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1.
Nature ; 611(7937): 801-809, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36266581

RESUMO

Genome-wide association studies have identified risk loci linked to inflammatory bowel disease (IBD)1-a complex chronic inflammatory disorder of the gastrointestinal tract. The increasing prevalence of IBD in industrialized countries and the augmented disease risk observed in migrants who move into areas of higher disease prevalence suggest that environmental factors are also important determinants of IBD susceptibility and severity2. However, the identification of environmental factors relevant to IBD and the mechanisms by which they influence disease has been hampered by the lack of platforms for their systematic investigation. Here we describe an integrated systems approach, combining publicly available databases, zebrafish chemical screens, machine learning and mouse preclinical models to identify environmental factors that control intestinal inflammation. This approach established that the herbicide propyzamide increases inflammation in the small and large intestine. Moreover, we show that an AHR-NF-κB-C/EBPß signalling axis operates in T cells and dendritic cells to promote intestinal inflammation, and is targeted by propyzamide. In conclusion, we developed a pipeline for the identification of environmental factors and mechanisms of pathogenesis in IBD and, potentially, other inflammatory diseases.


Assuntos
Meio Ambiente , Herbicidas , Inflamação , Doenças Inflamatórias Intestinais , Intestinos , Animais , Camundongos , Inflamação/induzido quimicamente , Inflamação/etiologia , Inflamação/imunologia , Inflamação/patologia , Doenças Inflamatórias Intestinais/induzido quimicamente , Doenças Inflamatórias Intestinais/etiologia , Doenças Inflamatórias Intestinais/imunologia , Doenças Inflamatórias Intestinais/patologia , Peixe-Zebra , Aprendizado de Máquina , Bases de Dados Factuais , Modelos Animais de Doenças , Intestinos/efeitos dos fármacos , Intestinos/imunologia , Intestinos/metabolismo , Intestinos/patologia , NF-kappa B , Proteína beta Intensificadora de Ligação a CCAAT , Receptores de Hidrocarboneto Arílico , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Herbicidas/efeitos adversos
2.
Nano Lett ; 2024 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-39432866

RESUMO

Reducing the charging voltage is a prerequisite for improving the chargeability and energy efficiency of Zn-air batteries (ZABs). Herein, Fe3+ pumps electrons from oxygen-bridged cobalt (Fe-O-Co) and induces the accelerated charging kinetics. For the liquid ZABs, a charging voltage of around 1.94 V at 10 mA cm-2 was displayed, which slightly increased 2% after continuous cycles for 180 h. A steady charging voltage of around 1.87 V at 10 mA cm-2 was also exhibited for quasi-solid-state ZABs. Control experiments and characterization show that the interactions between the O2- and Fe3+ sites are relatively weaker than those between the O2- and Co3+ sites. Compared with Mn3+, Zn2+, and Cu2+, Fe3+ effectively pumps electrons from Co sites to generate the active species for the oxygen evolution reaction. Thus, the deprotonation behavior and *OH conversion were improved. This work demonstrates the oxygen electron bridge modulated electron transfer between dual metal sites, contributing to the improvement of low-charging-voltage ZABs.

3.
Nano Lett ; 24(15): 4672-4681, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38587873

RESUMO

The bifunctional oxygen electrocatalyst is the Achilles' heel of achieving robust reversible Zn-air batteries (ZABs). Herein, durable bifunctional oxygen electrocatalysis in alkaline media is realized on atomic Fe-N4-C sites reinforced by NixCo3-xO4 (NixCo3-xO4@Fe1/NC). Compared with that of pristine Fe1/NC, the stability of the oxygen evolution reaction (OER) is increased 10 times and the oxygen reduction reaction (ORR) performance is also improved. The steric hindrance alters the valence electron at the Fe-N4-C sites, resulting in a shorter Fe-N bond and enhanced stability of the Fe-N4-C sites. The corresponding solid-state ZABs exhibit an ultralong lifespan (>460 h at 5 mA cm-2) and high rate performance (from 2 to 50 mA cm-2). Furthermore, the structural evolution of NixCo3-xO4@Fe1/NC before and after the OER and ORR as well as charge-discharge cycling is explored. This work develops an efficient strategy for improving bifunctional oxygen electrocatalysis and possibly other processes.

