Precisely constructing orbital coupling-modulated iron dinuclear site for enhanced catalytic ozonation performance.

The advancement of atomically precise dinuclear heterogeneous catalysts holds great potential in achieving efficient catalytic ozonation performance and contributes to the understanding of synergy mechanisms during reaction conditions. Herein, we demonstrate a "ship-in-a-bottle and pyrolysis" strategy that utilizes Fe2(CO)9 dinuclear-cluster to precisely construct Fe2 site, consisting of two Fe1-N3 units connected by Fe-Fe bonds and firmly bonded to N-doped carbon. Systematic characterizations and theoretical modeling reveal that the Fe-Fe coordination motif markedly reduced the devotion of the antibonding state in the Fe-O bond because of the strong orbital coupling interaction of dual Fe d-d orbitals. This facilitates O-O covalent bond cleavage of O3 and enhances binding strength with reaction intermediates (atomic oxygen species; *O and *OO), thus boosting catalytic ozonation performance. As a result, Fe dinuclear site catalyst exhibits 100% ozonation efficiency for CH3SH elimination, outperforming commercial MnO2 catalysts by 1,200-fold. This research provides insights into the atomic-level structure-activity relationship of ozonation catalysts and extends the use of dinuclear catalysts in catalytic ozonation and beyond.

Comparative and phylogenetic analysis of the complete chloroplast genomes of ten Pittosporum species from East Asia.

Pittosporum (Pittosporaceae) is famous as the ornamental and medical values, which is distributed tropical and subtropical regions of Eastern Hemisphere. The few phylogenetic studies have included samples from the Pacific Island, but the phylogenetic relationships of Asian species has not been studied. Here, the complete chloroplast (cp) genomes of ten Pittosporum species from East Asia were first sequenced and compared with those of the published species of this genus. Our results indicated that cp genomes of these species had a typical and conserved quadripartite structure. 131 genes were identical in order and orientation and no changes of inverted repeat (IR) occurred. However, the comparative analysis of cp genomes suggested that sequence divergence mainly appeared in non-coding or intergenic regions, in which several divergence hotspots were identified. By contrast, protein-coding genes showed the lowest variance under strong purifying selection. Phylogenetic analysis based on the cp genome sequences showed that the tested Pittosporum species were clustered into two major clades, in which the Asian species formed Clade I and the remaining species from Australia and New Zealand formed Clade II with high support values, which was consistent with the results of ITS data with low support values. These results suggested that cp genome is a robust phylogenetic indicator for deep nodes in the phylogeny of Pittosporum. Meanwhile, these results will provide the valuable information to better understand the phylogeny and biogeography of Pittosporum.

Optimization of Carbon-Defect Engineering to Boost Catalytic Ozonation Efficiency of Single Fe─N4 Coordination Motif.

Carbon-defect engineering in single-atom metal-nitrogen-carbon (M─N─C) catalysts by straightforward and robust strategy, enhancing their catalytic activity for volatile organic compounds, and uncovering the carbon vacancy-catalytic activity relationship are meaningful but challenging. In this study, an iron-nitrogen-carbon (Fe─N─C) catalyst is intentionally designed through a carbon-thermal-diffusion strategy, exposing extensively the carbon-defective Fe─N4 sites within a micro-mesoporous carbon matrix. The optimization of Fe─N4 sites results in exceptional catalytic ozonation efficiency, surpassing that of intact Fe─N4 sites and commercial MnO2 by 10 and 312 times, respectively. Theoretical calculations and experimental data demonstrated that carbon-defect engineering induces selective cleavage of C─N bond neighboring the Fe─N4 motif. This induces an increase in non-uniform charges and Fermi density, leading to elevated energy levels at the center of Fe d-band. Compared to the intact atomic configuration, carbon-defective Fe─N4 site is more activated to strengthen the interaction with O3 and weaken the O─O bond, thereby reducing the barriers for highly active surface atomic oxygen (*O/*OO), ultimately achieving efficient oxidation of CH3 SH and its intermediates. This research not only offers a viable approach to enhance the catalytic ozonation activity of M─N─C but also advances the fundamental comprehension of how periphery carbon environment influences the characteristics and efficacy of M─N4 sites.

