Nutritional support during the first week for infants with bronchopulmonary dysplasia and respiratory distress: a multicenter cohort study in China.

BACKGROUND: Bronchopulmonary dysplasia (BPD) is a major complication affecting the survival rate and long-term outcomes of preterm infants. A large, prospective, multicenter cohort study was conducted to evaluate early nutritional support during the first week of life for preterm infants with a gestational age < 32 weeks and to verify nutritional risk factors related to BPD development. METHODS: A prospective multicenter cohort study of very preterm infants was conducted in 40 tertiary neonatal intensive care units across mainland China between January 1, 2020, and December 31, 2021. Preterm infants who were born at a gestational age < 32 weeks, < 72 h after birth and had a respiratory score > 4 were enrolled. Antenatal and postnatal information focusing on nutritional parameters was collected through medical systems. Statistical analyses were also performed to identify BPD risk factors. RESULTS: The primary outcomes were BPD and severity at 36 weeks postmenstrual age. A total of 1410 preterm infants were enrolled in this study. After applying the exclusion criteria, the remaining 1286 infants were included in this analysis; 614 (47.7%) infants were in the BPD group, and 672 (52.3%) were in the non-BPD group. In multivariate logistic regression model, the following six factors were identified of BPD: birth weight (OR 0.99, 95% CI 0.99-0.99; p = 0.039), day of full enteral nutrition (OR 1.03, 95% CI 1.02-1.04; p < 0.001), parenteral protein > 3.5 g/kg/d during the first week (OR 1.65, 95% CI 1.25-2.17; p < 0.001), feeding type (formula: OR 3.48, 95% CI 2.21-5.49; p < 0.001, mixed feed: OR 1.92, 95% CI 1.36-2.70; p < 0.001; breast milk as reference), hsPDA (OR 1.98, 95% CI 1.44-2.73; p < 0.001), and EUGR ats 36 weeks (OR 1.40, 95% CI 1.02-1.91; p = 0.035). CONCLUSIONS: A longer duration to achieve full enteral nutrition in very preterm infants was associated with increased BPD development. Breastfeeding was demonstrated to have a protective effect against BPD. Early and rapidly progressive enteral nutrition and breastfeeding should be promoted in very preterm infants. TRIAL REGISTRATION: The trial was registered in the Chinese Clinical Trial Registry (No. ChiCTR2000030125 on 24/02/2020) and in www.ncrcch.org (No. ISRCTN84167642 on 25/02/2020).

Establishment and characterization of a golden pompano (Trachinotus blochii) fin cell line for applications in marine fish pathogen immunology.

Pompano fishes have been widely farmed worldwide. As a representative commercial marine species of the Carangidae family, the golden pompano (Trachinotus blochii) has gained significant popularity in China and worldwide. However, because of rapid growth and high-density aquaculture, the golden pompano has become seriously threatened by various diseases. Cell lines are the most cost-effective resource for in vitro studies and are widely used for physiological and pathological research owing to their accessibility and convenience. In this study, we established a novel immortal cell line, GPF (Golden pompano fin cells). GPF has been passaged over 69 generations for 10 months. The morphology, adhesion and extension processes of GPF were evaluated using light and electron microscopy. GPF cells were passaged every 3 days with L-15 containing 20% fetal bovine serum (FBS) at 1:3. The optimum conditions for GPF growth were 28 °C and a 20% FBS concentration. DNA sequencing of 18S rRNA and mitochondrial 16S rRNA confirmed that GPF was derived from the golden pompano. Chromosomal analysis revealed that the number pattern of GPF was 48 chromosomes. Transfection experiments demonstrated that GPF could be utilized to express foreign genes. Furthermore, heavy metals (Cd, Cu, and Fe) exhibited dose-dependent cytotoxicity against GPF. After polyinosinic-polycytidylic acid (poly I:C) treatment, transcription of the retinoic acid-inducible gene I-like receptor (RLR) pathway genes, including mda5, mita, tbk1, irf3, and irf7 increased, inducing the expression of interferon (IFN) and anti-viral proteins in GPF cells. In addition, lipopolysaccharide (LPS) stimulation up-regulated the expression of inflammation-related factors, including myd88, irak1, nfκb, il1ß, il6, and cxcl10 expression. To the best of our knowledge, this is the first study on the immune response signaling pathways of the golden pompano using an established fin cell line. In this study, we describe a preliminary investigation of the GPF cell line immune response to poly I:C and LPS, and provide a more rapid and efficient experimental material for research on marine fish immunology.