4.
J Am Chem Soc ; 146(23): 16000-16009, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38809420

RESUMO

Constant proportionalities between cells and their intracellular organelles have been widely observed in various types of cells, known as intracellular size scaling. However, the mechanism underlying the size scaling and its modulation by environmental factors in multicomponent systems remain poorly understood. Here, we study the size scaling of membrane-less condensates using microdroplet-encapsulated minimalistic condensates formed by droplet microfluidics and mean-field theory. We demonstrate that the size scaling of condensates is an inherent characteristic of liquid-liquid phase separation. This concept is supported by experiments showing the occurrence of size scaling phenomena in various condensate systems and a generic lever rule acquired from mean-field theory. Moreover, it is found that the condensate-to-microdroplet scaling ratio can be affected by the solute and salt concentrations, with good agreement between experiments and predictions by theory. Notably, we identify a noise buffering mechanism whereby condensates composed of large macromolecules effectively maintain constant volumes and counteract concentration fluctuations of small molecules. This mechanism is achieved through the dynamic rearrangement of small molecules in and out of membrane-free interfaces. Our work provides crucial insights into understanding mechanistic principles that govern the size of cells and intracellular organelles as well as associated biological functions.

5.
Kidney Int ; 105(1): 84-98, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37839695

RESUMO

Clinical verification of adoptively transferred regulatory T cell (Treg) efficacy in transplantation remains challenging. Here, we examined the influence of autologous ex vivo-expanded polyclonal Tregs on kidney graft survival in a clinically relevant non-human primate model. Peripheral blood Tregs were isolated and expanded using artificial antigen presenting cells. Immunosuppression was comprised of tapered tacrolimus and CTLA4 immunoglobulin, in five animals each without or with Treg infusions. Escalating Treg doses were administered 6, 10, 13, 16, 20, 23, 27 and 30 days after transplant. Infused Tregs were monitored for Treg signature, anti-apoptotic (Bcl-2) and proliferation (Ki67) marker expression. Treg infusions prolonged median graft survival time significantly from 35 to 70 days. Treg marker (Ki67 and Bcl-2) expression by infused Tregs diminished after their infusion but remained comparable to that of circulating native Tregs. No major changes in circulating donor-reactive T cell responses or total Treg percentages, or in graft-infiltrating T cell subsets were observed with Treg infusion. However, Treg infusion was associated with significant increases in CD163 expression by circulating HLA-DR+ myeloid cells and elevated levels of circulating soluble CD163. Further, graft-infiltrating CD163+ cells were increased with Treg infusion. Thus, multiple Treg infusions were associated with M2-like myeloid cell enhancement that may mediate immunomodulatory, anti-inflammatory and graft reparative effects.


Assuntos
Primatas , Linfócitos T Reguladores , Animais , Antígeno Ki-67/metabolismo , Rim , Aloenxertos , Células Mieloides , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo
6.
Mod Pathol ; 37(1): 100354, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37844870

RESUMO

Sclerosing pneumocytoma is a rare and distinct lung neoplasm whose histogenesis and molecular alterations are the subject of ongoing research. Our recent study revealed that AKT1 internal tandem duplications (ITD), point mutations, and short indels were present in almost all tested sclerosing pneumocytomas, suggesting that AKT1 mutations are a major driving oncogenic event in this tumor. Although the pathogenic role of AKT1 point mutations is well established, the significance of AKT1 ITD in oncogenesis remains largely unexplored. We conducted comprehensive genomic and transcriptomic analyses of sclerosing pneumocytoma to address this knowledge gap. RNA-sequencing data from 23 tumors and whole-exome sequencing data from 44 tumors were used to obtain insights into their genetic and transcriptomic profiles. Our analysis revealed a high degree of genetic and transcriptomic similarity between tumors carrying AKT1 ITD and those with AKT1 point mutations. Mutational signature analysis revealed COSMIC signatures 1 and 5 as the prevailing signatures of sclerosing pneumocytoma, associated with the spontaneous deamination of 5-methylcytosine and an unknown etiology, respectively. RNA-sequencing data analysis revealed that the sclerosing pneumocytoma gene expression profile is characterized by activation of the PI3K/AKT/mTOR pathway, which exhibits significant similarity between tumors harboring AKT1 ITD and those with AKT1 point mutations. Notably, an upregulation of SOX9, a transcription factor known for its involvement in fetal lung development, was observed in sclerosing pneumocytoma. Specifically, SOX9 expression was prominent in the round cell component, whereas it was relatively lower in the surface cell component of the tumor. To the best of our knowledge, this is the first comprehensive investigation of the genomic and transcriptomic characteristics of sclerosing pneumocytoma. Results of the present study provide insights into the molecular attributes of sclerosing pneumocytoma and a basis for future studies of this enigmatic tumor.