Advancements in Electrocatalytic Nitrogen Reduction: A Comprehensive Review of Single-Atom Catalysts for Sustainable Ammonia Synthesis.

Electrocatalytic nitrogen reduction technology seamlessly aligns with the principles of environmentally friendly chemical production. In this paper, a comprehensive review of recent advancements in electrocatalytic NH3 synthesis utilizing single-atom catalysts (SACs) is offered. Into the research and applications of three categories of SACs: noble metals (Ru, Au, Rh, Ag), transition metals (Fe, Mo, Cr, Co, Sn, Y, Nb), and nonmetallic catalysts (B) in the context of electrocatalytic ammonia synthesis is delved. In-depth insights into the material preparation methods, single-atom coordination patterns, and the characteristics of the nitrogen reduction reaction (NRR) are provided. The systematic comparison of the nitrogen reduction capabilities of various SAC types offers a comprehensive research framework for their integration into electrocatalytic NRR. Additionally, the challenges, potential solutions, and future prospects of incorporating SACs into electrocatalytic nitrogen reduction endeavors are discussed.

Markov state models elucidate the stability of DNA influenced by the chiral 5S-Tg base.

The static and dynamic structures of DNA duplexes affected by 5S-Tg (Tg, Thymine glycol) epimers were studied using MD simulations and Markov State Models (MSMs) analysis. The results show that the 5S,6S-Tg base caused little perturbation to the helix, and the base-flipping barrier was determined to be 4.4 kcal mol-1 through the use of enhanced sampling meta-eABF calculations, comparable to 5.4 kcal mol-1 of the corresponding thymine flipping. Two conformations with the different hydrogen bond structures between 5S,6R-Tg and A19 were identified in several independent MD trajectories. The 5S,6R-Tg:O6HO6•••N1:A19 hydrogen bond is present in the high-energy conformation displaying a clear helical distortion, and near barrier-free Tg base flipping. The low-energy conformation always maintains Watson-Crick base pairing between 5S,6R-Tg and A19, and 5S-Tg base flipping is accompanied by a small barrier of ca. 2.0 KBT (T = 298 K). The same conformations are observed in the MSMs analysis. Moreover, the transition path and metastable structures of the damaged base flipping are for the first time verified through MSMs analysis. The data clearly show that the epimers have completely different influence on the stability of the DNA duplex, thus implying different enzymatic mechanisms for DNA repair.

Insights into Preparation Methods and Functions of Carbon-Based Solid Acids.

With the growing emphasis on green chemistry and the ecological environment, researchers are increasingly paying attention to greening materials through the use of carbon-based solid acids. The diverse characteristics of carbon-based solid acids can be produced through different preparation conditions and modification methods. This paper presents a comprehensive summary of the current research progress on carbon-based solid acids, encompassing common carbonization methods, such as one-step, two-step, hydrothermal, and template methods. The composition of carbon source material may be the main factor affecting its carbonization method and carbonization temperature. Additionally, acidification types including sulfonating agent, phosphoric acid, heteropoly acid, and nitric acid are explored. Furthermore, the functions of carbon-based solid acids in esterification, hydrolysis, condensation, and alkylation are thoroughly analyzed. This study concludes by addressing the existing drawbacks and outlining potential future development prospects for carbon-based solid acids in the context of their important role in sustainable chemistry and environmental preservation.

Characterization and phylogenetic analyses of ten complete plastomes of Spiraea species.

