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1.
J Am Chem Soc ; 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38838264

RESUMO

Chiral atomically precise metal clusters, known for their remarkable chiroptical properties, hold great potential for applications in chirality recognition. However, advancements in this field have been constrained by the limited exploration of host-guest chemistry, involving metal clusters. This study reports the synthesis of a chiral Cu16(C2B10H10S2)8 (denoted as Cu16@CB8, where C2B10H12S2H2 = 9,12-(HS)2-1,2-closo-carborane) cluster by an achiral carboranylthiolate ligand. The chiral R-/S-Cu16@CB8 cluster features chiral cavities reminiscent of cyclodextrins, which are surrounded by carborane clusters, yet they crystallize in a racemate. These cyclodextrin-like cavities demonstrated the specific recognition of amino acids, as indicated by the responsive output of circular dichroism and circularly polarized luminescence signals of Cu16 moieties of the Cu16@CB8 cluster. Notably, a quantitative chiroptical analysis of amino acids in a short time and a concomitant deracemization of Cu16@CB8 were achieved. Density functional tight-binding molecular dynamics simulation and noncovalent interaction analysis further unraveled the great importance of the cavities and binding sites for chiral recognition. Dipeptide, tripeptide, and polypeptide containing the corresponding amino acids (Cys, Arg, or His residues) display the same chiral recognition, showing the generality of this approach. The functional synergy of dual clusters, comprising carborane and metal clusters, is for the first time demonstrated in the Cu16@CB8 cluster, resulting in the valuable quantification of the enantiomeric excess (ee) value of amino acids. This work opens a new avenue for chirality sensors based on chiral metal clusters with unique chiroptical properties and inspires the development of carborane clusters in host-guest chemistry.

2.
Muscle Nerve ; 67(5): 417-426, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36878493

RESUMO

INTRODUCTION/AIMS: Oxaliplatin is a commonly used platinum chemotherapy drug, whereas peripheral neurotoxicity is a widely observed adverse reaction lacking a satisfactory therapeutic strategy. Different adenosine receptors underlying the common neuropathic phenotype play different roles through varied pathophysiological mechanisms. In this study, we investigated the role of adenosine receptor A1 (A1R) in oxaliplatin-induced neuropathic pain and its potential use in an effective therapeutic strategy. METHODS: We established an oxaliplatin-induced neuropathic pain model simulating the mode of chemotherapy administration and observed the related neuropathic behavioral phenotype and implicated mechanisms. RESULTS: Five weekly injections of oxaliplatin for 2 weeks induced a severe and persistent neuropathic pain phenotype in mice. A1R expression in the spinal dorsal horn decreased during this process. Pharmacological intervention against A1R verified its importance in this process. Mechanistically, the loss of A1R expression was mainly attributed to its decreased expression in astrocytes. Consistent with the pharmacological results, the oxaliplatin-induced neuropathic pain phenotype was blocked by specific therapeutic interventions of A1R in astrocytes via lentiviral vectors, and the expression of glutamate metabolism-related proteins was upregulated. Neuropathic pain can be alleviated by pharmacological or astrocytic interventions via this pathway. DISCUSSION: These data reveal a specific adenosine receptor signaling pathway involved in oxaliplatin-induced peripheral neuropathic pain, which is related to the suppression of the astrocyte A1R signaling pathway. This may provide new opportunities for the treatment and management of neuropathic pain observed during oxaliplatin chemotherapy.


Assuntos
Astrócitos , Neuralgia , Ratos , Camundongos , Animais , Oxaliplatina/toxicidade , Astrócitos/metabolismo , Roedores/metabolismo , Ratos Sprague-Dawley , Hiperalgesia , Neuralgia/induzido quimicamente , Neuralgia/tratamento farmacológico , Receptor A1 de Adenosina/metabolismo , Receptor A1 de Adenosina/uso terapêutico
3.
Acta Pharmacol Sin ; 44(7): 1464-1474, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36807412