Assuntos
Fosfatidilinositol 3-Quinases , Hemangioma Esclerosante Pulmonar , Humanos , Fosfatidilinositol 3-Quinases/genética , Hemangioma Esclerosante Pulmonar/genética , Hemangioma Esclerosante Pulmonar/patologia , Genômica , Perfilação da Expressão Gênica , RNA
7.
Chemistry ; 30(38): e202401350, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38700514

RESUMO

An unprecedented 1,5-addition/N-1,4-addition cascade reaction is established via palladium hydride catalysis. A variety of polysubstituted dihydropyrrole skeletons are constructed in high yield and with exclusively >20 : 1 diastereoselectivity. An enantioselective protocol of this design is also developed to provide a novel access to enantioenriched dihydropyrroles.

8.
Inflamm Res ; 73(3): 407-414, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38158447

RESUMO

OBJECTIVE AND DESIGN: This study aimed to investigate Axin2 effects on myocardial infarction (MI) using a macrophage Axin2 conditional knockout (cKO) mouse model, RAW264.7 cell line, and human subepicardial tissues from patients with coronary artery bypass graft (CABG). MATERIAL OR SUBJECTS: Axin2 cKO mice showed decreased cardiac function, reduced edema, increased lymphangiogenesis, and improved repair in MI Few studies border zones. Hypoxic macrophages with Axin2 depletion exhibited decreased senescence, elevated IL6 expression, and increased LYVE1 transcription. Senescent macrophages decreased in patients with CABG and low Axin2 expression. TREATMENT: Treatment options included in this study were MI induction in Axin2 cKO mice, in vitro experiments with RAW264.7 cells, and analysis of human subepicardial tissues. METHODS: Assays included MI induction, in vitro experiments, and tissue analysis with statistical tests applied. RESULTS: Axin2 cKO improved cardiac function, reduced edema, enhanced lymphangiogenesis, and decreased senescence. Hypoxic macrophages with Axin2 depletion showed reduced senescence, increased IL6 expression, and elevated LYVE1 transcription. Senescent macrophages decreased in patients with CABG and low Axin2 expression. CONCLUSION: Targeting Axin2 emerges as a novel therapeutic strategy for regulating cardiac lymphatics and mitigating cell senescence post-MI, evidenced by improved outcomes in Axin2-deficient conditions.


Assuntos
Interleucina-6 , Infarto do Miocárdio , Humanos , Camundongos , Animais , Interleucina-6/metabolismo , Infarto do Miocárdio/genética , Macrófagos , Imunidade , Edema/metabolismo , Camundongos Endogâmicos C57BL , Miocárdio , Proteína Axina/genética , Proteína Axina/metabolismo
9.
Environ Sci Technol ; 58(8): 3812-3822, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38358300

RESUMO

Fog harvesting is considered a promising freshwater collection strategy for overcoming water scarcity, because of its environmental friendliness and strong sustainability. Typically, fogging occurs briefly at night and in the early morning in most arid and semiarid regions. However, studies on water collection from short-term fog are scarce. Herein, we developed a patterned surface with highly hydrophilic interconnected microchannels on a superhydrophobic surface to improve droplet convergence driven by the Young-Laplace pressure difference. With a rationally designed surface structure, the optimized water collection rate from mild fog could reach up to 67.31 g m-2 h-1 (6.731 mg cm-2 h-1) in 6 h; this value was over 130% higher than that observed on the pristine surface. The patterned surface with interconnected microchannels significantly shortened the startup time, which was counted from the fog contact to the first droplet falling from the fog-harvesting surface. The patterned surface was also facilely prepared via a controllable strategy combining laser ablation and chemical vapor deposition. The results obtained in outdoor environments indicate that the rationally designed surface has the potential for short-term fog harvesting. This work can be considered as a meaningful attempt to address the practical issues encountered in fog-harvesting research.


