Design, synthesis, and anti-oomycete activity of 3-acyloxymaltol/ethyl maltol derivatives.

Twenty 3-acyloxymaltol/ethyl maltol derivatives (7a-j and 8a-j) were synthesized and evaluated in vitro for their anti-oomycete activity against Phytophthora capsici, respectively. Among all of twenty derivatives, more than half of the compounds 7f, 7h, 8a-h and 8j had anti-oomycete activity higher than the positive control zoxamide (EC50 = 22.23 mg/L), and the EC50 values of 18.66, 20.32, 12.80, 16.18, 10.59, 14.98, 16.80, 10.36, 15.32, 12.64, and 13.59 mg/L, respectively. Especially, compounds 8c and 8f exhibited the best anti-oomycete activity against P. capsici with EC50 values of 10.59 and 10.36 mg/L, respectively. Overall, hydroxyl group of maltol/ethyl maltol is important active modification site.

Characteristics and Controlling Factors of Methane Adsorption of the Longmaxi Shale in Northeastern Chongqing: Implications for Shale Gas Occurrence in Complex Structural Areas.

Accurately determining the adsorption capacity of Longmaxi shale in complex structural areas is crucial for evaluating the shale gas resources in northeastern Chongqing. However, studies on the pore characteristics and methane adsorption capacity of these Longmaxi shales are currently limited. In this paper, we collected core samples from the YDB-1 well in northeastern Chongqing and determined the pore structure and adsorption capacity of the Longmaxi shale using low-pressure gas adsorption and high-temperature, high-pressure methane adsorption experiments, respectively. The results indicate that the adsorption capacity of shale in complex structural areas is significantly positively correlated with the organic matter (OM) content, weakly positively correlated with the quartz content, and weakly negatively correlated with clay minerals. Meanwhile, gas-in-place content is simultaneously controlled by the pressure and temperature of the reservoir, and with increasing depth, the adsorbed gas rapidly increases to a maximum value (at 0.8 km) and then slowly decreases, whereas the free gas continuously increases. Compared with the shale in the stable structural areas, the Longmaxi shale in complex structural areas usually develops OM-hosted pores and intergranular pores of OM and minerals and contains more micropores due to tectonic compression, resulting in a relatively larger specific surface area and adsorption capacity. This is the reason shale in complex structural areas has high development potential. The final result can provide an important basis for the evaluation of the gas content and the optimization of dessert areas in the Lower Paleozoic shale gas in southern China.

Associations of Cadmium Exposure with Peripheral Blood Cell Subtype Counts and Indices in Cadmium-Poisoned Mice.

This research was designed to investigate the effects of cadmium on blood cell injury in cadmium-poisoned mice. Twenty mice were randomly divided into two groups: control group and model group. The control group was intraperitoneally injected with normal saline every day and the model group was intraperitoneally injected with 1.4 mg/kg cadmium solution every day. The experimental period was 28 days. The blood of the mice was collected for detection and hematological analysis. The results demonstrated that cadmium increased the number of white blood cells and the number of neutrophils in mice. Cadmium reduced the number of eosinophils, the number of basophils, the number of monocytes, the amount of lymphocytes, the number of red blood cells, the hemoglobin concentration, mean corpusular volume, mean corpusular hemoglobin, mean corpusular hemoglobin concentration, and the number of platelets in mice. In summary, cadmium caused some damage to white blood cells, red blood cells, and platelets in mice, but the direction of damage to different cells was inconsistent. The possible reason for this result is that cadmium damages the generation of blood cells, and the body takes corresponding defense measures.

Effect of cadmium on histopathological injuries and ultra-structural changes of kidney of the turtle Mauremys reevesii.

This research investigated the effect of cadmium on the tissue and cell of kidney of the turtle Mauremys reevesii. Twenty turtles were injected with cadmium at 0, 7.5, 15, 30 mg/kg separately and five turtles were taken in each group at two weeks after exposure. Kidneys were immediately excised and macroscopic pathological changes were observed, then the kidneys were fixed in 4% paraformaldehyde for histopathological examination and fixed in 2.5% (v/v) glutaraldehyde for examination of ultra-structure. The tissues of kidney presented varying degrees of histopathological lesions in cadmium treated turtles by a dose-dependent manner under the light microscope. Under transmission electron microscope, renal tubules cells presented varying degrees of dose-dependent lesions. The results indicated that cadmium can cause cell damages to the kidney, in particular to the mitochondria. Mitochondria can be used as one biomarker in the monitoring of cadmium pollution and its quantitative risk assessments.