RESUMO

Proteasomes are overexpressed in multiple myeloma (MM) and proteasomal inhibitors (PIs) have been widely used for the treatment of MM. PIs are reported to induce MM cell apoptosis but impair necroptosis. In the present study, we found that PIs MG132 and bortezomib induce MM cell pyroptosis, a novel type of cell death, in a GSDME-dependent manner. Lack of GSDME totally blocks PI-induced pyroptosis. Interestingly, we found that Caspase-3/6/7/9 are all involved in pyroptosis triggered by PIs because the specific inhibitor of each caspase ablates GSDME activation. PIs markedly reduce mitochondrial membrane potential. Moreover, PIs disrupt the interaction of Bcl-2 and BAX, induce cytochrome c release from mitochondria to cytosol and activate GSDME. Furthermore, we found that overexpression of an N-terminal portion of GSDME suffices to release cytochrome c from mitochondria and to activate Caspase-3/9, suggesting N-GSDME might penetrate the mitochondrial membrane. Consistent with Bcl-2 inhibition, BAX can induce MM cell pyroptosis in a GSDME-dependent manner. In accordance with these findings, inhibition of Bcl-2 synergizes with PIs to induce MM cell pyroptosis. Therefore, the present study indicates that PIs trigger MM cell pyroptosis via the mitochondrial BAX/GSDME pathway and provides a rationale for combined treatment of MM with Bcl-2 and proteasome inhibitors to increase therapeutic efficiency via induction of pyroptosis.


Assuntos
Mieloma Múltiplo , Piroptose , Humanos , Piroptose/fisiologia , Inibidores de Proteassoma/farmacologia , Proteína X Associada a bcl-2/metabolismo , Caspase 3/metabolismo , Mieloma Múltiplo/tratamento farmacológico , Citocromos c/metabolismo
4.
BMC Geriatr ; 23(1): 564, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37715166

RESUMO

BACKGROUND: Fear of falling is a potential consequence for older adults who have experienced a fall. Whether such psychological concerns related to falls, in turn, affect physical function? Especially those who have a history of falling but have not been diagnosed with anxiety, depression, or both. This study aimed to clarify the effects of early psychological changes on the physical function of older patients. METHODS: The 111 participants with falling history were divided into the poor physical function (PPF) group with the Short Physical Performance Battery (SPPB) ≤ 9 and the good physical function (GPF) group with SPPB > 9. Their physical function was assessed through 4-m gait speed (4MGS), five times sit-to-stand test (FTSST), grip strength, and Timed Up and Go tests TUGT. Their mental state was assessed by the self-rating anxiety/depression scale (SAS/SDS). RESULTS: (1) SAS/SDS scores were negatively correlated with the SPPB score, gait speed, and maximum grip strength (males). (2) Multivariate logistic regression analysis showed that the SPPB score was subject to such independent influence factors: cerebrovascular disease (OR = 11.805; P = 0.005), normal ratio of grip strength (OR = 0.046; P = 0.016), TUGT (OR = 1.717; P < 0.001), and SDS score (OR = 1.154; P = 0.008). (3) The area under the ROC curve was 0.699 (0.601, 0.797) for SAS score, with a sensitivity of 0.776 and a specificity of 0.547; the AUC was 0.694 (0.596, 0.792) for SDS score, with a sensitivity of 0.586 and a specificity of 0.755. CONCLUSIONS: In older adults with a history of falls without a diagnosis of anxiety or depression, higher SAS/SDS scores were associated with worse fall-related physical function, and there was a statistically significant correlation between the two. This may indicate a risk of falling again in the future.


Assuntos
Acidentes por Quedas , Medo , Idoso , Masculino , Humanos , Acidentes por Quedas/prevenção & controle , Pacientes , Ansiedade/diagnóstico , Transtornos de Ansiedade
5.
Neural Plast ; 2023: 2382980, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37124873