Assuntos
Água Doce , Água , Gases , Pressão , Tempo (Meteorologia) , Interações Hidrofóbicas e Hidrofílicas
10.
Hepatol Res ; 54(9): 838-850, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38451566

RESUMO

AIM: We aimed to investigate the prognostic factors for salvage liver transplant in patients with early hepatocellular carcinoma recurrence after hepatectomy. METHODS: This retrospective analysis included 53 patients who underwent salvage living-donor liver transplantation between January 2007 and January 2018. There were 24 and 29 patients in the early (recurrence ≤24 months after primary liver resection) and the late recurrence groups, respectively. RESULTS: In the multivariate Cox regression model, pre-liver transplant downstaging therapy, early recurrence (ER) after primary liver resection , and recurrence-to-liver-transplant ≥12 months were independent risks to predict recurrent hepatocellular carcinoma recurrence after salvage living-donor liver transplantation. Compared with the late recurrence group, the ER group showed lower disease-free survival rates (p < 0.001); however, the overall survival rates did not differ between the two groups (p = 0.355). The 1-, 3-, and 5-year disease-free survival rates were 83.3%, 70.6%, and 66.2%, and 96.0%, 91.6%, and 91.6% in the early and late recurrence groups, respectively. When stratified by recurrence-to-liver transplant time and pre-liver transplant downstaging therapy in the ER group, disease-free survival and overall survival rates were significantly different. CONCLUSION: ER after primary liver resection with advanced tumor status and a longer period of recurrence-to-liver-transplant (≥12 months) have a negative impact on salvage liver transplant. Our findings provide novel recommendations for treatment strategies and eligibility for salvage liver transplant candidates.

11.
Dig Dis Sci ; 69(8): 3069-3078, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38824258

RESUMO

BACKGROUND: In many Asian hepatocellular carcinoma (HCC) guidelines, resection is an option for multiple HCCs. It is difficult to compare small but multiple tumors vs. fewer large tumors in terms of the traditional tumor burden definition. We aimed to evaluate the role of liver resection for multiple HCCs and determine factors associated with survival benefits. METHODS: We reviewed 160 patients with multiple HCCs who underwent liver resection between July 2003 and December 2018. The risk factors for tumor recurrence were assessed using Cox proportional hazards modeling, and survival was analyzed using the Kaplan-Meier method. RESULTS: In all 160 patients, 133 (83.1%) exceeded the Milan criteria. Total tumor volume (TTV) > 275 cm3 and serum alpha-fetoprotein (AFP) level > 20 ng/mL were associated with disease-free survival. Patients beyond the Milan criteria were grouped into three risk categories: no risk (TTV ≤ 275 cm3 and AFP ≤ 20 ng/mL, n = 39), one risk (either TTV > 275 cm3 or AFP > 20 ng/mL, n = 76), and two risks (TTV > 275 cm3 and AFP > 20 ng/mL, n = 18). No-risk group had comparable disease-free survival (p = 0.269) and overall survival (p = 0.215) to patients who met the Milan criteria. CONCLUSION: Patients with TTV ≤ 275 cm3 and AFP ≤ 20 ng/mL can have good outcomes even exceed the Milan criteria.


Assuntos
Carcinoma Hepatocelular , Hepatectomia , Neoplasias Hepáticas , Carga Tumoral , Humanos , Carcinoma Hepatocelular/cirurgia , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/sangue , Neoplasias Hepáticas/cirurgia , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/sangue , Masculino , Feminino , Pessoa de Meia-Idade , Hepatectomia/métodos , Idoso , Estudos Retrospectivos , alfa-Fetoproteínas/metabolismo , alfa-Fetoproteínas/análise , Fatores de Risco , Recidiva Local de Neoplasia/epidemiologia , Intervalo Livre de Doença , Neoplasias Primárias Múltiplas/cirurgia , Neoplasias Primárias Múltiplas/patologia , Neoplasias Primárias Múltiplas/sangue , Neoplasias Primárias Múltiplas/mortalidade , Adulto
12.
BMC Public Health ; 24(1): 1908, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39014407

RESUMO

OBJECTIVE: The oxidative balance score (OBS) reflects the overall burden of oxidative stress in an individual, with a higher OBS indicating greater antioxidant exposure. This study aimed to explore the association between constipation and OBS. METHODS: Variables were extracted from participants who completed a constipation questionnaire as part of the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2010. The OBS was developed based on dietary and lifestyle factors, encompassing 16 nutrients and 4 lifestyle variables. Weighted logistic regression and restricted cubic spline (RCS) analyses were employed to evaluate the association between OBS and constipation. RESULTS: After adjusting for all covariates, weighted multivariate logistic regression analysis revealed a 4% reduction in the incidence of constipation for each additional unit of OBS (OR: 0.96, 95% CI: 0.95-0.97, p < 0.001). In the OBS subgroup, the risk of constipation significantly decreased compared to that in the lowest quartile (Q2: 0.72, P = 0.024; Q3: 0.59, P < 0.001; Q4: 0.54, P < 0.001). CONCLUSIONS: The present study demonstrated a significant association between constipation and the oxidative balance score (OBS), particularly dietary OBS, and that an increase in OBS may reduce the risk of developing constipation, in which oxidative stress may play an important role. This finding suggested that dietary modification could be an important approach for preventing constipation.


