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1.
Nat Prod Res ; : 1-7, 2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36622881

RESUMO

Two new farnesane sesquiterpenoid glycosides, rubusdelosides A and B (1 and 4), together with five known farnesane sesquiterpenoids (2, 3, and 5-7), and two known meroterpenoids (8 and 9), were isolated from water extract of the herbs of R. delavayi. Their structures were identified by the comprehensive analyses of physicochemical properties and spectroscopic data (NMR and HR-ESI-MS). Compounds 1-8 showed moderate in vivo anti-T. spiralis activities.

2.
J Med Internet Res ; 25: e39128, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36596239

RESUMO

BACKGROUND: Mobile mindfulness meditation (MMM) is a mindfulness meditation intervention implemented using mobile devices such as smartphones and apps. MMM has been used to help manage the mental health of university students. OBJECTIVE: This study aims to evaluate the effectiveness of MMM on the mental health of university students in the areas of stress, anxiety, depression, mindfulness, well-being, and resilience. METHODS: We conducted a systematic review and meta-analysis of the effectiveness of MMM on the mental health of university students. This study followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. An electronic literature search was performed on PubMed, Web of Science, EBSCO, Cochrane Library, and Embase databases, from inception to July 16, 2021. This study was conducted to identify studies that reported the effects of MMM on the primary outcomes including stress, anxiety, and depression, and on the secondary outcomes including mindfulness, well-being, and resilience. Two reviewers retrieved articles, evaluated quality, and extracted data independently. The methodological quality of the selected studies was determined using the Cochrane criteria for risk-of-bias assessment. Standardized mean differences (SMDs) for continuous outcomes and risk ratios for dichotomous outcomes were calculated. Sensitivity analyses and subgroup analyses were performed for results with high heterogeneity. The RevMan version 5.3 was used to perform meta-analysis. RESULTS: A total of 10 studies, including 958 university students, were selected for this meta-analysis. Results of the primary outcome showed that the MMM groups were more effective than the control groups in decreasing stress (SMD -0.41, 95% CI -0.59 to -0.23; P<.001) and alleviating anxiety (SMD -0.29, 95% CI -0.50 to -0.09; P=.004). However, there was no difference between the MMM groups and the control groups in depression (SMD -0.14, 95% CI -0.30 to 0.03; P=.11). The use of either waitlist control or traditional face-to-face intervention in the control group was identified as the source of heterogeneity. Specifically, the waitlist control subgroup (SMD -0.33, 95% CI -0.53 to -0.13; P=.002) was superior when compared with the face-to-face subgroup (SMD 0.29, 95% CI -0.01 to 0.59; P=.06). Results of the secondary outcome showed that the MMM groups were more effective than the control groups in enhancing well-being (SMD 0.30, 95% CI 0.11-0.50; P=.003) and improving mindfulness (SMD 2.66, 95% CI 0.77-4.55; P=.006). Whether commercial sponsorship was obtained was considered as the source of heterogeneity. The "without company support" group (SMD 17.60, 95% CI 11.32-23.87; P<.001) was superior to the "with company support" group (SMD 1.17, 95% CI -0.82 to 3.15; P=.25) in raising the level of mindfulness. However, there was no difference between the MMM and control groups in resilience (SMD -0.06, 95% CI -0.26 to 0.15; P=.59). The evidence level of the results from the 10 studies was determined to be moderate to low. CONCLUSIONS: MMM was an effective method to reduce stress and anxiety, and to increase the well-being and mindfulness of university students. However, further studies are needed to confirm our findings. TRIAL REGISTRATION: PROSPERO International Prospective Register of Systematic Reviews CRD42022303585; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=303585.


Assuntos
Meditação , Atenção Plena , Humanos , Atenção Plena/métodos , Saúde Mental , Depressão/terapia , Universidades , Estudantes
3.
Curr Microbiol ; 80(2): 70, 2023 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-36609874

