification of ginseng Cu/Zn superoxide dismutase].

The total RNA was extracted from ginseng leaves of Panax ginseng. The Cu/Zn-SOD gene was amplified via RT-PCR and the pET-28(a)-Cu/Zn-SOD expression vector was constructed. The pET-28 (a)-Cu/Zn-SOD recombinant plasmid was transformed into Escherichia coli BL21 (DE3) competent cells and was induced by IPTG in order to select optimal induction of expression conditions. The target protein was purified by the nickel ions (Ni ) affinity chromatography and the target protein enzyme activity was determinated by the xanthine oxidase method. The similarity of the Cu/Zn-SOD gene sequences and the Cu/Zn-SOD gene sequences of Korean ginseng in NCBI was 99. 00%. The target protein expression level was about 44.42%, and the molecular weight was 16.30 kDa after the pET-28(a)-Cu/Zn-SOD recombinants were induced by IPTG. The purified Cu/Zn-SOD protease activity reached 10,596.69 U x mg(-1). The P. ginseng pET-28(a)-Cu/Zn-SOD prokaryotic expression vector was built by the method of molecular biology, which provided the foundation for studying the Cu/Zn-SOD biology function.

Controlled Desiccation of Preprinted Hydrogel Scaffolds Toward Complex 3D Microarchitectures.

Additive manufacturing (AM) is the key to creating a wide variety of 3D structures with unique and programmable functionalities. Direct ink writing is one of the widely used AM technologies with numerous printable materials. However, the extrude-based method is limited by low fabrication resolution, which is confined to printing macrostructures. Herein, a new AM strategy is reported, using a low-cost extrusion 3D printer, to create 3D microarchitectures at the macroscopic level through controlled desiccation of preprinted hydrogel scaffolds followed by infilling objective components. A printable hydrogel with a high-water content ensures maximum shrinkage (≈99.5% in volume) of the printed scaffolds to achieve high resolution. Stable covalent cross-linking and a suitable drying rate enable uniform shrinkage of the scaffolds to retain their original architectures. Particularly, this method can be adapted to produce liquid-metal-based 3D circuits and nanocomposite-based microrobots, indicating its capability to fabricate functional and complex 3D architectures with micron-level resolution from different material systems.

Patient-related factors related to prolonged preparation-to-colonoscopy interval and insufficient purgative intake before colonoscopy: A post-hoc observational study.

OBJECTIVES: Prolonged preparation-to-colonoscopy (PC) interval and insufficient purgative intake (PI) are two important indicators for quality of bowel preparation for colonoscopy. We aimed to investigate patient-related factors associated with increased PC interval or insufficient PI. METHODS: The post-hoc regression analyses were performed using the data from two prospective studies (NCT04434625 and NCT04101097). Patients receiving reinforced instructions for bowel preparation were recruited. The co-primary outcomes included prolonged PC interval or insufficient PI. RESULTS: Altogether 1806 patients from five endoscopic centers underwent bowel preparation from September 2019 to March 2021. The cut-off values were 6 h for PC interval and 80% for PI. In all, 116 (6.4%) and 73 (4.0%) presented an extended PC interval and insufficient PI, respectively. Multivariate logistic regression analysis showed that a low education level was significantly associated with PC interval ≥6 h. Female sex, body mass index (BMI), and coronary artery disease (CAD) were found to be significantly correlated with insufficient PI in univariate analysis, while multivariate analysis demonstrated BMI <20 kg/m2 (odds ratio [OR] 4.14, 95% confidence interval [CI] 1.92-8.94, P < 0.001) and 20-25 kg/m2 (OR 2.23, 95% CI 1.33-3.73, P = 0.002) and CAD (OR 3.23, 95% CI 1.22-8.53, P = 0.018) were identified as independent risk factors for PI <80%. CONCLUSIONS: In spite of reinforced education, a number of patients did not follow the instructions for bowel preparation. The factors for a prolonged PC interval did not overlap with those for insufficient PI. Individualized interference may be considered in different subpopulations.

Scalable Manufacturing of Mechanical Robust Bioinspired Ceramic-Resin Composites with Locally Tunable Heterogeneous Structures.

Lightweight structural materials with a unique combination of high stiffness, strength, toughness, and hardness, are highly desired yet challenging to be artificially fabricated. Biological structural materials, on the other hand, ingeniously integrate multiple mutually exclusive mechanical properties together relying on their hierarchically heterogeneous structures bonded with gradient interfaces. Here, a scalable bottom-up approach combining continuous nanofiber-assisted evaporation-induced self-assembly with laminating, pressure-less sintering and resin infiltration is reported to fabricate bioinspired heterogeneous ceramic-resin composites with locally tunable microstructure to fulfill specific properties. A gradient interlayer is introduced to provide a gradual transition between adjacent heterogeneous layers, effectively alleviating their property mismatch. The optimized heterogeneous nacre-like composite, as a demonstration, exhibits an attractive combination of low density (≈2.8 g cm-3 ), high strength (≈292 MPa), toughness (≈6.4 MPa m1/2 ), surface hardness (≈1144 kgf mm-2 ) and impact-resistance, surpassing the overall performance of engineering alumina. This material-independent approach paves the way for designing advanced bioinspired heterogeneous materials for diverse structural and functional applications.