Assuntos
Constipação Intestinal , Inquéritos Nutricionais , Estresse Oxidativo , Humanos , Constipação Intestinal/epidemiologia , Estudos Transversais , Feminino , Masculino , Estresse Oxidativo/fisiologia , Pessoa de Meia-Idade , Adulto , Dieta , Estilo de Vida , Idoso , Inquéritos e Questionários , Estados Unidos/epidemiologia , Modelos Logísticos
13.
Sensors (Basel) ; 24(14)2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39066139

RESUMO

Hemodialysis is achieved by implanting a smart arteriovenous graft (AVG) to build a vascular pathway, but reliability and stability in data transmission cannot be guaranteed. To address this issue, a miniaturized dual-band circularly polarized implantable antenna operating at 1.4 GHz (for energy transmission) and 2.45 GHz (for wireless telemetry), implanted in a wireless arteriovenous graft monitoring device (WAGMD), has been designed. The antenna design incorporates a rectangular serpentine structure on the radiation surface to reduce its volume to 9.144 mm3. Furthermore, matching rectangular slots on the radiation surface and the ground plane enhance the antenna's circular polarization performance. The simulated effective 3 dB axial ratio (AR) bandwidths are 11.43% (1.4 GHz) and 12.65% (2.45 GHz). The simulated peak gains of the antenna are -19.55 dBi and -22.85 dBi at 1.4 GHz and 2.45 GHz, respectively. The designed antenna is implanted in a WAGMD both in the simulation and the experiment. The performance of the system is simulated in homogeneous human tissue models of skin, fat, and muscle layers, as well as a realistic adult male forearm model. The measurement results in a minced pork environment align closely with the simulation results.


Assuntos
Diálise Renal , Tecnologia sem Fio , Diálise Renal/instrumentação , Humanos , Tecnologia sem Fio/instrumentação , Telemetria/instrumentação , Desenho de Equipamento , Próteses e Implantes , Masculino
14.
J Environ Manage ; 355: 120503, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38457894

RESUMO

The global concern regarding the adverse effects of heavy metal pollution in soil has grown significantly. Accurate prediction of heavy metal content in soil is crucial for environmental protection. This study proposes an inversion analysis method for heavy metals (As, Cd, Cr, Cu, Ni, Pb) in soil based on hyperspectral and machine learning algorithms for 21 soil reference materials from multiple provinces in China. On this basis, an integrated learning model called Stacked RF (the base model is XGBoost, LightGBM, CatBoost, and the meta-model is RF) was established to perform soil heavy metal inversion. Specifically, three popular algorithms were initially employed to preprocess the spectral data, then Random Forest (RF) was used to select the best feature bands to reduce the impact of noise, finally Stacking and four basic machine learning algorithms were used to establish comparisons and analysis of inversion model. Compared with traditional machine learning methods, the stacking model showcases enhanced stability and superior accuracy. Research results indicate that machine learning algorithms, especially ensemble learning models, have better inversion effects on heavy metals in soil. Overall, the MF-RF-Stacking model performed best in the inversion of the six heavy metals. The research results will provide a new perspective on the ensemble learning model method for soil heavy metal content inversion using data of hyperspectral characteristic bands collected from soil reference materials.