BACKGROUND: Spiraea is a genus of deciduous shrubs that contains 80-120 species, is mainly distributed in the Northern Hemisphere and has diversified in East Asia. Spiraea species are cultivated as ornamental plants and some are used in traditional herbal medicine. Based on morphological characteristics and genetic markers, phylogenetic classification exhibits low discriminatory power. RESULTS: In present study, we assembled and characterized the chloroplast (cp) genomes of ten Spiraea species and comparatively analysed with five reported cp genomes of this genus. The cp genomes of the fifteen Spiraea species, ranging from 155,904 to 158,637 bp in length, were very conserved and no structural rearrangements occurred. A total of 85 protein-coding genes (PCGs), 37 tRNAs and 8 rRNAs were annotated. We also examined 1,010 simple sequence repeat (SSR) loci, most of which had A/T base preference. Comparative analysis of cp genome demonstrated that single copy and non-coding regions were more divergent than the inverted repeats (IRs) and coding regions and six mutational hotspots were detected. Selection pressure analysis showed that all PCGs were under purifying selection. Phylogenetic analysis based on the complete cp genome data showed that Spiraea formed a monophyletic group and was further divided into two major clades. Infrageneric classification in each clade was supported with a high resolution value. Moreover, the phylogenetic trees based on each individual mutational hotspot segment and their combined dataset also consisted of two major clades, but most of the phylogenetic relationships of interspecies were not well supported. CONCLUSIONS: Although the cp genomes of Spiraea species exhibited high conservation in genome structure, gene content and order, a large number of polymorphism sites and several mutation hotspots were identified in whole cp genomes, which might be sufficiently used as molecular markers to distinguish Spiraea species. Phylogenetic analysis based on the complete cp genome indicated that infrageneric classification in two major clades was supported with high resolution values. Therefore, the cp genome data of the genus Spiraea will be effective in resolving the phylogeny in this genus.

Advances in Mn-Based MOFs and Their Derivatives for High-Performance Supercapacitor.

As the most widely used metal material in supercapacitors, manganese (Mn)-based materials possess the merits of high theoretical capacitance, stable structure as well as environmental friendliness. However, due to poor conductivity and easy accumulation, the practical capacitance of Mn-based materials is far lower than that of theoretical value. Therefore, accurate structural adjustment and controllable strategies are urgently needed to optimize the electrochemical properties of Mn-based materials. Metal-organic frameworks (MOFs) are porous materials with high specific surface area (SSA), tunable pore size, and controllable structure. These features make them attractive as precursors or scaffold for the synthesis of metal-based materials and composites, which are important for electrochemical energy storage applications. Therefore, a timely and comprehensive review on the classification, design, preparation and application of Mn-based MOFs and their derivatives for supercapacitors has been given in this paper. The recent advancement of Mn-based MOFs and their derivatives applied in supercapacitor electrodes are particularly highlighted. Finally, the challenges faced by Mn-MOFs and their derivatives for supercapacitors are summarized, and strategies to further improve their performance are proposed. The aspiration is that this review will serve as a beneficial compass, guiding the logical creation of Mn-based MOFs and their derivatives in the future.

Accelerated Catalytic Ozonation in a Mesoporous Carbon-Supported Atomic Fe-N4 Sites Nanoreactor: Confinement Effect and Resistance to Poisoning.

The design of a micro-/nanoreactor is of great significance for catalytic ozonation, which can achieve effective mass transfer and expose powerful reaction species. Herein, the mesoporous carbon with atomic Fe-N4 sites embedded in the ordered carbon nanochannels (Fe-N4/CMK-3) was synthesized by the hard-template method. Fe-N4/CMK-3 can be employed as nanoreactors with preferred electronic and geometric catalytic microenvironments for the internal catalytic ozonation of CH3SH. During the CH3SH oxidation process, the mass transfer coefficient of the Fe-N4/CMK-3 confined system with sufficient O3 transfer featured a level of at least 1.87 × 10-5, which is 34.6 times that of the Fe-N4/C-Si unconfined system. Detailed experimental studies and theoretical calculations demonstrated that the anchored atomic Fe-N4 sites and nanoconfinement effects regulated the local electronic structure of the catalyst and promoted the activation of O3 molecules to produce atomic oxygen species (AOS) and reactive oxygen species (ROS), eventually achieving efficient oxidation of CH3SH into CO2/SO42-. Benefiting from the high diffusion rate and the augmentation of AOS/ROS, Fe-N4/CMK-3 exhibited an excellent poisoning tolerance, along with high catalytic durability. This contribution provides the proof-of-concept strategy for accelerating catalytic ozonation of sulfur-containing volatile organic compounds (VOCs) by combining confined catalysis and atomic catalysts and can be extended to the purification of other gaseous pollutants.

Grafting of Maleic Anhydride onto Poly(vinylidene fluoride) Using Reactive Extrusion.