RESUMO

Objective: Many stroke victims have severe swallowing problems. Previous neuroimaging studies have found that several brain regions scattered in the frontal, temporal, and parietal lobes, such as Brodmann's areas (BA) 6, 21, and 40, are associated with swallowing function. This study sought to investigate changes in swallowing function and resting-state functional magnetic resonance imaging (rs-fMRI) in stroke patients with dysphagia following action observation treatment. It also sought to detect changes in brain regions associated with swallowing in stroke patients. Methods: In this study, 12 healthy controls (HCs) and 12 stroke patients were recruited. Stroke patients were given 4 weeks of action observation therapy. In order to assess the differences in mfALFF values between patients before treatment and HCs, the fractional amplitude of low-frequency fluctuations (fALFF) in three frequency bands (conventional frequency band, slow-4, and slow-5) were calculated for fMRI data. The significant brain regions were selected as regions of interest (ROIs) for subsequent analysis. The mfALFF values were extracted from ROIs of the three groups (patients before and after treatment and HCs) and compared to assess the therapeutic efficacy. Results: In the conventional band, stroke patients before treatment had higher mfALFF in the inferior temporal gyrus and lower mfALFF in the calcarine fissure and surrounding cortex and thalamus compared to HCs. In the slow-4 band, there was no significant difference in related brain regions between stroke patients before treatment and HCs. In the slow-5 band, stroke patients before treatment had higher mfALFF in inferior cerebellum, inferior temporal gyrus, middle frontal gyrus, and lower mfALFF in calcarine fissure and surrounding cortex compared to HCs. We also assessed changes in aberrant brain activity that occurred both before and after action observation therapy. The mfALFF between stroke patients after therapy was closed to HCs in comparison to the patients before treatment. Conclusion: Action observation therapy can affect the excitability of certain brain regions. The changes in brain function brought about by this treatment may help to further understand the potential mechanism of network remodeling of swallowing function.


Assuntos
Transtornos de Deglutição , Acidente Vascular Cerebral , Humanos , Deglutição , Transtornos de Deglutição/diagnóstico por imagem , Transtornos de Deglutição/etiologia , Imageamento por Ressonância Magnética/métodos , Córtex Motor , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/terapia
6.
Cancer Sci ; 113(12): 4277-4288, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36056609

RESUMO

Owing to the complex anatomical structure and biomechanics, the current standard palliative treatments for cervical spinal metastases are associated with a high risk of recurrence and complications. Stereotactic body radiotherapy (SBRT) can provide radical dose to tumors while protecting normal organs to the maximum extent. However, the efficacy and safety of SBRT for cervical spinal metastases is not well characterized. Data from 71 patients with cervical spine metastases who were treated with SBRT using CyberKnife between 2006 and 2021 were obtained from our prospectively maintained database. Primary endpoint was pain response at 12 weeks following SBRT completion; secondary endpoints included local control (LC), overall survival (OS), and adverse events. Standard-risk patients were planned to receive 30 Gy (range 21-36) with median fractions of 3 (range 1-3) and high-risk patients 35 Gy (range 24-50) with median fractions of 5 (range 4-5) according to the spinal cord and esophagus dose constraints. The median follow-up time was 17.07 months (range 3.1-118.9). After 12 weeks of SBRT completion, 54 (98.2%) of 55 patients with baseline pain achieved pain response and 46 (83.6%) achieved complete pain response. LC rates were 93.1% and 90% at 1 year and 2 year, respectively. The 1-year and 2-year OS rates were 66.2% and 37.4%, respectively. Eight patients experienced grades 1-4 adverse events (six vertebral compression fracture [VCF], five of them had VCF before SBRT; and two hemiparesis). No grade 5 adverse events were observed. Therefore, risk-adapted SBRT for cervical spine metastases achieved high pain control and LC rates with acceptable adverse events.


Assuntos
Carcinoma , Fraturas por Compressão , Radiocirurgia , Fraturas da Coluna Vertebral , Neoplasias da Coluna Vertebral , Humanos , Radiocirurgia/efeitos adversos , Fraturas por Compressão/complicações , Neoplasias da Coluna Vertebral/radioterapia , Neoplasias da Coluna Vertebral/secundário , Fraturas da Coluna Vertebral/complicações , Dor/complicações
7.
Asia Pac J Clin Nutr ; 31(3): 561-569, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36173228