RESUMO

Microbes use both organic and inorganic compounds as electron donors, with different electronic potentials, to produce energy required for growth in environments. Conventional studies on the effects of different electron donors on microbial community has been extensively studied with a set cathode potential. However, it remains under-researched how a microbial community response to the different redox potentials in different environments. Here, we incubated a lake sediment in a single-chamber reactor equipped with three working electrodes, i.e., with potentials of - 0.29 V, - 0.05 V versus standard hydrogen electrode and open-circuit, respectively. Results reveal that the structure of bacterial communities was highly similar for all closed-circuit electrodes (- 0.29 V, - 0.05 V), while differing significantly from those on open-circuit electrodes. We also show that specific bacteria were preferentially enriched by different electrode potentials, i.e., Pseudomonas and Rhodobacter preferentially grew on - 0.05 V and - 0.29 V cathode potentials, Azospirillum and Bosea preferentially grew on - 0.05 V; while Ferrovibrio, Hydrogenophaga, Delftia, and Sphingobium preferentially grew on - 0.29 V. In addition, microorganisms selectively enriched on open-circuit electrodes possess higher connectivity and closer relationship than microorganisms selectively enriched on closed-circuit electrode.


Assuntos
Fontes de Energia Bioelétrica , Microbiota , Fontes de Energia Bioelétrica/microbiologia , Bactérias/genética , Eletrodos
4.
World J Pediatr ; 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36607547

RESUMO

BACKGROUND: Due to the broad application of next-generation sequencing, the molecular diagnosis of genetic disorders in pediatric neurology is no longer an unachievable goal. However, treatments for neurological genetic disorders in children remain primarily symptomatic. On the other hand, with the continuous evolution of therapeutic viral vectors, gene therapy is becoming a clinical reality. From this perspective, we wrote this review to illustrate the current state regarding viral-mediated gene therapy in childhood neurological disorders. DATA SOURCES: We searched databases, including PubMed and Google Scholar, using the keywords "adenovirus vector," "lentivirus vector," and "AAV" for gene therapy, and "immunoreaction induced by gene therapy vectors," "administration routes of gene therapy vectors," and "gene therapy" with "NCL," "SMA," "DMD," "congenital myopathy," "MPS" "leukodystrophy," or "pediatric metabolic disorders". We also screened the database of ClinicalTrials.gov using the keywords "gene therapy for children" and then filtered the results with the ones aimed at neurological disorders. The time range of the search procedure was from the inception of the databases to the present. RESULTS: We presented the characteristics of commonly used viral vectors for gene therapy for pediatric neurological disorders and summarized their merits and drawbacks, the administration routes of each vector, the research progress, and the clinical application status of viral-mediated gene therapy on pediatric neurological disorders. CONCLUSIONS: Viral-mediated gene therapy is on the brink of broad clinical application. Viral-mediated gene therapy will dramatically change the treatment pattern of childhood neurological disorders, and many children with incurable diseases will meet the dawn of a cure. Nevertheless, the vectors must be optimized for better safety and efficacy.

6.
Anal Bioanal Chem ; 2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36705731

RESUMO

Because of the pivotal point of Marchantia polymorpha (M. polymorpha) in plant evolution, its auxin (mainly indole-3-acetic acid, IAA) levels could provide useful evidence for the study of the evolution of IAA. However, M. polymorpha could not be easily pretreated for electrochemical detection because they are at the entry level of land plants. Herein, we designed a three-dimensional (3D)-printed analytical device for seamless integration of sample treatment and electrochemical detection. Specifically, the electrochemical cell could be used as a mortar in which a tiny plant sample could be ground with a 3D-printed pestle, followed by mixing with the buffer solution under vibration for electrochemical detection of IAA with a disposable working electrode at the bottom of the cell. Using our strategy, the limits of quantification could reach 0.05 µmol L-1 after optimization of parameters. We were able to demonstrate that IAA in different tissues of wild-type and mutant M. polymorpha could be successfully differentiated after they were treated with the 3D-printed analytical device. The obtained results were comparable to the samples blended with zirconium beads while the differences of IAA levels in different tissues of M. polymorpha agreed well with previous reports. This study suggested the potential of sample treatment integrated with electrochemical detection for analysis of IAA using the 3D printing techniques and their possible applications in the research of plants and other fields.