Neural Stem Cells Transplanted into Rhesus Monkey Cortical Traumatic Brain Injury Can Survive and Differentiate into Neurons.

Cortical traumatic brain injury (TBI) is a major cause of cognitive impairment accompanied by motor and behavioral deficits, and there is no effective treatment strategy in the clinic. Cell transplantation is a promising therapeutic strategy, and it is necessary to verify the survival and differentiation of cells after transplantation in large animal models like rhesus monkeys. In this study, we transplanted neural stem cells (NSCs) and simultaneously injected basic fibroblast growth factor/epidermal growth factor (bFGF/EGF) into the cortex (visual and sensory cortices) of rhesus monkeys with superficial TBI. The results showed that the transplanted NSCs did not enter the cerebrospinal fluid (CSF) and were confined to the transplantation site for at least one year. The transplanted NSCs differentiated into mature neurons that formed synaptic connections with host neurons, but glial scar formation between the graft and the host tissue did not occur. This study is the first to explore the repairing effect of transplanting NSCs into the superficial cerebral cortex of rhesus monkeys after TBI, and the results show the ability of NSCs to survive long-term and differentiate into neurons, demonstrating the potential of NSC transplantation for cortical TBI.

Clinical effect of different concentrations of ropivacaine in the labor analgesia of dural puncture epidural technique for obese puerperae.

BACKGROUND: This study was performed to analyze the clinical effect of different concentrations of ropivacaine in the labor analgesia of the dural puncture epidural (DPE) technique for obese puerperae. METHODS: One hundred and fifty first-term obese women who received vaginal delivery and required labor analgesia in our hospital were selected prospectively for this study, and divided into groups A, B, and C. The three groups of puerpera were given epidurals with different concentrations of ropivacaine (0.075%, 0.10%, and 0.125%) with sufentanil (0.5 µg/ml) for the labor analgesia regimen. The visual analog scale (VAS), Ramsay scale, and Bromage scale of puerperae before analgesia and at different time points after anesthesia, and analgesic onset time, analgesia time, first PCEA time, PCEA pressing time, ropivacaine consumption, labor time, maternal blood pressure and heart rate, maternal adverse reactions, blood gas analysis in the neonatal umbilical artery, and Apgar score were observed. RESULTS: The analgesia onset time, PCEA pressing time, and ropivacaine consumption in group C were lower and the analgesia time and the first PCEA time were longer than those in groups A and B. At T1-T3 and T5, VAS scores of group A were higher than those in groups B and C, Ramsay score of group A was lower than that of groups B and C at T2-T3, and Bromage score of group C at any time point was higher than other two groups. The time of the second stage of labor in groups B and C was longer than that in group A, which in group C was longer than that in group B. Compared with groups A and C, the blood pressure and heart rate of puerperae in group B were closer to normal values. Three different concentrations of ropivacaine had no significant effect on the umbilical artery blood gas analysis indices and Apgar scores at 1st minute and 5th minute in neonates. The incidence of maternal adverse reactions in group C was lower than those in groups A and B. CONCLUSION: 0.1% ropivacaine combined with 0.5 µg/ml sufentanil through DPE technique has good analgesic efficacy and few adverse effects in obese puerperae.

Identification of a potent and specific retinoic acid-inducible gene 1 pathway activator as a Hepatitis B Virus antiviral through a novel cell-based reporter assay.

Chronic Hepatitis B Virus (HBV) infection remains a global burden. To identify small molecule RIG-I agonists as antivirals against HBV, we developed an HBV-pgRNA-based interferon-ß (IFN-ß) luciferase reporter assay with high level of assay sensitivity, specificity and robustness. Through HTS screening, lead compound (JJ#1) was identified to activate RIG-I signaling pathway by inducing TBK1 phosphorylation. Knockdown experiments demonstrated that JJ#1-induced retinoic acid-inducible gene 1 (RIG-I) signaling pathway activation was MAVS-dependent. Furthermore, JJ#1 exhibited HBV antiviral potency in HBV-infected cell models by reducing HBV DNA and antigens (HBsAg and HBeAg).

Elemene Antitumor Drugs Development Based on "Molecular Compatibility Theory" and Clinical Application: A Retrospective and Prospective Outlook.