New insights into black carbon light absorption enhancement: A comprehensive analysis of two differential behaviors.

High uncertainty in optical properties of black carbon (BC) involving heterogeneous chemistry has recently attracted increasing attention in the field of atmospheric climatology. To fill the gap in BC optical knowledge so as to estimate more accurate climate effects and serve the response to global warming, it is beneficial to conduct site-level studies on BC light absorption enhancement (Eabs) characteristics. Real-time surface gas and particulate pollutant observations during the summer and winter over Wuhan were utilized for the analysis of Eabs simulated by minimum R squared (MRS), considering two distinct atmospheric conditions (2015 and 2017). In general, differences in aerosol emissions led to Eabs differential behaviors. The summer average of Eabs (1.92 ± 0.55) in 2015 was higher than the winter average (1.27 ± 0.42), while the average (1.11 ± 0.20) in 2017 summer was lower than that (1.67 ± 0.69) in winter. Eabs and RBC (representing the mass ratio of non-refractory constituents to elemental carbon) constraints suggest that Eabs increased with the increase in RBC under the ambient condition enriched by secondary inorganic aerosol (SIA), with a maximum growth rate of 70.6% in 2015 summer. However, Eabs demonstrated a negative trend against RBC in 2017 winter due to the more complicated mixing state. The result arose from the opposite impact of hygroscopic SIA and absorbing OC/irregular distributed coatings on amplifying the light absorbency of BC. Furthermore, sensitivity analysis revealed a robust positive correlation (R > 0.9) between aerosol chemical compositions (including sulfate, nitrate, ammonium and secondary organic carbon), which could be significantly perturbed by only a small fraction of absorbing materials or restructuring BC through gaps filling. The above findings not only deepen the understanding of BC, but also provide useful information for the scientific decision-making in government to mitigate particulate pollution and obtain more precise BC radiative forcing.

Transparent Cellulose/Multi-Walled Carbon Nanotube Hybrids with Improved Ultraviolet-Shielding Properties Prepared from Cotton Textile Waste.

Plastics offer many advantages and are widely used in various fields. Nevertheless, most plastics derived from petroleum are slow to degrade due to their stable polymer structure, posing serious threats to organisms and ecosystems. Thus, developing environmentally friendly and biodegradable plastics is imperative. In this study, biodegradable cellulose/multi-walled carbon nanotube (MCNT) hybrid gels and films with improved ultraviolet-shielding properties were successfully prepared using cotton textile waste as a resource. It was proven that MCNTs can be dispersed evenly in cellulose without any chemical or physical pretreatment. It was found that the contents of MCNTs had obvious effects on the structures and properties of hybrid films. Particularly, the averaged transmittance of cellulose/MCNT composite films in the range of 320-400 nm (T320-400) and 290-320 nm (T290-320) can be as low as 19.91% and 16.09%, when the content of MCNTs was 4.0%, much lower than those of pure cellulose films (T320-400: 84.12% and T290-320: 80.03%). Meanwhile, the water contact angles of the cellulose/MCNT films were increased by increasing the content of MCNTs. Most importantly, the mechanical performance of cellulose/MCNT films could be controlled by the additives of glycerol and MCNTs. The tensile strength of the cellulose/MCNT films was able to reach as high as 20.58 MPa, while the elongation at break was about 31.35%. To summarize, transparent cellulose/MCNT composites with enhanced ultraviolet-shielding properties can be manufactured successfully from low-cost cotton textile waste, which is beneficial not only in terms of environmental protection, but also the utilization of natural resources.

Chicken gasdermins mediate pyroptosis after the cleavage by caspases.