7.
World J Clin Cases ; 11(1): 135-142, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36687199

RESUMO

BACKGROUND: Polyneuropathy organomegaly endocrinopathy M-protein and skin changes (POEMS) syndrome is a rare paraneoplastic syndrome caused by a potential plasma cell tumor. The clinical manifestations of POEMS syndrome are diverse. Due to the insidious onset and lack of specific early-stage manifestations, POEMS syndrome is easily misdiagnosed or never diagnosed, leading to delayed treatment. Neurological symptoms are usually the first clinical manifestation, while ascites is a rare symptom in patients with POEMS syndrome. CASE SUMMARY: A female patient presented with unexplained ascites as an initial symptom, which is a rare early-stage manifestation of the condition. After 1 year, the patient gradually developed progressive renal impairment, anemia, polyserosal effusion, edema, swollen lymph nodes on the neck, armpits, and groin, and decreased muscle strength of the lower extremities. The patient was eventually diagnosed with POEMS syndrome after multidisciplinary team discussion. Treatment comprised bortezomib + dexamethasone, continuous renal replacement therapy, chest and abdominal closed drainage, transfusions of erythrocytes and platelets, and other symptomatic and supportive treatments. The patient's condition initially improved after treatment. However, then her symptoms worsened, and she succumbed to the illness and died. CONCLUSION: Ascites is a potential early manifestation of POEMS syndrome, and this diagnosis should be considered for patients with unexplained ascites. Furthermore, multidisciplinary team discussion is helpful in diagnosing POEMS syndrome.

8.
J Agric Food Chem ; 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36696251

RESUMO

Succinate dehydrogenase (SDH, EC 1.3.5.1, also known as complex II) has been recognized as one of the most promising targets of fungicides. Here, based on the binding mode of pydiflumetofen with SDH, the carbon-carbon double bond was introduced into the chemical of pydiflumetofen and then produced the target compounds 6a-6o. The enzymatic inhibitory activity and structure-activity relationship (SAR) study showed that the 2-position and 4-position in terminal benzene were positive to increasing activity. Furthermore, fungicidal activity results in greenhouses indicated that compound 6o showed good control effects against wheat powdery mildew (WPM), cucumber powdery mildew (CPM), and southern corn rust (SCR), showing its broad-spectrum property. Especially, compound 6o exhibited 95 and 75% control effects against CPM and SCR at 6.25 mg/L, respectively, which are better than pydiflumetofen (80% control effects against CPM and 15% against SCR), indicating its potency that is worthy of further development.

9.
Microorganisms ; 11(1)2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36677443

RESUMO

Oil reservoirs are one of the most important deep subsurface biospheres. They are inhabited by diverse microorganisms including bacteria and archaea with diverse metabolic activities. Although recent studies have investigated the microbial communities in oil reservoirs at large geographic scales, it is still not clear how the microbial communities assemble, as the variation in the environment may be confounded with geographic distance. In this work, the microbial communities in oil reservoirs from the same oil field were identified at a localized geographic scale. We found that although the injected water contained diverse exogenous microorganisms, this had little effect on the microbial composition of the produced water. The Neutral Community Model analysis showed that both bacterial and archaeal communities are dispersal limited even at a localized scale. Further analysis showed that both pH and nitrate concentrations drive the assembly of bacterial communities, of which nitrate negatively correlated with bacterial alpha diversity and pH differences positively correlated with the dissimilarity of bacterial communities. In contrast, the physiochemical parameters had little effect on archaeal communities at the localized scale. Our results suggest that the assembly of microbial communities in oil reservoirs is scale- and taxonomy-dependent. Our work provides a comprehensive analysis of microbial communities in oil reservoirs at a localized geographic scale, which improves the understanding of the assembly of the microbial communities in oil reservoirs.

10.
Neural Regen Res ; 18(3): 683-688, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36018194

RESUMO

Percutaneous electrical nerve stimulation of an injured nerve can promote and accelerate peripheral nerve regeneration and improve function. When performing acupuncture and moxibustion, locating the injured nerve using ultrasound before percutaneous nerve stimulation can help prevent further injury to an already injured nerve. However, stimulation parameters have not been standardized. In this study, we constructed a multi-layer human forearm model using finite element modeling. Taking current density and activated function as optimization indicators, the optimal percutaneous nerve stimulation parameters were established. The optimal parameters were parallel placement located 3 cm apart with the injury site at the midpoint between the needles. To validate the efficacy of this regimen, we performed a randomized controlled trial in 23 patients with median nerve transection who underwent neurorrhaphy. Patients who received conventional rehabilitation combined with percutaneous electrical nerve stimulation experienced greater improvement in sensory function, motor function, and grip strength than those who received conventional rehabilitation combined with transcutaneous electrical nerve stimulation. These findings suggest that the percutaneous electrical nerve stimulation regimen established in this study can improve global median nerve function in patients with median nerve transection.