Elemene, derived from Curcuma wenyujin, one of the "8 famous genuine medicinal materials of Zhejiang province," exhibits remarkable antitumor activity. It has gained wide recognition in clinical practice for effectiveness on tumors. Dr. XIE Tian, introduced the innovative concept of "molecular compatibility theory" by combining Chinese medicine principles, specifically the "monarch, minister, assistant, and envoy" theory, with modern biomedical technology. This groundbreaking approach, along with a systematic analysis of Chinese medicine and modern biomedical knowledge, led to the development of elemene nanoliposome formulations. These novel formulations offer numerous advantages, including low toxicity, well-defined composition, synergistic effects on multiple targets, and excellent biocompatibility. Following the principles of the "molecular compatibility theory", further exploration of cancer treatment strategies and methods based on elemene was undertaken. This comprehensive review consolidates the current understanding of elemene's potential antitumor mechanisms, recent clinical investigations, advancements in drug delivery systems, and structural modifications. The ultimate goal of this review is to establish a solid theoretical foundation for researchers, empowering them to develop more effective antitumor drugs based on the principles of "molecular compatibility theory".

Low-Entropy Hydration Shells at the Spike RBD's Binding Site May Reveal the Contagiousness of SARS-CoV-2 Variants.

The infectivity of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is primarily determined by the binding affinity between the receptor-binding domain (RBD) of the spike protein and the angiotensin-converting enzyme 2 (ACE2) receptor. Here, through screening off pseudo hydrophilic groups on protein surfaces, the distribution of low-entropy regions on hydration shells of the ACE2 receptor and the RBDs of multiple SARS-CoV-2 variants was demonstrated. Shape matching between the low-entropy hydration shells of multiple SARS-CoV-2 variants and the ACE2 receptor has been identified as a mechanism that drives hydrophobic attraction between the RBDs and the ACE2 receptor, which estimates the binding affinity. Low-entropy regions of the hydration shells, which play important roles in determining the binding of other viruses and their receptors, are demonstrated. The RBD-ACE2 binding is thus found to be guided by hydrophobic collapse between the shape-matched low-entropy regions of the hydration shells of the proteins. A measure of the low-entropy status of the hydration shells can be estimated by calculating genuine hydrophilic groups within the binding sites. An important indicator of the contagiousness of SARS-CoV-2 variants is the low-entropy level of its hydration shells at the spike protein binding site.

Risk factors for bronchopulmonary dysplasia infants with respiratory score greater than four: a multi-center, prospective, longitudinal cohort study in China.

Bronchopulmonary dysplasia (BPD) is the most common complication of prematurity involving both pre- and post-natal factors. A large, prospective, longitudinal cohort study was conducted to determine whether inflammation-related factors are associated with an increased risk of BPD in preterm infants who were born at a gestational age < 32 weeks, < 72 h after birth and respiratory score > 4. The study included infants from 25 participating hospitals in China between March 1, 2020 and March 31, 2022. The primary outcomes were BPD and severity of BPD at 36 weeks post-menstrual age. A total of 1362 preterm infants were enrolled in the study. After exclusion criteria, the remaining 1088 infants were included in this analysis, of whom, 588 (54.0%) infants were in the BPD group and 500 (46.0%) were in the non-BPD group. In the BPD III model, the following six factors were identified: birth weight (OR 0.175, 95% CI 0.060-0.512; p = 0.001), surfactant treatment (OR 8.052, 95% CI 2.658-24.399; p < 0.001), mean airway pressure (MAP) ≥ 12 cm H2O (OR 3.338, 95% CI 1.656-6.728; p = 0.001), late-onset sepsis (LOS) (OR 2.911, 95% CI 1.514-5.599; p = 0.001), ventilator-associated pneumonia (VAP) (OR 18.236, 95% CI 4.700-70.756; p < 0.001) and necrotizing enterocolitis (NEC) (OR 2.725, 95% CI 1.182-6.281; p = 0.019). Premature infants remained at high risk of BPD and with regional variation. We found that post-natal inflammation-related risk factors were associated with an increased risk of severe BPD, including LOS, VAP, NEC, MAP ≥ 12 cm H2O and use of surfactant.

[Risk factors and prognosis of hypotension within 72 hours after birth in extremely preterm infants]. / è¶ æ—©äº§å„¿ç”ŸåŽ72 hå† ä½Žè¡€åŽ‹å‘ç”Ÿçš„å±é™©å› ç´ åŠé¢„åŽåˆ†æž.