Gasdermin (GSDM) proteins are executioners of pyroptosis in many species. Gasdermin proteins can be cleaved at their linker region between the amino domain (NT) and carboxyl domain (CT) by enzymes. The released GSDM-NTs bind cell membrane and form pores, thereby leading to the release of cellular components and lytic cell death. GSDM-mediated pyroptosis is considered to play important role in immune responses. However, little is known about the GSDM proteins and GSDM-mediated pyroptosis in birds. In the current study, genes encoding chicken gasdermin A (chGSDMA) and chGSDME were cloned. The cleavage of chGSDMA and chGSDME by chicken caspase-1 (chCASP1), chCASP3 and chCASP7 and the cleavage sites were determined. The chGSDMA-NT obtained form chCASP1-mediated cleavage and chGSDME-NT obtained from chCASP3/chCASP7-mediated cleavage could bind and damage cell membrane and lead to cell death of HEK293 cells. chGSDMA-NT also strongly localized to and formed puncta in nucleus. Besides, both chGSDMA-NT and chGSDME-NT showed growth inhibition and bactericidal activity to bacteria. In chickens challenged with Pasteurella multocida and Salmonella typhimurium, the expression of chGSDMA and chGSDME was upregulated and the activation of chCASP3 and the cleavage of chGSDME were observed. The work provides essential information for expanding our knowledge on pyroptosis in birds.

Brain radiotherapy and anlotinib control primary cardiac angiosarcoma with metastases: A case report.

RATIONALE: Primary cardiac angiosarcoma (PCA) is a rare and fatal disease with a poor prognosis. Whether the survival of PCA patients can be prolonged with additional treatment following complete surgical excision is controversial. PATIENT CONCERNS: In this case study, a 52-year-old male complained of chest tightness and pain for 7 days before admission into the hospital. Subsequently, he revisited the hospital because of dizziness and headache. DIAGNOSES: Initially, the patient was diagnosed with PCA in the right atrium by thoracic computed tomography (CT). Palliative resection identified brain, lung, and liver metastases. INTERVENTION: The patient accepted multimodal combination therapy, including first-line chemotherapy and then second-line anlotinib concurrent with brain radiotherapy and immunotherapy. OUTCOME: Although anlotinib combined with brain radiotherapy controlled the growth of intracranial lesions, progression-free survival (PFS) was only 5 months, and the overall survival (OS) was only 12 months. LESSON: The treatment for metastatic PCA needs an in-depth exploration.

Chemical Cross-Linking Cellulose Aerogel-Based Triboelectric Nanogenerators for Energy Harvesting and Sensing Human Activities.

Zinc oxide (ZnO) is a widely employed material for enhancing the performance of cellulose-based triboelectric nanogenerators (C-TENGs). Our study provides a novel chemical interpretation for the improved output efficiency of ZnO in C-TENGs. C-TENGs exhibit excellent flexibility and integration, achieving a maximum open-circuit voltage (Voc) of 210 V. The peak power density is 54.4 µW/cm2 with a load resistance of 107 Ω, enabling the direct powering of 191 light-emitting diodes with the generated electrical output. Moreover, when deployed as self-powered sensors, C-TENGs exhibit prolonged operational viability and responsiveness, adeptly discerning bending and motion induced by human interaction. The device's sensitivity, flexibility, and stability position it as a promising candidate for a diverse array of energy-harvesting applications and advanced healthcare endeavors. Specifically, envisaging sensitized wearable sensors for human activities underscores the multifaceted potential of C-TENGs in enhancing both energy-harvesting technologies and healthcare practices.

Proposals for gas-detection improvement of the FeMPc monolayer towards ethylene and formaldehyde by using bimetallic synergy.