Poly(vinylidene fluoride) was grafted with maleic anhydride through reactive extrusion by using diisopropyl benzene peroxide as an initiator and 9-vinyl anthracene as a stabilizer. Effects of various parameters on grafting degree were investigated including the amounts of monomer, initiator and stabilizer. The maximum extent of grafting achieved was 0.74%. The graft polymers were characterized using FTIR, water contact angle, thermal, mechanical and XRD studies. Improved hydrophilic and mechanical properties were observed for graft polymers.

[Clinicopathologic features and prognosis of young renal tumors with tumor thrombus].

OBJECTIVE: To retrospectively analyze clinical data of patients under 40 years old who underwent surgical treatment for renal tumors with tumor thrombus from January 2016 to December 2022 at Peking University Third Hospital, and to evaluate the surgical effect and investigate the relationship between clinicopathological characteristics and prognosis. METHODS: The clinical data of 17 young patients with renal tumor thrombus were retrospectively analyzed, and the clinicopathological features and prognosis were summarized. The patients were grouped according to the presence or absence of symptoms, 2017 American Joint Committee on Cancer (AJCC) clinical stage, and postoperative combined adjuvant therapy. Kaplan-Meier method was used to plot the survival curve, and Log-rank test was used to compare the differences in postoperative survival time and progression-free survival time between the different groups. The relationship between clinicopathological features and prognosis was analyzed. RESULTS: All the 17 patients received venous tumor thrombectomy, including 16 patients (94.1%) who underwent radical nephrectomy and 1 patient (5.9%) who underwent partial nephrectomy. Twelve patients (70.6%) had symptoms and 5 (29.4%) had no symptoms before operation. A total of 17 renal tumors were observed, with 2 patients (11.8%) identified as benign and 15 patients (88.2%) classified as malignant. Among the malignant tumors, 1 patient (6.7%) was diagnosed as clear cell carcinoma, while the remaining 14 patients (93.3%) were categorized as non-clear cell carcinoma. In terms of tumor stage, 8 patients (53.3%) were classified as stage Ⅲ according to the AJCC classification, while 7 patients (46.7%) were categorized as stage Ⅳ. Additionally, 6 patients (40%) received multiple adjuvant therapy, while 9 patients (60%) did not undergo such treatment. The follow-up period ranged from 2 to 78 months, with a median follow-up of 41 months. During this time, 3 patients (20%) died. The median survival time after surgery was 39.0 (2.3, 77.8) months, and the progression-free survival time was 16.4 (2.3, 77.8) months. There was no significant difference in postoperative survival time and progression-free survival time among young patients with renal tumor with tumor thrombus, based on the presence of symptoms before surgery (P=0.307, P=0.302), clinical stage of AJCC (P=0.340, P=0.492), and postoperative adjuvant therapy (P=0.459, P=0.253) group. CONCLUSION: The pathological types of young patients with renal tumor with tumor thrombus are more complex and varied due to symptoms, and the proportion of non-clear cell carcinoma in malignant tumor with tumor thrombus is higher. Symptomatic and non-clear cell carcinoma may be potentially associated with poor prognosis. Surgical operation combined with adjuvant therapy is a relatively safe and effective treatment for young patients with renal tumor and tumor thrombus.

[Predictive model of early urinary continence recovery based on prostate gland MRI parameters after laparoscopic radical prostatectomy].