11.
Int J Psychophysiol ; 184: 1-11, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36481460

RESUMO

BACKGROUNDS: Depression is the most common mental disorder in the world. Sleep deprivation (SD) is a well-known antidepressant. Several recombination protocols (including medications, bright light treatment [BLT], cognitive-behavioral therapy, sleep phrase advance/sleep phrase delay [SPA/SPD], and repetitive transcranial magnetic stimulation [rTMS]) have been developed to improve and maintain the effect of SD. However, relapse after recovery sleep has been reported, and different recombination protocols result in different outcomes. METHODS: The Embase, Cochrane, PubMed, CBM, Web of Science, and CINAHL databases were searched for clinical trials assessing depression and SD. Three independent reviewers classified forty-three abstracts. The Hamilton Depression Rating Scale was used to assess the outcomes. RESULTS: Compared with existing therapy, patients receiving SD displayed a significant improvement in clinician-rated depressive symptoms (MD -1.48 [95 % CI -2.60, -0.37], p < 0.05). A significant decrease was found in the subgroups of SD plus SPA/SPD (odds ratio 3.90 [95 % CI 1.66, 9.17], p < 0.05), total sleep deprivation[TSD] plus BLT (MD -3.28 [95 % CI -5.06, -1.50], p < 0.05), and partial sleep deprivation[PSD] plus rTMS (MD -7.94 [95 % CI -11.44, -4.45], p < 0.05). No significant differences were observed in the other subgroups. CONCLUSIONS: Adding SD to existing therapies showed a positive outcome in improving depression treatment, which provides evidence for the use of SD in treating depression. Further studies are needed to determine the precise effects of SD plus other interventions.


Assuntos
Depressão , Privação do Sono , Humanos , Privação do Sono/terapia , Depressão/tratamento farmacológico , Resultado do Tratamento , Ensaios Clínicos Controlados Aleatórios como Assunto , Antidepressivos
13.
J Agric Food Chem ; 71(1): 615-625, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36537359

RESUMO

Optimized source-sink interactions are determinants of both rice yield and quality. However, most source genes have not been well studied in rice, a major grain crop. In this study, OsBMY4 and OsISA3, the key ß-amylase and debranching enzymes that control transient starch degradation in rice leaves, were co-overexpressed in rice in order to accelerate starch degradation efficiency and increase the sugar supply for sink organs. Systematic analyses of the transgenic rice indicated that co-overexpression of OsBMY4 and OsISA3 not only promoted rice yield and quality, but also improved seed germination and stress tolerance. Moreover, since the OsBMY4 gene has not been characterized, we generated osbmy4 mutants using CRIPSR/Cas9 gene editing, which helped to reveal the roles of ß-amylase in rice yield and quality. This study demonstrated that specific modulation of the expression of some key source genes improves the source-sink balance and leads to improvements in multiple key traits of rice seeds.


Assuntos
Oryza , beta-Amilase , Oryza/genética , Oryza/metabolismo , beta-Amilase/genética , Sementes/genética , Sementes/metabolismo , Grão Comestível/metabolismo , Amido/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
14.
J Biol Chem ; : 102765, 2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36470423

RESUMO

Hyperlipidemia characterized by high blood levels of free fatty acids (FFA) is important for the progression of inflammatory cardiovascular diseases. Integrin ß1 is a transmembrane receptor that drives various cellular functions, including differentiation, migration, and phagocytosis. However, the underlying mechanisms modifying integrin ß1 protein and activity in mediating monocyte/macrophage adhesion to endothelium remain poorly understood. In this study, we demonstrated that integrin ß1 protein underwent S-nitrosylation in response to nitrosative stress in macrophages. To examine the effect of elevated levels of FFA on the modulation of integrin ß1 expression, we treated the macrophages with a combination of oleic acid and palmitic acid (2:1) and found that FFA activated inducible nitric oxide synthase (iNOS)/nitric oxide (NO) and increased the integrin ß1 protein level without altering the mRNA level. FFA promoted integrin ß1 S-nitrosylation via iNOS/NO and prevented its degradation by decreasing binding to E3 ubiquitin ligase c-Cbl. Furthermore, we found that increased integrin α4ß1 heterodimerization resulted in monocyte/macrophage adhesion to endothelium. In conclusion, these results provided novel evidence that FFA-stimulated NO stabilizes integrin ß1 via S-nitrosylation, favoring integrin α4ß1 ligation to promote vascular inflammation.