Development and fabrication of a novel gas sensor with superb performance are crucial for enabling real-time monitoring of ethylene (C2H4) and formaldehyde (H2CO) emissions from industrial manufacture. Herein, first-principles calculations and AIMD simulations were carried out to investigate the effect of the Fe-M dimer on the adsorption of C2H4 and H2CO on metal dimer phthalocyanine (FeMPc, M = Ti-Zn) monolayers, and the electronic structures and sensing properties of the above adsorption systems were systematically discussed. The results show that the FeMPc (M = Ti, V, Cr, Mn) monolayers interact with C2H4 and H2CO by chemisorption except for the FeMnPc/H2CO system, while the other adsorption systems are all characterized by physisorption. Interestingly, the adsorption strength of C2H4 and H2CO can be effectively regulated by the bimetallic synergy of the Fe-M dimer. Moreover, the FeCrPc and FeMnPc monolayers exhibit excellent sensitivity towards C2H4 and H2CO, and have short recovery time (4.69 ms-2.31 s) for these gases at room temperature due to the effective surface diffusion at 300 K. Consequently, the FeCrPc and FeMnPc materials can be utilized as high-performance, reusable gas sensors for detecting C2H4 and H2CO, and have promising applications in monitoring the release of ethylene and formaldehyde from industrial processes.

Secure multi-path routing for Internet of Things based on trust evaluation.

In the realm of the Internet of Things (IoT), ensuring the security of communication links and evaluating the safety of nodes within these links remains a significant challenge. The continuous threat of anomalous links, harboring malicious switch nodes, poses risks to data transmission between edge nodes and between edge nodes and cloud data centers. To address this critical issue, we propose a novel trust evaluation based secure multi-path routing (TESM) approach for IoT. Leveraging the software-defined networking (SDN) architecture in the data transmission process between edge nodes, TESM incorporates a controller comprising a security verification module, a multi-path routing module, and an anomaly handling module. The security verification module ensures the ongoing security validation of data packets, deriving trust scores for nodes. Subsequently, the multi-path routing module employs multi-objective reinforcement learning to dynamically generate secure multiple paths based on node trust scores. The anomaly handling module is tasked with handling malicious switch nodes and anomalous paths. Our proposed solution is validated through simulation using the Ryu controller and P4 switches in an SDN environment constructed with Mininet. The results affirm that TESM excels in achieving secure data forwarding, malicious node localization, and the secure selection and updating of transmission paths. Notably, TESM introduces a minimal 12.4% additional forwarding delay and a 5.46% throughput loss compared to traditional networks, establishing itself as a lightweight yet robust IoT security defense solution.

A machine learning model identifies M3-like subtype in AML based on PML/RARα targets.

The typical genomic feature of acute myeloid leukemia (AML) M3 subtype is the fusion event of PML/RARα, and ATRA/ATO-based combination therapy is current standard treatment regimen for M3 subtype. Here, a machine-learning model based on expressions of PML/RARα targets was developed to identify M3 patients by analyzing 1228 AML patients. Our model exhibited high accuracy. To enable more non-M3 AML patients to potentially benefit from ATRA/ATO therapy, M3-like patients were further identified. We found that M3-like patients had strong GMP features, including the expression patterns of M3 subtype marker genes, the proportion of myeloid progenitor cells, and deconvolution of AML constituent cell populations. M3-like patients exhibited distinct genomic features, low immune activity and better clinical survival. The initiative identification of patients similar to M3 subtype may help to identify more patients that would benefit from ATO/ATRA treatment and deepen our understanding of the molecular mechanism of AML pathogenesis.

The profile of HIV-1 drug resistance in Shanghai, China: a retrospective study from 2017 to 2021.

BACKGROUND: HIV-1 drug resistance is a huge challenge in the era of ART. OBJECTIVES: To investigate the prevalence and characteristics of acquired HIV-1 drug resistance (ADR) in Shanghai, China. METHODS: An epidemiological study was performed among people living with human immunodeficiency virus (PLWH) receiving ART in Shanghai from January 2017 to December 2021. A total of 8669 PLWH were tested for drug resistance by genotypic resistance testing. Drug resistance mutations (DRMs) were identified using the Stanford University HIV Drug Resistance Database program. RESULTS: Ten HIV-1 subtypes/circulating recombinant forms (CRFs) were identified, mainly including CRF01_AE (46.8%), CRF07_BC (35.7%), B (6.4%), CRF55_01B (2.8%) and CRF08_BC (2.4%). The prevalence of ADR was 48% (389/811). Three NRTI-associated mutations (M184V/I/L, S68G/N/R and K65R/N) and four NNRTI-associated mutations (V179D/E/T/L, K103N/R/S/T, V106M/I/A and G190A/S/T/C/D/E/Q) were the most common DRMs. These DRMs caused high-level resistance to lamivudine, emtricitabine, efavirenz and nevirapine. The DRM profiles appeared to be significantly different among different subtypes. CONCLUSIONS: We revealed HIV-1 subtype characteristics and the DRM profile in Shanghai, which provide crucial guidance for clinical treatment and management of PLWH.