OBJECTIVE: Constructing a predictive model for urinary incontinence after laparoscopic radical prostatectomy (LRP) based on prostatic gland related MRI parameters. METHODS: In this study, 202 cases were included. All the patients were diagnosed with prostate cancer by prostate biopsy and underwent LRP surgery in Peking University Third Hospital. The preoperative MRI examination of all the patients was completed within 1 week before the prostate biopsy. Prostatic gland related parameters included prostate length, width, height, prostatic volume, intravesical prostatic protrusion length (IPPL), prostate apex shape, etc. From the first month after the operation, the recovery of urinary continence was followed up every month, and the recovery of urinary continence was based on the need not to use the urine pad all day long. Logistic multivariate regression analysis was used to analyze the influence of early postoperative recovery of urinary continence. Risk factors were used to draw the receiver operator characteristic (ROC) curves of each model to predict the recovery of postoperative urinary continence, and the difference of the area under the curve (AUC) was compared by DeLong test, and the clinical net benefit of the model was evaluated by decision curve analysis (DCA). RESULTS: The average age of 202 patients was 69.0 (64.0, 75.5) years, the average prostate specific antigen (PSA) before puncture was 12.12 (7.36, 20.06) µg/L, and the Gleason score < 7 points and ≥ 7 points were 73 cases (36.2%) and 129 cases (63.9%) respectively, with 100 cases (49.5%) at T1/T2 clinical stage, and 102 cases (50.5%) at T3 stage. The prostatic volume measured by preoperative MRI was 35.4 (26.2, 51.1) mL, the ratio of the height to the width was 0.91 (0.77, 1.07), the membranous urethral length (MUL) was 15 (11, 16) mm, and the IPPL was 2 (0, 6) mm. The prostatic apex A-D subtypes were 67 cases (33.2%), 80 cases (39.6%), 24 cases (11.9%) and 31 cases (15.3%), respectively. The training set and validation set were 141 cases and 61 cases, respectively. The operations of all the patients were successfully completed, and the urinary continence rate was 59.4% (120/202) in the 3 months follow-up. The results of multivariate analysis of the training set showed that the MUL (P < 0.001), IPPL (P=0.017) and clinical stage (P=0.022) were independent risk factors for urinary incontinence in the early postoperative period (3 months). The nomogram and clinical decision curve were made according to the results of multivariate analysis. The AUC value of the training set was 0.885 (0.826, 0.944), and the AUC value of the validation set was 0.854 (0.757, 0.950). In the verification set, the Hosmer-Lemeshow goodness-of-fit test was performed on the model, and the Chi-square value was 5.426 (P=0.711). CONCLUSION: Preoperative MUL, IPPL, and clinical stage are indepen-dent risk factors for incontinence after LRP. The nomogram developed based on the relevant parameters of MRI glands can effectively predict the recovery of early urinary continence after LRP. The results of this study require further large-scale clinical research to confirm.

[Risk factors for massive hemorrhage after radical nephrectomy and removal of venous tumor thrombus].

OBJECTIVE: To investigate and analyze the risk factors of massive hemorrhage in patients with renal cell carcinoma and venous tumor thrombus undergoing radical nephrectomy and removal of venous tumor thrombus. METHODS: From January 2014 to June 2020, 241 patients with renal cancer and tumor thrombus in a single center of urology at Peking University Third Hospital were retrospectively analyzed. All patients underwent radical nephrectomy and removal of venous tumor thrombus. The relevant preoperative indicators, intraoperative conditions, and postoperative data were statistically analyzed by using statistical software of SPSS 18.0. The main end point of the study was intraoperative bleeding volume greater than 2 000 mL. Logistic regression analysis was used to determine the relevant influencing factors. First, single factor Logistic regression was used for preliminary screening of influencing factors, and variables with single factor Logistic regression analysis P < 0.05 were included in multivariate Logistic regression. In all statistical analyses, P < 0.05 is considered statistically significant. RESULTS: Among the 241 patients included, there were 60 cases of massive hemorrhage, 48 males and 12 females, with a median age of 62 years. The number of non-massive hemorrhage was 181. There were 136 males and 45 females, with a median age of 59 years. Univariate analysis showed that the clinical symptoms (both systemic and local symptoms, OR 2.794, 95%CI 1.087-7.181, P=0.033), surgical approach (open surgery, OR 9.365, 95%CI 4.447-19.72, P < 0.001), Mayo grade (Mayo 3-4, OR 5.257, 95%CI 2.806-10.886, P < 0.001), American Society of Anesthesiologists (ASA) score (ASA level 3, OR 2.842, 95%CI 1.338-6.036, P=0.007), preoperative hemoglobin (OR 0.978, 95%CI 0.965-0.991, P=0.001), preoperative platelet count (OR 0.996, 95%CI 0.992-1.000, P=0.037), maximum tumor thrombus width (OR 1.061, 95%CI 1.033-1.091, P < 0.001), Complicated with bland thrombus (OR 4.493, 95%CI 2.264-8.915, P < 0.001), adrenalectomy (OR 3.101, 95%CI 1.614-5.958, P=0.001), segmental resection of the inferior vena cava (OR 2.857, 95%CI 1.395-5.852, P=0.004). There was a statistically significant difference in these aspects(P < 0.05). Multivariate Logistic regression analysis showed that there was a statistically significant difference in surgical approach (open surgery, OR 6.730, 95%CI 2.947-15.368;P < 0.001), Mayo grade (Mayo 3-4, OR 2.294, 95%CI 1.064-4.948, P=0.034), Complicated with bland thrombus (OR 3.236, 95%CI 1.492-7.020, P=0.003). CONCLUSION: Combining the results of univariate and multivariate Logistic regression analysis, the surgical approach, Mayo grade, and tumor thrombus combined with conventional thrombus were associated risk factors for massive hemorrhage during surgery for renal cell carcinoma with tumor thrombus. Patients who undergo open surgery, high Mayo grade, and tumor thrombus combined with conventional thrombus are at a relatively higher risk of massive hemorrhage.