15.
J Bionic Eng ; : 1-22, 2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36466725

RESUMO

Whale optimization algorithm (WOA) tends to fall into the local optimum and fails to converge quickly in solving complex problems. To address the shortcomings, an improved WOA (QGBWOA) is proposed in this work. First, quasi-opposition-based learning is introduced to enhance the ability of WOA to search for optimal solutions. Second, a Gaussian barebone mechanism is embedded to promote diversity and expand the scope of the solution space in WOA. To verify the advantages of QGBWOA, comparison experiments between QGBWOA and its comparison peers were carried out on CEC 2014 with dimensions 10, 30, 50, and 100 and on CEC 2020 test with dimension 30. Furthermore, the performance results were tested using Wilcoxon signed-rank (WS), Friedman test, and post hoc statistical tests for statistical analysis. Convergence accuracy and speed are remarkably improved, as shown by experimental results. Finally, feature selection and multi-threshold image segmentation applications are demonstrated to validate the ability of QGBWOA to solve complex real-world problems. QGBWOA proves its superiority over compared algorithms in feature selection and multi-threshold image segmentation by performing several evaluation metrics. Supplementary Information: The online version contains supplementary material available at 10.1007/s42235-022-00297-8.

16.
J Bionic Eng ; : 1-20, 2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36466726

RESUMO

Pulmonary Hypertension (PH) is a global health problem that affects about 1% of the global population. Animal models of PH play a vital role in unraveling the pathophysiological mechanisms of the disease. The present study proposes a Kernel Extreme Learning Machine (KELM) model based on an improved Whale Optimization Algorithm (WOA) for predicting PH mouse models. The experimental results showed that the selected blood indicators, including Haemoglobin (HGB), Hematocrit (HCT), Mean, Platelet Volume (MPV), Platelet distribution width (PDW), and Platelet-Large Cell Ratio (P-LCR), were essential for identifying PH mouse models using the feature selection method proposed in this paper. Remarkably, the method achieved 100.0% accuracy and 100.0% specificity in classification, demonstrating that our method has great potential to be used for evaluating and identifying mouse PH models.

17.
Front Pediatr ; 10: 1022865, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36467472

RESUMO

Background: Blood pressure (BP) exhibits seasonal variation with lower levels at higher temperatures and vice versa. This phenomenon affects both sexes and all age groups. So far, only a few research studies have investigated this condition in adolescents and none of them were based on hypertensive population or ever applied ambulatory blood pressure monitor (ABPM). Therefore, we carried out the first study that used ABPM to record seasonal variation of blood pressure in hypertensive adolescents. Methods: From March 2018 to February 2019, 649 ABPMs from hypertensive adolescents between 13 and 17 years who were referred to wear an ABPM device in Beijing and Baoding were extracted. Seasonal change in ambulatory BP value, dipping status, and prevalence of different BP phenotypes were analyzed and compared. Results: Mean age of participants was 14.9 ± 1.5 years and 65.8% of them were boys. Of the participants, 75.3% met the criteria of overweight or obesity. From summer to winter, average 24-hour, day-time, and night-time BP showed significant rise, which was 9.8/2.8, 9.8/3.0, and 10.9/3.4 mmHg, respectively. This seasonal effect on BP was not dependent on the obesity degree. In addition, higher prevalence of nondippers and risers existed in winter while white coat hypertension was more frequent in warmer seasons. Conclusion: Hypertensive adolescents showed evident seasonal change in their ABPM results, which was featured by elevated BP level and more frequent abnormal dipping patterns in winter. On the contrary, higher prevalence of white coat hypertension was found in warmer seasons. Physicians should take seasonal variation into consideration when managing adolescent hypertension.