Melatonin alleviates oxidative stress-induced injury to nucleus pulposus-derived mesenchymal stem cells through activating PI3K/Akt pathway.

Background: The changes in the microenvironment of degenerative intervertebral discs cause oxidative stress injury and excessive apoptosis of intervertebral disc endogenous stem cells. The purpose of this study was to explore the possible mechanism of the protective effect of melatonin on oxidative stress injury in NPMSCs induced by H2O2. Methods: The Cell Counting Kit-8 assay was used to evaluate the cytotoxicity of hydrogen peroxide and the protective effects of melatonin. ROS content was detected by 2'7'-dichlorofluorescin diacetate (DCFH-DA). Mitochondrial membrane potential (MMP) was detected by the JC-1assay. Transferase mediated d-UTP Nick end labeling (TUNEL) and Annexin V/PI double staining were used to determine the apoptosis rate. Additionally, apoptosis-associated proteins and PI3K/Akt signaling pathway-related proteins were evaluated by immunofluorescence, immunoblotting and PCR. ECMs were evaluated by RT‒PCR and immunofluorescence. In vivo, X-ray, Magnetic resonance imaging (MRI) and Histological analyses were used to evaluate the protective effect of melatonin. Results: Melatonin had an obvious protective effect on NPMSCs treated with 0-10 µM melatonin for 24 h. In addition, melatonin also had obvious protective effects on mitochondrial dysfunction, decreased membrane potential and cell senescence induced by H2O2. More importantly, melatonin could significantly reduce the apoptosis of nucleus pulposus mesenchymal stem cells induced by H2O2 by regulating the expression of apoptosis-related proteins and decreasing the rate of apoptosis. After treatment with melatonin, the PI3K/Akt pathway was significantly activated in nucleus pulposus mesenchymal stem cells, while the protective effect was significantly weakened after PI3K-IN-1 treatment. In vivo, the results of X-ray, MRI and histological analyses showed that therapy with melatonin could partially reduce the degree of intervertebral disc degeneration. Conclusion: Our research demonstrated that melatonin can effectively alleviate the excessive apoptosis and mitochondrial dysfunction of nucleus pulposus mesenchymal stem cells induced by oxidative stress via the PI3K/Akt pathway, which provides a novel idea for the therapy of intervertebral disc degeneration. The translational potential of this article: This study indicates that melatonin can effectively alleviate the excessive apoptosis and mitochondrial dysfunction of NPMSCs through activating the PI3K/Akt pathway. Melatonin might serve as a promising candidate for the prevention and treatment of Intervertebral disc degeneration disease (IVDD) in the future.

Polyhydroxyalkanoates: the natural biopolyester for future medical innovations.

Polyhydroxyalkanoates (PHAs) are a family of natural microbial biopolyesters with the same basic chemical structure and diverse side chain groups. Based on their excellent biodegradability, biocompatibility, thermoplastic properties and diversity, PHAs are highly promising medical biomaterials and elements of medical devices for applications in tissue engineering and drug delivery. However, due to the high cost of biotechnological production, most PHAs have yet to be applied in the clinic and have only been studied at laboratory scale. This review focuses on the biosynthesis, diversity, physical properties, biodegradability and biosafety of PHAs. We also discuss optimization strategies for improved microbial production of commercial PHAs via novel synthetic biology tools. Moreover, we also systematically summarize various medical devices based on PHAs and related design approaches for medical applications, including tissue repair and drug delivery. The main degradation product of PHAs, 3-hydroxybutyrate (3HB), is recognized as a new functional molecule for cancer therapy and immune regulation. Although PHAs still account for only a small percentage of medical polymers, up-and-coming novel medical PHA devices will enter the clinical translation stage in the next few years.

Mechanically robust bamboo node and its hierarchically fibrous structural design.

Although short bamboo nodes function in mechanical support and fluid exchange for bamboo survival, their structures are not fully understood compared to unidirectional fibrous internodes. Here, we identify the spatial heterostructure of the bamboo node via multiscale imaging strategies and investigate its mechanical properties by multimodal mechanical tests. We find three kinds of hierarchical fiber reinforcement schemes that originate from the bamboo node, including spatially tightened interlocking, triaxial interconnected scaffolding and isotropic intertwining. These reinforcement schemes, built on porous vascular bundles, microfibers and more-refined twist-aligned nanofibers, govern the structural stability of the bamboo via hierarchical toughening. In addition, the spatial liquid transport associated with these multiscale fibers within the bamboo node is experimentally verified, which gives perceptible evidence for life-indispensable multidirectional fluid exchange. The functional integration of mechanical reinforcement and liquid transport reflects the fact that the bamboo node has opted for elaborate structural optimization rather than ingredient richness. This study will advance our understanding of biological materials and provide insight into the design of fiber-reinforced structures and biomass utilization.