[Near-infrared targeted probe designed for intraoperative imaging of prostatic neurovascular bundles].

OBJECTIVE: To investigate the imaging effect of a near-infrared fluorescent targeted probe ICG-NP41 on the neurovascular bundles (NVB) around the prostate in rats. METHODS: A near-infrared fluorescent targeted probe ICG-NP41 was synthesized. An animal model for NVB imaging was established using Sprague-Dawley rats (250-400 g). Experiments were conducted using a custom-built near-infrared windowⅡ(NIR-Ⅱ) small animal in vivo imaging system, and images collected were processed using ImageJ and Origin. The fluorescence signal data were statistically analyzed using GraphPad Prism. The signal-to-background ratio (SBR) for NVB was quantitatively calculated to explore the effective dosage and imaging time points. Finally, paraffin pathology sections and HE staining were performed on the imaging structures. RESULTS: Except for rats in the control group (n=2), right-sided NVB of the rats injected with ICG-NP41 (n=2 per group) were all observed in NIR-Ⅱ fluorescence mode 2 h and 4 h after administration. At 2 h and 4 h, average SBR of cavernous nerve in 2 mg/kg group in fluorescence mode was 1.651±0.142 and 1.619±0.110, respectively, both higher than that in white light mode (1.111±0.036), with no significant difference (P>0.05); average SBR of 4 mg/kg group in fluorescence mode were 1.168±0.066 and 1.219±0.118, respectively, both higher than that in white light mode (1.081±0.040), with no significant difference (P>0.05). At 2 h and 4 h, the average SBR of 2 mg/kg and 4 mg/kg groups in fluorescence mode were higher than that of the control group (SBR=1), the average SBR of the 2 mg/kg group was higher than that of the 4 mg/kg group, and all the above with no significant difference (P>0.05). The average diameter of the nerve measured by full width at half maxima method was about (178±15) µm. HE staining of paraffin sections showed the right major pelvic ganglion. CONCLUSION: The near-infrared fluorescent targeted probe ICG-NP41 can be used for real-time imaging of the NVB around the prostate in rats, providing a potential feasible solution for localizing NVB in real time during nerve-sparing radical prostatectomy.

Graphene Quantum Dots Pinned on Nanosheets-Assembled NiCo-LDH Hollow Micro-Tunnels: Toward High-Performance Pouch-Type Supercapacitor via the Regulated Electron Localization.