Comparison of in vitro synergy between polymyxin B or colistin in combination with 16 antimicrobial agents against multidrug-resistant Acinetobacter baumannii isolates.

PURPOSES: This study determined the synergy of polymyxin B (POLB) and colistin (COL) with 16 other tested antimicrobial agents in the inhibition of multidrug-resistant Acinetobacter baumannii (MDR-AB). METHODS: We used chequerboard assays to determine synergy between the drugs against 50 clinical MDR-AB from a tertiary hospital in the Zhejiang province in 2019, classifying combinations as either antagonistic, independent, additive, or synergistic. The efficacy of hit combinations which showed highest synergistic rate were confirmed using time-kill assays. RESULTS: Both POLB and COL displayed similar bactericidal effects when used in combination with these 16 tested drugs. Antagonism was only observed for a few strains (2%) exposed to a combination of POLB and cefoperazone/sulbactam (CSL). A higher percentage of synergistic combinations with POLB and COL were observed with rifabutin (RFB; 90%/96%), rifampicin (RIF; 60%/78%) and rifapentine (RFP; 56%/76%). Time-kill assays also confirmed the synergistic effect of POLB and rifamycin class combinations. 1/2 MIC rifamycin exposure can achieve bacterial clearance when combined with 1/2 MIC POLB or COL. CONCLUSION: Nearly no antagonism was observed when combining polymyxins with other drugs by both chequerboard and time-kill assays, suggesting that polymyxins may be effective in combination therapy. The combinations of POLB/COL with RFB, RIF, and RFP displayed neat synergy, with RFB showing the greatest effect.

Efficient design of energy microgrid management system: A promoted Remora optimization algorithm-based approach.

Microgrids are a promising solution for decentralized energy generation and distribution, offering reliability, efficiency, and resilience. These small-scale power systems can operate independently or connect to the main grid, providing greater reliability and resilience. However, integrating renewable energy into microgrids presents challenges due to their unpredictable nature and fluctuating load of electricity. Energy management strategies play a crucial role in optimizing the operation of microgrids, aiming to balance electricity supply and demand, maximize renewable energy utilization, and minimize operational costs. Various approaches have been proposed for energy management in microgrids, including optimization algorithms, machine learning techniques, and intelligent control systems. This study proposes an optimized and efficient strategy for microgrids operating in both independent and grid-connected modes, focusing on microgrids that utilize a combination of solar and green energy sources. The proposed approach, based on the Promoted Remora Optimization (PRO) algorithm, aims to meet load power requirements at the lowest possible cost while ensuring constant DC bus voltage and safeguarding batteries against overcharging and depletion. The CRO method effectively optimized the charging process, maintaining a consistent level of charge and achieving a final SoC of 33.37 %-33.60 %. It also demonstrated high system efficiency, with an average of 87.99 %, and a range of 87.80 %-88.03 %. The optimizer efficiency ranged from 83.12 % to 86.52 %, with an average of 86.46 %. The CRO method also achieved reasonable operating costs, with a cost per power of $0.1687/kW to $0.1699/kW and a daily cost of $1,379,595 to $1,479,998. Overall, the CRO method showed promise in optimizing the charging process in terms of efficiency and cost-effectiveness. Comparative analysis with existing literature is conducted to evaluate the effectiveness of the proposed approach, demonstrating its superior results compared to other energy management strategies for microgrids. This study contributes to the field of microgrid energy management by providing a novel approach based on the PRO algorithm and demonstrating its effectiveness through comparative analysis.

Dual-modal radiomics nomogram based on contrast-enhanced ultrasound to improve differential diagnostic accuracy and reduce unnecessary biopsy rate in ACR TI-RADS 4-5 thyroid nodules.