OBJECTIVES: To investigate the risk factors and prognosis of hypotension within 72 hours after birth in extremely preterm infants. METHODS: A retrospective analysis was conducted on clinical data of extremely preterm infants admitted to the Children's Hospital of Zhejiang University School of Medicine from January 2019 to April 2022. Based on the presence of hypotension within 72 hours after birth, the eligible infants were divided into a hypotension group (41 cases) and a normotension group (82 cases). The clinical characteristics, echocardiographic parameters within 72 hours after birth, and early complications were compared between the two groups. Multivariate logistic regression analysis was used to explore the risk factors for hypotension within 72 hours after birth, and receiver operating characteristic curve analysis was performed to evaluate the predictive value of relevant indicators for the occurrence of hypotension within 72 hours after birth in the preterm infants. RESULTS: The proportion of infants who required medication or surgical closure of patent ductus arteriosus (PDA), the proportions of infants with intraventricular hemorrhage ≥ grade III and severe pulmonary hemorrhage, and the mortality rate within 7 days in the hypotension group were significantly higher than those in the normotension group (P<0.05). Multivariate logistic regression analysis showed that lower birth weight, larger PDA diameter, and hemodynamically significant PDA were risk factors for the occurrence of hypotension within 72 hours after birth in extremely preterm infants (P<0.05). The receiver operating characteristic curve analysis showed that the combination of birth weight, PDA diameter, and hemodynamically significant PDA had an area under the curve of 0.873 (95%CI: 0.802-0.944, P<0.05) for predicting hypotension within 72 hours after birth, with a sensitivity of 73.2% and specificity of 91.5%. CONCLUSIONS: Hypotension within 72 hours after birth is closely related to birth weight and PDA, and increases the risk of early severe complications and mortality in extremely preterm infants.

Clinical study on laparoscopic minimally invasive surgery and transumbilical single-port laparoscopic surgery in the treatment of benign ovarian tumours and its influence on ovarian functions.

Objective: The objective of this study was to explore the influence of traditional laparoscopic surgery and transumbilical single-port laparoscopic surgery on ovarian function in patients with benign ovarian tumours. Materials and Methods: Forty-four patients with benign ovarian tumours who were treated in our hospital from January 2020 to June 2021 were selected and randomly divided into two groups, with 22 cases in each group according to random number table. The conventional group was treated with conventional laparoscopic surgery, while the modified group was treated with transumbilical single-port laparoscopic surgery. The measurement method was t-test, and the enumeration method was two tests. The clinical operation-related indicators, ovarian function (follicle-stimulating hormone, E2 and luteinising hormone), complication incidence, Visual Analogue Scale (VAS) and landscaping satisfaction scores of the two groups were compared. Results: There were no significant differences in complications and operation duration between the two groups (P > 0.05). After treatment, the ovarian function indexes and beautification satisfaction scores of the modified group were significantly superior to those of the conventional group (P < 0.05). Besides, the intraoperative bleeding volume, post-operative exhaust time, hospital stay and three-dimensional VAS scores on day 1 and day 3 after surgery of the modified group were lower than those of the conventional group (P < 0.05). Conclusion: Transumbilical single-port laparoscopic surgery for benign ovarian tumours has a significant clinical effect, which can effectively reduce bleeding during the operation, improve ovarian function, relieve surgical pain, promote rapid post-operative recovery and improve patients' satisfaction with landscaping. It is worthy of clinical application.

Transcriptome analysis reveals candidate miRNAs involved in skin color differentiation of juvenile Plectropomus leopardus in response to different background colors.

Red skin color in Plectropomus leopardus is important to its ornamental and economic value. However, the color of P. leopardus can change during the rearing process, darkening and turning black due to the influence of environmental background color. The underlying molecular mechanisms that regulate this phenomenon remain unclear. MicroRNAs (miRNAs) are endogenous, small non-coding RNAs that play important roles in numerous biological processes, such as skin differentiation and color formation in many animals. Therefore, we performed miRNA sequencing of P. leopardus skin before (initial) and after rearing with three different background colors (white, black, and blue) using Illumina sequencing to identify candidate miRNAs that may contribute to skin color differentiation. In total, 154,271,376 clean reads were obtained, with over 92 % of them successfully mapped to the P. leopardus reference genome. The miRNA length distributions of all samples displayed peaks around a typical length of 22 nt. Within these sequences, 243 known and 287 novel miRNAs were identified. A total of 65 significantly differentially expressed miRNAs (DEMs) were identified (P < 0.05), including 40 known DEMs and 25 novel DEMs. These DEMs included novel_561, miR-141-3p, and miR-129-5p, whose target genes were primarily associated with pigmentation related processes, including tyrosine metabolism, melanogenesis, and the Wnt signaling pathway. These findings shed light on the potential roles of miRNAs in the darkening of skin color in P. leopardus, thus enhancing our understanding of the molecular mechanisms involved in skin pigmentation differentiation in this species.