Assuntos
Metais Pesados , Poluentes do Solo , Solo , Monitoramento Ambiental/métodos , Poluentes do Solo/análise , Metais Pesados/análise , China , Aprendizado de Máquina
15.
J Foot Ankle Surg ; 63(6): 668-671, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38972566

RESUMO

It has been demonstrated in a number of studies that high levels of uric acid can cause crystal deposition in the tendons of the lower extremities, which in turn can impair the Achilles tendon. This study aimed to interpret whether hyperuricemia is relevant with Achilles tendon rupture. Patients diagnosed with Achilles tendon rupture at the same institution between 2013 and 2022 were included in the case group. Healthy subjects who had physical examinations during the same period were included in the control group. Propensity score matching was used to match in a 1:1 ratio. Demographic and clinical characteristics of patients in both groups were compared. Five hundred and fourteen patients were included in the study (ATR=257; Control group=257). The proportion of individuals with hyperuricemia varied significantly between the 2 groups (Achilles tendon rupture group=43.6%; control group=27.6%; p<0.001). The Achilles tendon rupture and hyperuricemia were linked by conditional logistic regression (p<0.001; OR=2.036; 95CI%=1.400-2.961). Compared with healthy subjects, patients with hyperuricemia have a higher risk of Achilles tendon rupture. Further studies are required to verify the effects of hyperuricemia and monosodium urate crystals on Achilles tendon structure.


Assuntos
Tendão do Calcâneo , Hiperuricemia , Traumatismos dos Tendões , Humanos , Tendão do Calcâneo/lesões , Hiperuricemia/complicações , Feminino , Masculino , Estudos de Casos e Controles , Pessoa de Meia-Idade , Ruptura , Adulto , Fatores de Risco , Pontuação de Propensão , Estudos Retrospectivos , Idoso
16.
Angew Chem Int Ed Engl ; 63(2): e202313985, 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38014418

RESUMO

3-Deoxy-d-manno-oct-2-ulosonic acid (Kdo) is an eight-carbon monosaccharide found widely in bacterial lipopolysaccharides (LPSs) and capsule polysaccharides (CPSs). We developed an indirect method for the stereoselective synthesis of α-Kdo glycosides with a C3-p-tolylthio-substituted Kdo phosphite donor. The presence of the p-tolylthio group enhanced the reactivity, suppressed the formation of elimination by-products (2,3-enes), and provided complete α-stereocontrol. A variety of Kdo α-glycosides were synthesized by our method in excellent yields (up to 98 %). After glycosylation, the p-tolylthio group can be efficiently removed by free-radical reduction. Subsequently, the orthogonality of the phosphite donor and thioglycoside donor was demonstrated by the one-pot synthesis of a trisaccharide in Helicobacter pylori and Neisseria meningitidis LPS. Moreover, an efficient total synthesis route to the challenging 4,5-branched Kdo trisaccharide in LPSs from several A. baumannii strains was highlighted. To demonstrate the high reactivity of our approach further, the highly crowded 4,5,7,8-branched Kdo pentasaccharide was synthesized as a model molecule for the first time. Additionally, the reaction mechanism was investigated by DFT calculations.


Assuntos
Glicosídeos , Fosfitos , Oligossacarídeos , Açúcares Ácidos , Lipopolissacarídeos , Trissacarídeos
17.
Opt Lett ; 48(22): 5883-5886, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37966743

RESUMO

A photonic-assisted scheme to generate radar compound coherent jamming signals based on a dual-parallel Mach-Zehnder modulator (DP-MZM) is proposed and experimentally demonstrated. The received linear frequency-modulated (LFM) signal is interrupted sampled and comb spectrum modulated by a DP-MZM. After photoelectric conversion, the compound coherent jamming signal, which combines the comb spectrum modulation jamming (CSMJ) and interrupted sampling repeater jamming (ISRJ), is generated. In the experiment, the generated coherent jamming signals have a 1-GHz bandwidth centered at 8 GHz and 18 GHz, respectively. The tunability of the frequency interval for CSMJ, the duty cycle, and the sampling frequency for ISRJ are verified. After pulse compression (PC), 10 false target groups are evenly distributed over a radial distance of 120 m, and the total number of false targets reaches to 50. The jamming effectiveness in radar imaging is also demonstrated. To the best of our knowledge, photonic-assisted CSMJ and ISRJ compound jamming generation is proposed for the first time. The proposed scheme is compact, wideband, and tunable, which shows a good potential application in the future electronic warfare system.