RESUMO

BACKGROUND AND OBJECTIVES: NutritionDay is a yearly global point-prevalence study of malnutrition or nutritional risk in hospitals. We aimed to provide a comprehensive nutritional survey of hospitalized patients and analyze the risk factors of malnutrition and prolonged hospitalization in Chinese inpatients. METHODS AND STUDY DESIGN: The international daylong cross-sectional survey was performed on November 07th, 2019. Ten hospitals were invited to participate in this NutritionDay survey. Nutritional risk was identified by nutritional risk screening 2002, and malnutrition was identified by the ESPEN criteria. We measured the incidence of malnutrition and nutritional risk. And we analysed risk factors for malnutrition and length of stay in Chinese hospitalized patients. RESULTS: 875 hospitalized patients from 6 departments were included in the analysis. The malnutrition rate was 11.6% and the incidence of nutritional risk was 17.8%. It was analyzed that tumor load, end-stage disease, motility, self-rated health, types of oral medicine, and food intake during the past week were independent risk factors for malnutrition or nutritional risk. 56.2% (118/210) of patients at nutritional risk or malnutrition received extra nutritional support, whereas 22.5% (88/391) well-nourished patients did. Moreover, nutrition status, ever stayed in ICU and self-rated health were associated with prolonged length of stay. CONCLUSIONS: In a word, the prevalence of malnutrition or nutritional risk was about 29.4%. Patients with malnutrition or nutritional risk had a higher transfer rate, lower rehabilitation rate and longer hospital stays. The attention to malnutrition patients needs to be further strengthened.


Assuntos
Pacientes Internados , Desnutrição , China/epidemiologia , Estudos Transversais , Hospitalização , Humanos , Tempo de Internação , Desnutrição/prevenção & controle , Avaliação Nutricional , Estado Nutricional , Prevalência , Fatores de Risco
8.
Molecules ; 27(17)2022 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-36080208

RESUMO

Berberine (BBR), a Chinese herbal medicine used in intestinal infection, has been applied as a botanical pesticide in the prevention of fungal disease in recent years. However, its degradation in the environment remains poorly understood. Here, we investigated BBR's degradation in soil water from different sources accompanied by its effect on bacterial diversity. Our results indicated that BBR was only degraded in soil water, while it was stable in tap water, river water and aquaculture water. Bacterial amplicon results of these samples suggested that the degradation of BBR was closely related to the enrichment of Methylotenera. To reveal this special relationship, we used bioinformatics tools to make alignments between the whole genome of Methylotenera and the pathway of BBR's degradation. An ortholog of Tetrahydroisoquinoline N-methyltransferase from plant was discovered only in Methylotenera that catalyzed a crucial step in BBR's degradation pathway. In summary, our work indicated that Methylotenera was an essential bacterial genus in the degradation of BBR in the environment because of its Tetrahydroisoquinoline N-methyltransferase. This study provided new insights into BBR's degradation in the environment, laying foundations for its application as a botanical pesticide.


Assuntos
Berberina , Praguicidas , Tetra-Hidroisoquinolinas , Metiltransferases/genética , Solo , Água
9.
Molecules ; 27(4)2022 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-35209217

RESUMO

The value of Agarwood increases with time due to the gradual release of its major components, but the mechanism behind this remains unclear. Herein we reveal that the potential driving force of this process is the degradation of cellulose in Agarwood by its saprophytic Bacillus subtilis. We selected 10-year-old Agarwood from different places and then isolated the saprophytic bacteria. We confirmed these bacteria from different sources are all Bacillus and confirmed they can degrade cellulose, and the highest cellulase activity reached 0.22 U/mL. By co-cultivation of the bacterium and Agarwood powder, we found that three of the strains could release the effective components of Agarwood, while they had little effect in increasing the same components in living Aquilaria sinensis. Finally, we demonstrated that these saprophytic Bacillus subtilis have similar effects on Zanthoxylum bungeanum Maxim and Dalbergiaod orifera T. Chen, but not on Illicium verum Hook. f, Cinnamomum cassia Presl and Phellodendron chinense Schneid. In conclusion, our experiment revealed that the saprophytic Bacillus release the effective components of Agarwood by degrading cellulose, and we provide a promising way to accelerate this process by using this bacterial agent.