A combined delicate micro-/nano-architecture and corresponding surface modification at the nanometer level can co-tailor the physicochemical properties to realize an advanced supercapacitor electrode material. Herein, nanosheets-assembled nickel-cobalt-layered double hydroxide (NiCo-LDH) hollow micro-tunnels strongly coupled with higher-Fermi-level graphene quantum dots (GQDs) are reported. The unique hollow structure endows the electrolyte accessible to more electroactive sites, while 2D nanosheets have excellent surface chemistry, which favors rapid ion/electron transfer, synergistically resulting in more super-capacitive activities. The experimental and density functional theory calculations recognize that such a precise decoration generally tunes the charge density distribution at the near-surface due to the Fermi-level difference of two components, thus regulating the electron localization, while decorating with conductive GQDs co-improves the charge mobility, affording superior capacitive response and electrode integrity. The as-acquired GQDs@LDH-2 electrode yields excellent capacitance reaching ≈1628 F g-1 at 1 A g-1 and durable cycling longevity (86.2% capacitive retention after 8000 cycles). When coupled with reduced graphene oxide-based negative electrode, the hybrid device unveils an impressive energy/power density (46 Wh kg-1 / 7440 W kg-1 ); moreover, a flexible pouch-type supercapacitor can be constructed based on this hybrid system, which holds high mechanical properties and stable energy and power output at various situations, showcasing superb application prospects.

Untangling the mechanics of entanglements in slide-ring gels towards both super-deformability and toughness.

Entanglement plays a critical role in determining the dynamic properties of polymer systems, e.g., resulting in slip links and pulley effects for achieving large deformation and high strength. Although it has been studied for decades, the mechanics of entanglements for stiffness-toughness conflict is not well understood. In this study, topological knot theory incorporating an extended tube model is proposed to understand the entanglements in a slide-ring (SR) gel, which slips over a long distance to achieve large deformation and high toughness via the pulley effect. Based on topological knot theory, the sliding behavior and pulley effect of entanglements among molecular chains and cross-linked rings are thoroughly investigated. Based on rubber elasticity theory, a free-energy function is formulated to describe mechanical toughening and slipping of topological knots, while the SR gel retains the same binding energy. Finally, the effectiveness of the proposed model is verified using both finite element analysis and experimental results reported in the literature.

Dynamics of 5R-Tg Base Flipping in DNA Duplexes Based on Simulations─Agreement with Experiments and Beyond.

Damaged or mismatched DNA bases are normally thought to be able to flip out of the helical stack, providing enzymes with access to the faulty genetic information otherwise hidden inside the helix. Thymine glycol (Tg) is one of the most common products of nucleic acid damage. However, the static and dynamic structures of DNA duplexes affected by 5R-Tg epimers are still not clearly understood, including the ability of these to undergo spontaneous base flipping. Structural effects of the 5R-Tg epimers on the duplex DNA are herein studied using molecular dynamics together with reliable DFT based calculations. In comparison with the corresponding intact DNA, the cis-5R,6S-Tg epimer base causes little perturbation to the duplex DNA, and a barrier of 4.9 kcal mol-1 is obtained by meta-eABF for cis-5R,6S-Tg base flipping out of the duplex DNA, comparable to the 5.4 kcal mol-1 obtained for the corresponding thymine flipping in intact DNA. For the trans-5R,6R-Tg epimer, three stable local structures were identified, of which the most stable disrupts the Watson-Crick hydrogen-bonded G5/C20 base pair, leading to conformational distortion of the duplex. Interestingly, the relative barrier height of the 5R-Tg flipping is only 1.0 kcal mol-1 for one of these trans-5R,6R-Tg epimers. Water bridge interactions were identified to be essential for 5R-Tg flipping. The study clearly demonstrates the occurrence of partial trans-5R,6R-Tg epimer flipping in solution.

Self-Accelerating Interfacial Catalytic Elimination of Gaseous Sulfur-Containing Volatile Organic Compounds as Microbubbles in a Facet-Engineered Three-Dimensional BiOCl Sponge Fenton-Like Process.