Thermal Conductivity of 3C/4H-SiC Nanowires by Molecular Dynamics Simulation.

Silicon carbide (SiC) is a promising material for thermoelectric power generation. The characterization of thermal transport properties is essential to understanding their applications in thermoelectric devices. The existence of stacking faults, which originate from the "wrong" stacking sequences of Si-C bilayers, is a general feature of SiC. However, the effects of stacking faults on the thermal properties of SiC are not well understood. In this study, we evaluated the accuracy of Tersoff, MEAM, and GW potentials in describing the thermal transport of SiC. Additionally, the thermal conductivity of 3C/4H-SiC nanowires was investigated using non-equilibrium molecular dynamics simulations (NEMD). Our results show that thermal conductivity exhibits an increase and then saturation as the total lengths of the 3C/4H-SiC nanowires vary from 23.9 nm to 95.6 nm, showing the size effect of molecular dynamics simulations of the thermal conductivity. There is a minimum thermal conductivity, as a function of uniform period length, of the 3C/4H-SiC nanowires. However, the thermal conductivities of nanowires weakly depend on the gradient period lengths and the ratio of 3C/4H. Additionally, the thermal conductivity of 3C/4H-SiC nanowires decreases continuously from compressive strain to tensile strain. The reduction in thermal conductivity suggests that 3C/4H-SiC nanowires have potential applications in advanced thermoelectric devices. Our study provides insights into the thermal transport properties of SiC nanowires and can guide the development of SiC-based thermoelectric materials.

Dermatosis Neglecta Based on Exanthematous Drug Eruption Following Head Trauma: A Case Report and Literature Review.

Dermatosis neglecta (DN) is a rare psychogenic dermatosis. To our knowledge, this is the first reported case of DN based on exanthematous drug eruption. We report a 68-year-old Chinese male patient who presented with thick, yellowish-brown crusting on his face and scalp and scaly skin for 6 days. Dermoscopy revealed diffusely distributed yellow-green serescrust-like plaques with different sizes and uneven thickness on a red background, and some demonstrated dot or globular hemorrhages. We considered DN and exanthematous drug eruptions based on the combination of the clinical medication and the history before the rash.

The muscle nutritional components analysis of golden pompano (Trachinotus blochii) in different mariculture area, growth stages, and genders.

Golden pompano (Trachinotus blochii) is an economically important fish which exhibits sexual size dimorphism and is widely cultivated in the southern seas of China. To evaluate the nutritional composition of T. blochii of different mariculture areas, growth stages, and genders, the moisture, ash, amino acids, and fatty acids in the muscle were measured using national standard biochemical assay. The analysis found 16 kinds of amino acids in the muscle of T. blochii. The EAA contents of fish from Guangdong (GD) and Guangxi (GX) were significantly lower than those of Hainan (HN) and Fujian (FJ) (p < 0.05). The unsaturated fatty acids were higher in T. blochii cultured in HN and FJ (p < 0.05). Within the same sea area, the contents of TAA, EAA, DAA, and PUFA increased with growth in T. blochii, but the differences were not significant (p > 0.05). EAA/TAA and EAA/NEAA conformed to the ideal FAO/WHO model. The AAS, CS, and EAAI scores of amino acids within groups gradually increased with growth. The TAA, EAA and PUFA contents in females were higher than in males (p > 0.05). The slightly higher amounts of amino acids and fatty acids in female T. blochii indicated females had higher nutritional value. In conclusion, the HN and FJ groups, the later growth stages, and the female T. blochii had generally higher nutritional values than their respective counterparts. These results provide fundamental data supporting all-female T. blochii breeding and culture, and optimized marketing body size.

Bioinformatics and Systems Biology Approach to Identify the Pathogenetic Link Between Psoriasis and Cardiovascular Disease.