BACKGROUND: American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS, TR) 4 and 5 thyroid nodules (TNs) demonstrate much more complicated and overlapping risk characteristics than TR1-3 and have a rather wide range of malignancy possibilities (> 5%), which may cause overdiagnosis or misdiagnosis. This study was designed to establish and validate a dual-modal ultrasound (US) radiomics nomogram integrating B-mode ultrasound (BMUS) and contrast-enhanced ultrasound (CEUS) imaging to improve differential diagnostic accuracy and reduce unnecessary fine needle aspiration biopsy (FNAB) rates in TR 4-5 TNs. METHODS: A retrospective dataset of 312 pathologically confirmed TR4-5 TNs from 269 patients was collected for our study. Data were randomly divided into a training dataset of 219 TNs and a validation dataset of 93 TNs. Radiomics characteristics were derived from the BMUS and CEUS images. After feature reduction, the BMUS and CEUS radiomics scores (Rad-score) were built. A multivariate logistic regression analysis was conducted incorporating both Rad-scores and clinical/US data, and a radiomics nomogram was subsequently developed. The performance of the radiomics nomogram was evaluated using calibration, discrimination, and clinical usefulness, and the unnecessary FNAB rate was also calculated. RESULTS: BMUS Rad-score, CEUS Rad-score, age, shape, margin, and enhancement direction were significant independent predictors associated with malignant TR4-5 TNs. The radiomics nomogram involving the six variables exhibited excellent calibration and discrimination in the training and validation cohorts, with an AUC of 0.873 (95% CI, 0.821-0.925) and 0.851 (95% CI, 0.764-0.938), respectively. The marked improvements in the net reclassification index and integrated discriminatory improvement suggested that the BMUS and CEUS Rad-scores could be valuable indicators for distinguishing benign from malignant TR4-5 TNs. Decision curve analysis demonstrated that our developed radiomics nomogram was an instrumental tool for clinical decision-making. Using the radiomics nomogram, the unnecessary FNAB rate decreased from 35.3 to 14.5% in the training cohort and from 41.5 to 17.7% in the validation cohorts compared with ACR TI-RADS. CONCLUSION: The dual-modal US radiomics nomogram revealed superior discrimination accuracy and considerably decreased unnecessary FNAB rates in benign and malignant TR4-5 TNs. It could guide further examination or treatment options.

Flavonoid 4,4'-dimethoxychalcone selectively eliminates senescent cells via activating ferritinophagy.

Flavonoids are bioactive natural polyphenolic compounds with health benefits, including anti-tumor, anti-inflammatory and anti-aging effects. Our previous studies revealed that a flavonoid 4,4'-dimethoxychalcone (DMC) induced ferroptosis via inhibiting ferrochelatase (FECH). However, the effect of DMC on cellular senescence is unknown. In the present study, we found that DMC treatment selectively eliminated senescent cells, and DMC alone or a combination of DMC and quercetin or dasatinib showed high efficiency in the clearance of senescent cells. We identified FECH was highly expressed in senescent cells compared to non-senescent cells. Mechanistically, we found that DMC inhibited FECH and induced ferritinophagy, which led to an increase of labile iron pool, triggering ferroptosis of senescent cells. Importantly, we found that DMC treatment prevented hair loss, improved motor coordination, and reduced the expression of several senescence-associated secretory phenotype factors (IL-6, IL-1ß, CXCL-10, and MMP12) in the liver of old mice. Collectively, we revealed that, through the induction of ferroptosis, DMC holds the promise as a new senolytics to prevent age-related pathologies.

Genomic Characteristics of the New HIV-1 CRF07_BC K28E32 Variant.