18.
J Thorac Imaging ; 2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36469852

RESUMO

OBJECTIVES: To investigate the optimal measurement site of coronary-computed tomography angiography-derived fractional flow reserve (FFRCT) for the assessment of coronary artery disease (CAD) in the whole clinical routine practice. MATERIALS AND METHODS: This retrospective multicenter study included 396 CAD patients who underwent coronary-computed tomography angiography, FFRCT, and invasive FFR. FFRCT was measured at 1 cm (FFRCT-1 cm), 2 cm (FFRCT-2 cm), 3 cm (FFRCT-3 cm), and 4 cm (FFRCT-4 cm) distal to coronary stenosis, respectively. FFRCT and invasive FFR ≤0.80 were defined as lesion-specific ischemia. The diagnostic performance of FFRCT to detect ischemia was obtained using invasive FFR as the reference standard. Reduced invasive coronary angiography rate and revascularization efficiency were calculated. After a median follow-up of 35 months in 267 patients for major adverse cardiovascular events (MACE), Cox hazard proportional models were performed with FFRCT values at each measurement site. RESULTS: For discriminating lesion-specific ischemia, the areas under the curve of FFRCT-1 cm (0.91) as well as FFRCT-2 cm (0.91) were higher than those of FFRCT-3 cm (0.89) and FFRCT-4 cm (0.88), respectively (all P<0.05). The higher reduced invasive coronary angiography rate (81.6%) was found at FFRCT-1 cm than FFRCT-2 cm (81.6% vs. 62.6%, P<0.05). Revascularization efficiency did not differ between FFRCT-1 cm and FFRCT-2 cm (80.8% vs. 65.5%, P=0.019). In 12.4% (33/267) MACE occurred and only values of FFRCT-2 cm were independently predictive of MACE (hazard ratio: 0.957 [95% CI: 0.925-0.989]; P=0.010). CONCLUSIONS: This study indicates FFRCT-2 cm is the optimal measurement site with superior diagnostic performance and independent prognostic role.

19.
Langmuir ; 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36453942

RESUMO

As a new type of carbon material, graphene oxide aerogel (GA) is widely used in catalysis due to its porous structure, high-efficiency adsorption, and superb conductivity. In this study, GA was prepared into a dense coating layer surrounding ZnCo2O4/ZnO particles to form a composite GA-ZnCo2O4/ZnO by means of a hydrothermal, blast drying, and vacuum-freeze-drying approach applied to catalyze the thermal decomposition of ammonium perchlorate (AP). The physicochemical properties of the obtained GA-ZnCo2O4/ZnO were characterized by different analytical methods. Scanning electron microscopy (SEM) analysis exhibited that GA is coated on the surface of ZnCo2O4/ZnO, forming a dense layer. Brunner Emmet Teller (BET) measurement results show that GA-ZnCo2O4/ZnO has a smooth macropore distribution curve and a larger specific surface area. Moreover, The catalytic effect investigation on AP with GA-ZnCo2O4/ZnO: the high temperature decomposition (HTD) peak temperature of AP in the presence of 5 wt % GA-ZnCo2O4/ZnO was reduced from 441 to 294 °C, and the exotherm of AP was expanded from 205 to 1275 J/g at a heating rate of 15 °C/min. Through the calculation, GA-ZnCo2O4/ZnO makes the activation energy and Gibbs free energy of the AP pyrolysis lower so that the reaction is easier to occur. Thermogravimetric-mass (TG-MS) spectrometry revealed that during thermal decomposition of AP, GA-ZnCo2O4/ZnO leveraged the synergistic catalysis of ZnCo2O4/ZnO and GA that boosted the flow of electrons from ClO4- to O2 and increased the absorption of the gas product to accelerate the AP pyrolysis. These results provided a facile strategy to prepare GA-based composite catalysts with extraordinary application prospects in the domain of solid propellants.

20.
Proc Natl Acad Sci U S A ; 119(49): e2215990119, 2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36454763

RESUMO

Recent characterization of the obligate episymbiont Saccharibacteria (TM7) belonging to the candidate phyla radiation (CPR) has expanded the extent of microbial diversity. However, the episymbiotic lifestyle of TM7 is still underexploited due to the deficiency of cultivated representatives. Here, we describe gene-targeted TM7 cultivation guided by repurposing epicPCR (emulsion, paired isolation, and concatenation PCR) to capture in situ TM7‒host associations. Using this method, we obtained a novel Saccharibacteria isolate TM7i and its host Leucobacter aridicollis J1 from Cicadae Periostracum, the castoff shell of cicada. Genomic analyses and microscopic characterizations revealed that TM7i could bind to J1 through twitching-like motility mediated by type IV pili (T4P). We further showed that the inhibition of T4P extrusion suppressed the motility and host adherence of TM7i, resulting in its reduced growth. However, the inactivation of T4P had little effect on the growth of TM7i that had already adhered to J1, suggesting the essential role of T4P in host recognition by TM7i. By capturing CPR‒host association and elaborating the T4P-dependent episymbiotic association mechanism, our studies shed light on the distinct yet widespread lifestyle of CPR bacteria.


Assuntos
Actinomycetales , Fímbrias Bacterianas , Fímbrias Bacterianas/genética , Bactérias , Reação em Cadeia da Polimerase , Genômica
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