The elimination of gaseous sulfur-containing volatile organic compounds (S-VOCs) by a microbubble-assisted Fenton-like process is an innovative strategy. Herein, we established a microbubble-assisted Fenton-like process to eliminate malodorous microbubble CH3SH as representative gaseous S-VOCs, in which BiOCl nanosheets loaded on a three-dimensional sponge were exposed to (001) or (010) facets and induced Fenton-like interface reactions. Intriguingly, the microbubble-assisted Fenton-like process significantly removed 99.9% of CH3SH, higher than that of the macrobubble-assisted Fenton-like process (39.0%). The self-accelerating interfacial catalytic mechanism was in-depth identified by in situ ATR-FTIR, PTR-TOF-MS, EPR, and DFT computational study. The extraordinary elimination performance of microbubble-assisted Fenton-like process lies in the enhancing dissolution/mass transfer of gaseous CH3SH in the gas/liquid phase and the tight contact between CH3SH-microbubbles and 3D-BiOCl sponge due to the low rising velocity (0.13 mm s-1) and negative charge (-45.53 mV) of CH3SH-microbubbles, as well as the effective generation of 1O2 by activating the enriched dissolved oxygen in CH3SH-microbubble via effective electron-polarized sites on 3D-BiOCl sponge. Furthermore, CH3SH-microbubbles transferred electrons to H2O2 through electron-rich oxygen vacancy centers of the 3D-BiOCl sponge to generate more •OH, thus achieving excellent elimination performance. Overall, this study demonstrates the enhanced self-accelerating interfacial catalytic elimination by S-VOC microbubble and provides the underlying mechanisms.

Exploration of Plastid Phylogenomic Conflict Yields New Insights into the Deep Relationships of Leguminosae.

Phylogenomic analyses have helped resolve many recalcitrant relationships in the angiosperm tree of life, yet phylogenetic resolution of the backbone of the Leguminosae, one of the largest and most economically and ecologically important families, remains poor due to generally limited molecular data and incomplete taxon sampling of previous studies. Here, we resolve many of the Leguminosae's thorniest nodes through comprehensive analysis of plastome-scale data using multiple modified coding and noncoding data sets of 187 species representing almost all major clades of the family. Additionally, we thoroughly characterize conflicting phylogenomic signal across the plastome in light of the family's complex history of plastome evolution. Most analyses produced largely congruent topologies with strong statistical support and provided strong support for resolution of some long-controversial deep relationships among the early diverging lineages of the subfamilies Caesalpinioideae and Papilionoideae. The robust phylogenetic backbone reconstructed in this study establishes a framework for future studies on legume classification, evolution, and diversification. However, conflicting phylogenetic signal was detected and quantified at several key nodes that prevent the confident resolution of these nodes using plastome data alone. [Leguminosae; maximum likelihood; phylogenetic conflict; plastome; recalcitrant relationships; stochasticity; systematic error.].

Feasibility and reproducibility of T2 mapping and DWI for identifying malignant lymph nodes in rectal cancer.

OBJECTIVES: To evaluate the diagnostic value and reproducibility of T2 mapping versus apparent diffusion coefficients (ADC) for identifying malignant lymph nodes in patients with non-mucinous rectal adenocarcinoma. METHODS: High-resolution magnetic resonance imaging, diffusion-weighted imaging, and T2 mapping were performed on patients with suspected metastatic lymph nodes in the mesorectum or around the superior rectal artery with a short-axis diameter of 4-10 mm. The T2 and ADC values of pathology-confirmed metastatic versus non-metastatic lymph nodes were compared using the independent-samples t test and receiver operating characteristic curves. Intra- and inter-observer reproducibility were tested. The cutoff value for T2 relaxation time was determined. RESULTS: In total, 67 lymph nodes underwent histological analysis, with 24 in the non-metastatic and 43 in the metastatic groups. Intra- and inter-observer agreements for T2 values were 0.999 and 0.998, respectively, which were higher than the ADC values of 0.924 and 0.844, respectively. The mean T2 and ADC values for metastatic lymph nodes (65 ± 7.8 ms and 1.17 ± 0.16 × 10-3 mm2/s, respectively) were significantly lower than for benign lymph nodes(83 ± 5.7 ms and 1.29 ± 0.15 × 10-3 mm2/s, respectively). T2 values had a higher AUC value of 0.990 than the AUC value for ADC of 0.729. With a cutoff value of 77 ms, sensitivity and specificity for T2 values were 95% and 96%, respectively. CONCLUSIONS: T2 mapping had higher diagnostic efficacy and reproducibility than ADC and may be useful in differentiating metastatic from non-metastatic lymph nodes in rectal cancer. KEY POINTS: • Mean T2 values were significantly shorter for malignant versus benign LNs in patients with non-mucinous rectal adenocarcinoma. • The diagnostic efficacy and reproducibility of T2 values were excellent and superior to ADC values.