Accompanied with the appearance and prevalence of the new K28E32 variant among men who have sex with men, HIV-1 circulating recombinant form 07_BC (CRF07_BC) was becoming the most predominant subtype circulating in China. The K28E32 variant with five specific mutations in reverse transcriptase coding region appears to have significantly higher in vitro HIV-1 replication ability than the wild-type strain. In this study, we characterized the special mutations/substitutions in the K28E32 variant at the genomic level. Ten specific mutations that rarely appeared in other six main HIV-1 subtypes/CRFs (A-D, CRF01_AE, and CRF02_AG) were identified in the coding genes/regions of the K28E32 variant, including S77L and a novel seven-amino acid detection (32DKELYPL38) (p6Δ7) in p6, I135L in integrase, T189S in Vif, H/Y15L/F in Vpr, I264V/A and LV/LI328-329VG in gp41, and H82C and S97P in Rev. The special locations of the novel p6Δ7, and gp41 mutations I264V/A and LV/LI328-329VG in crucial protein functional domains suggest that these mutations might be functionally important to the K28E32 variant. Furthermore, eight specific substitutions were identified in Rev responsive element (RRE) of the K28E32 variant, and were revealed to increase the stability of RRE structure with a lower minimum free energy. Whether these mutations/substitutions contribute to improved transmissibility of the CRF07_BC K28E32 variant needs to be further confirmed.

Bio-Responsive Sliver Peroxide-Nanocarrier Serves as Broad-Spectrum Metallo-ß-lactamase Inhibitor for Combating Severe Pneumonia.

Metallo-ß-lactamases (MBLs) represent a prevalent resistance mechanism in Gram-negative bacteria, rendering last-line carbapenem-related antibiotics ineffective. Here, a bioresponsive sliver peroxide (Ag2 O2 )-based nanovesicle, named Ag2 O2 @BP-MT@MM, is developed as a broad-spectrum MBL inhibitor for combating MBL-producing bacterial pneumonia. Ag2 O2 nanoparticle is first orderly modified with bovine serum albumin and polydopamine to co-load meropenem (MER) and [5-(p-fluorophenyl)-2-ureido]-thiophene-3-carboxamide (TPCA-1) and then encapsulated with macrophage membrane (MM) aimed to target inflammatory lung tissue specifically. The resultant Ag2 O2 @BP-MT@MM effectively abrogates MBL activity by displacing the Zn2+ cofactor in MBLs with Ag+ and displays potent bactericidal and anti-inflammatory properties, specific targeting abilities, and great bioresponsive characteristics. After intravenous injection, the nanoparticles accumulate prominently at infection sites through MM-mediated targeting . Ag+ released from Ag2 O2 decomposition at the infection sites effectively inhibits MBL activity and overcomes the resistance of MBL-producing bacteria to MER, resulting in synergistic elimination of bacteria in conjunction with MER. In two murine infection models of NDM-1+ Klebsiella pneumoniae-induced severe pneumonia and NDM-1+ Escherichia coli-induced sepsis-related bacterial pneumonia, the nanoparticles significantly reduce bacterial loading, pro-inflammatory cytokine levels locally and systemically, and the recruitment and activation of neutrophils and macrophages. This innovative approach presents a promising new strategy for combating infections caused by MBL-producing carbapenem-resistant bacteria.

Pressure-Driven Polymorphic Transition, Emergent Insulator-To-Metal Transition, and Photoconductivity Switching in Violet Phosphorus.

Polymorphic phase transition is an essential phenomenon in condensed matter that the physical properties of materials may undergo significant changes due to the structural transformation. Phase transition has thus become an important means and dimension for regulating material properties. Herein, this study demonstrates the pressure-induced multi-transition of both structure and physical properties in violet phosphorus, a novel phosphorus allotrope. Under compression, violet phosphorus undergoes sequential polymorphic phase transitions. Concomitant with the first phase transition, violet phosphorus exhibits emergent insulator-metal transition, superconductivity, and dramatic switching from positive to negative photoconductivity. Remarkably, the resistance of violet phosphorus shows a sudden drop of around 107 along with the phase transition. In addition, piezochromism from translucent red to opaque black and suppression of photoluminescence are observed upon compression. Of particular interest is that the sample irreversibly transforms into black phosphorus with a pronounced discrepancy in physical properties from the pristine violet phosphorus after decompression. The abundant polymorphic transitions and property changes in violet phosphorus have significant implications for designing novel pressure-responsive electronic/optoelectronic devices and exploring concealed polymorphic transition materials.