Objective: This study aimed to identify hub genes and common pathways shared between psoriasis and cardiovascular disease (CVD) using bioinformatics analysis and predict the transcription factors (TFs) of hub genes. Methods: GSE133555 data from the Gene Expression Omnibus (GEO) database were used to identify differentially expressed genes (DEGs) between involved and uninvolved skin lesions in psoriasis, employing the limma package in R. Additionally, CVD-related genes were obtained from the GeneCards database. The intersection of DEGs and CVD-related genes yielded CVD-DEGs. Gene Ontology and signaling pathway analyses were performed using the clusterProfiler package in R. Hub genes were identified by intersecting six algorithms in the CytoHubba plugin of Cytoscape. To identify potential biomarkers, the GSE14905 dataset was subjected to receiver operating characteristic analysis, resulting in the identification of eight central hub genes. Finally, the NetworkAnalyst web tool was used to identify the TFs of the eight hub genes. Results: We identified 92 significant DEGs out of 1825 CVD-related genes in psoriasis obtained from the GSE13355 and GeneCard data. Functional enrichment analysis revealed the involvement of these genes in various signaling pathways, including the interleukin-17 signaling, tumor necrosis factor signaling, lipid and atherosclerosis, chemokine signaling, and cytokine signaling pathways in the immune system. The eight hub genes identified included interleukin-1 beta, C-X-C motif chemokine ligand 8, signal transducer and activator of transcription 3, C-C motif chemokine ligand 2, arginase 1, C-X-C motif chemokine receptor 4, cyclin D1, and matrix metallopeptidase 9, with forkhead box C1 also identified as an associated TF of these genes. These hub genes and TF may act as key regulators in the context of CVD. Conclusion: This study identified several hub genes and signaling pathways associated with both CVD and psoriasis. These findings lay the groundwork for potential therapeutic interventions for patients with psoriasis affected by CVD.

Weighted correlation network analysis of the genes in the eyes of juvenile Plectropomus leopardus provide novel insights into the molecular mechanisms of the adaptation to the background color.

Plectropomus leopardus is a valuable marine fish whose skin color is strongly affected by the background color. However, the influence of the visual sense on the skin color variation of P. leopardus remains unknown. In the present study, transcriptome analysis was used to examine the visual response mechanism under different background colors. Paraffin sections of the eyes showed that the background color caused morphological changes in the pigment cells (PCs) and outer nuclear layer (ONL) and the darkening of the iris color. The transcriptome analysis results indicated that the gene expressions in the eyes of P. leopardus were significantly different for different background colors. We identified 4845, 3069, 5874, and 6309 differentially expressed genes (DEGs) in the pairwise comparisons of white vs. initial, blue vs. initial, red vs. initial, and black vs. initial groups, respectively. Some hub genes and key pathways regulating the adaptive mechanism of P. leopardus's eyes to the background color were identified, i.e., the JAK-STAT, mTOR, and Ras signaling pathways, and the ndufb7, slc6a13, and novel.3553 gene. This adaptation was achieved through the synthesis of stress proteins and energy balance supply mediated by hub genes and key pathways. In addition, the phenylalanine metabolism, tyrosine metabolism, and actin cytoskeleton-related processes or pathways and genes were responsible for iris and skin color adaptation. In summary, we inferred that stress protein synthesis, phenylalanine metabolism, and energy homeostasis were critical stress pathways for P. leopardus to adapt its skin color to the environment. These new findings indicate that the P. leopardus skin color variation may have been caused by the environmental adaption of the eyes. The results provide new insights into the molecular mechanisms underlying the skin color adaptation of P. leopardus.

Superhardness in nanotwinned boron carbide: a molecular dynamics study.

Boron carbide ceramics are often considered ideal materials for lightweight bulletproof armor, but their anomalous brittle failure at hypervelocity impact limits their use. Recent experiments have reported that nanotwins are ubiquitous in boron carbide and that nanotwinned samples are harder than the twin-free boron carbide, but although the strengthening effect of nanotwins on metals and alloys is well-established, their role in boron carbide ceramics is not well understood. In this study, we used classical molecular dynamics simulations to investigate how nanoscale twins affect the mechanical properties of boron carbide ceramics. Our classical molecular dynamics results show that introducing nanotwins in boron carbide can increase the shear strength limit by 19.72%, reduce the number of amorphized atoms, and narrow the width of the amorphous shear band. Under indentation load, nanotwins can also increase the compressive shear strength limit of boron carbide by 15.97% and change the crystal formation direction and region of the amorphous shear band. These findings suggest that twin boundaries can hinder the expansion of the amorphous shear band and provide a new design idea for improving the impact resistance of boron carbide ceramics and avoiding their abnormal brittle failure.