18.
Microb Ecol ; 86(4): 2330-2343, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37222804

RESUMO

The surface water is an important habitat for freshwater microorganisms, but there is a lack of understanding of the pattern of microbial diversity and structure in stream continuums of small subtropical forest watersheds. Therefore, this study aimed to understand the variations in microbial diversity and community structure along stream orders (1-5) in the small subtropical forest catchments of the Wuyi Mountains. Using GIS software, 20 streams were chosen and classified into 5 orders. Illumina sequencing was used to analyze the dynamics of microbial communities, along with stream orders and hydro-chemical properties of stream water were also determined. Our results indicated that the bacterial and fungal richness (ACE index) was higher in low-order (1 and 2 orders) streams than in high-order (3, 4, and 5 orders) streams, with the highest value in the order 2 streams (P < 0.05). The water temperature and dissolved oxygen were positively correlated with fungal richness (P < 0.05). The bacterial rare taxa had a significant correlation with the abundance taxa (P < 0.05). The relative abundances of Bacteroidetes, Actinobacteria, and Chytridiomycota microbial phyla were significantly different among different order streams (P < 0.05). Using the neutral community model, we found that the fungal community structure was significantly shaped by hydro-chemical properties, while the bacterial community structure was largely regulated by stochastic processes. Our findings suggest that variations in microbial community structure in subtropical headwaters are largely shaped by the water temperature and dissolved oxygen.


Assuntos
Bactérias , Microbiota , Bactérias/genética , Água Doce/microbiologia , Água/química , Oxigênio
19.
Inorg Chem ; 62(33): 13649-13661, 2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37599581

RESUMO

The development of a gas sensor capable of detecting ammonia with high selectivity and rapid response at room temperature has consistently posed a formidable challenge. To address this issue, the present study utilized a one-step solvothermal method to co-assemble α-Fe2O3 and SnO2 by evenly covering SnO2 nanoparticles on the surface of α-Fe2O3. By controlling the morphology and Fe/Sn mole ratio of the composite, the as-prepared sample exhibits high-performance detection of NH3. At room temperature conditions, a gas sensor composed of α-Fe2O3@3%SnO2 demonstrates a rapid response time of 14 s and a notable sensitivity of 83.9% when detecting 100 ppm ammonia. Experiments and density functional theory (DFT) calculations suggest that the adsorption capacity of α-Fe2O3 to ammonia is enhanced by the surface effect provided by SnO2. Meanwhile, the existence of SnO2 tailors the pore structure and effective surface area of α-Fe2O3, creating multiple channels for the diffusion and adsorption of ammonia molecules. Additionally, an N-N heterostructure is formed between α-Fe2O3 and SnO2, which enhances the potential energy barrier and improves the ammonia sensing performance. Demonstration experiments have proved that the sensor shows significant advantages over commercial sensors in the process of ammonia detection in agricultural facilities. This work provides new insights into the perspectives on ammonia detection at room temperature.

20.
Environ Res ; 232: 116389, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37302742

RESUMO

Microplastics (MPs) in farming soils can have a substantial impact on soil ecology and agricultural productivity, as well as affecting human health and the food chain cycle. As a result, it is vital to study MPs detection technologies that are rapid, efficient, and accurate in agriculture soils. This study investigated the classification and detection of MPs using hyperspectral imaging (HSI) technology and a machine learning methodology. To begin, the hyperspectral data was preprocessed using SG convolution smoothing and Z-score normalization. Second, the feature variables were extracted from the preprocessed spectral data using bootstrapping soft shrinkage, model adaptive space shrinkage, principal component analysis, isometric mapping (Isomap), genetic algorithm, successive projections algorithm (SPA), and uninformative variable elimination. Finally, three support vector machine (SVM), back propagation neural network (BPNN), and one-dimensional convolutional neural network (1D-CNN) models were developed to classify and detect three microplastic polymers: polyethylene, polypropylene, and polyvinyl chloride, as well as their combinations. According to the experimental results, the best approaches based on three models were Isomap-SVM, Isomap-BPNN, and SPA-1D-CNN. Among them, the accuracy, precision, recall and F1_score of Isomap-SVM were 0.9385, 0.9433, 0.9385 and 0.9388, respectively. The accuracy, precision, recall and F1_score of Isomap-BPNN were 0.9414, 0.9427, 0.9414 and 0.9414, respectively, while the accuracy, precision, recall and F1_score of SPA-1D-CNN were 0.9500, 0.9515, 0.9500 and 0.9500, respectively. When their classification accuracy was compared, SPA-1D-CNN had the best classification performance, with a classification accuracy of 0.9500. The findings of this study shown that the SPA-1D-CNN based on HSI technology can efficiently and accurately identify MPs in farmland soils, providing theoretical backing as well as technical means for real-time detection of MPs in farmland soils.


Assuntos
Microplásticos , Plásticos , Humanos , Imageamento Hiperespectral , Solo , Fazendas , Tecnologia
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