Spatial Layouts of Low-Entropy Hydration Shells Guide Protein Binding.

Protein-protein binding enables orderly biological self-organization and is therefore considered a miracle of nature. Protein‒protein binding is driven by electrostatic forces, hydrogen bonding, van der Waals force, and hydrophobic interactions. Among these physical forces, only hydrophobic interactions can be considered long-range intermolecular attractions between proteins due to the electrostatic shielding of surrounding water molecules. Low-entropy hydration shells around proteins drive hydrophobic attraction among them that essentially coordinate protein‒protein binding. Here, an innovative method is developed for identifying low-entropy regions of hydration shells of proteins by screening off pseudohydrophilic groups on protein surfaces and revealing that large low-entropy regions of the hydration shells typically cover the binding sites of individual proteins. According to an analysis of determined protein complex structures, shape matching between a large low-entropy hydration shell region of a protein and that of its partner at the binding sites is revealed as a universal law. Protein‒protein binding is thus found to be mainly guided by hydrophobic collapse between the shape-matched low-entropy hydration shells that is verified by bioinformatics analyses of hundreds of structures of protein complexes, which cover four test systems. A simple algorithm is proposed to accurately predict protein binding sites.

Modules in robust but low-efficiency phyllosphere fungal networks drive saponin accumulation in leaves of different Panax species.

BACKGROUND: The phyllosphere mycobiome plays a crucial role in plant fitness and ecosystem functions. The complex microbial ecological networks (MEN) formed by these fungi remain poorly understood, particularly with regard to their organization strategy and their contributions to plant secondary metabolites such as saponin. RESULTS: In this study, we constructed six MENs from leaf epiphytic and endophytic mycobiomes of three Panax species distributed in the northeast and southwest ends of mainland China. Hub nodes were absent in these MENs, which were significantly more complex, robust, and less efficient compared to random graphs (P < 0.05), indicating a hub-independent high-robustness strategy to maintain structural homeostasis. The important roles of specific MEN modules in shaping leaf saponin profiles of each Panax species were proved by multiple machine learning algorithms. Positive regulation modules (PRMs) of total saponin content were further identified, which exhibited more deterministic ecological assembly and comprised of highly connected nodes as well as higher proportion of plant-associated fungal guilds compared to other network members, indicating their tight links with host plant. The significant and direct effects (P < 0.05) of PRMs on total saponin accumulation were validated by well-fitted structural equation models (χ2 < 0.3, P > 0.5). Taxonomic analysis revealed that Pleosporales and Chaetothyriales were significantly overrepresented by positive regulation taxa (PRT) of total saponin content (FDR < 0.05). Across PRT identified in three Panax species, Epicoccum and Coniothyrium were conservatively present, while species-specific taxa such as Agaricales were also found, indicating the conservatism and specificity of plant-fungi interactions associated with leaf saponin accumulation in Panax genus. CONCLUSIONS: These findings provide a foundation for understanding mechanisms maintaining the steady state of phyllosphere mycobiome in healthy plant, and offer clues for engineering phyllosphere mycobiome to improve the accumulation of bioactive secondary metabolites on the basis of network modules.

[Research summary of chemical constituents and pharmacological effects of Panax notoginseng and predictive analysis on its Q-markers].

Panax notoginseng contains triterpene saponins, flavonoids, amino acids, polysaccharides, volatile oil and other active components, which have the effects of promoting blood circulation, stopping bleeding, removing blood stasis, etc. This study summarized the herbal research, chemical constituents and main pharmacological activities of P. notoginseng, and based on the theory of Q-markers of traditional Chinese medicine, predicted and analyzed the Q-markers of P. notoginseng from the aspects of plant kinship, efficacy, drug properties, measurability of chemical components, etc. It was found that ginsenosides Rg_1, Re, and Rb_1 with specific content ratio, ginsenosides Rb_2, Rb_3, Rc, Rd, Rh_2, and Rg_3, notoginseng R_1, dencichine and quercetin could be used as potential Q-markers of P. notoginseng, which facilitated the formulation of quality standards reflecting the efficacy of P. notoginseng.