Assuntos
Bacillus/crescimento & desenvolvimento , Celulose/metabolismo , Thymelaeaceae/microbiologia , Madeira/microbiologia
10.
Antimicrob Agents Chemother ; 65(10): e0089721, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34339268

RESUMO

Augmented renal clearance (ARC) can cause underexposure to vancomycin, thereby increasing the risk of treatment failure. Our objective was to evaluate population pharmacokinetics and optimize the dosing regimen of vancomycin in a pediatric population with ARC. Sparse pharmacokinetic sampling and therapeutic drug monitoring (TDM) data were collected from pediatric patients with ARC treated with vancomycin. A pharmacokinetic model was developed using NONMEM 7.2. The dosing regimen was optimized using Monte Carlo dose simulations. A total of 242 vancomycin serum concentrations from 113 patients (age range, 0.4 to 14.9 years; 49 females and 64 males) were available. The mean vancomycin dose was 58.8 mg/kg body weight/day (13.6 mg/kg/dose), and the mean vancomycin serum trough concentration was 6.5 mg/liter. A one-compartment pharmacokinetic model with first-order elimination was developed. Body weight and age were the most significant and positive covariates for clearance and volume of distribution. For the pediatric population with ARC, the current recommended vancomycin dose of 60 mg/kg/day was associated with a high risk of underdosing. To reach the target area under the concentration-time curve over 24 h in the steady state divided by the MIC (AUC/MIC) ratio of 400 to 700 in these pediatric patients, the vancomycin dose should be increased to 75 mg/kg/day for infants and children between 1 month and 12 years of age and 70 mg/kg/day for adolescents between 12 and 18 years of age. In conclusion, a one-compartment pharmacokinetic model with first-order elimination was established with body weight and age as significant covariates. An optimal dosing regimen was developed in pediatric patients with ARC aged 1 month to 18 years.


Assuntos
Antibacterianos , Vancomicina , Adolescente , Idoso , Área Sob a Curva , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Taxa de Depuração Metabólica , Método de Monte Carlo , Estudos Retrospectivos
11.
Pharmacol Res ; 170: 105694, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34087350

RESUMO

As an effective drug against acute enteritis diarrhea, Gegen Qinlian decoction (GQD) has a history of 2000 years. However, the potential molecular mechanism through which GQD could protect intestinal barrier from ulcerative colitis (UC) still remains undefined. As an important part of the homeostasis of the colon, gut microbiota is closely related to the dynamic evolution of the surrounding environment and the adjustment of dietary structure. At present, the effectiveness and mechanism of Jiawei Gegen Qinlian decoction against UC in different dietary environments are not clear. Here, the main active components of Jiawei Gegen Qinlian Decoction (PBM), were selected to construct a reasonable and effective compound scheme. We adopted "5% dextran sulfate sodium (DSS)" and "high temperature and humidity + high sugar and high fat + alcohol + 5%DSS" to induce UC rat models in general environment and UC rat models in Lingnan area, respectively. Then, we examined the therapeutic effects of PBM (89.96 mg/kg and 179.92 mg/kg) on two kinds of UC rats. The role of gut microbiota in the anti-UC effect of PBM was identified by intestinal flora consumption and fecal microbiota transplantation (FMT) experiments. Subsequently, we monitored the alterations of gut microbiota and fecal metabolism in the rat colon by 16Sr DNA technique and targeted metabonomics, respectively. The colon inflammation of the PBM-treated and the FMT-treated rats both showed significant relief, as evidenced by a reduction in body weight loss, bloody stool, diarrhea, disease activity index (DAI) score, shortening of colon length as well as decreased colon histology damage. Interestingly enough, the depletion of intestinal flora took away the protective effect of PBM, confirming the importance of intestinal flora in the anti-UC effect of PBM. Then our findings suggested that PBM could not only regulate the gut microbiota by increasing Akkermansia and Romboutsia but also decrease Escherichia-Shigella. More importantly, PBM could increase the production of propionate and total short-chain fatty acids (SCFAs) in colitis rats, regulate medium and long chain fatty acids (M-LCFAs), maintain bile acids (BAs) homeostasis, and regulate amino acids (AAs) metabolism. The transformation of intestinal environment might be related to the upregulation of anti-inflammation, anti-oxidation and tight junction protein expression in colonic mucosa. In summary, PBM showed potential for anti-UC activity through gut microbiota dependence and was expected to be a complementary and alternative medicine herb therapy.


Assuntos
Anti-Inflamatórios/farmacologia , Bactérias/efeitos dos fármacos , Colite Ulcerativa/tratamento farmacológico , Colo/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Fármacos Gastrointestinais/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Animais , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Colite Ulcerativa/metabolismo , Colite Ulcerativa/microbiologia , Colite Ulcerativa/patologia , Colo/metabolismo , Colo/microbiologia , Colo/patologia , Citocinas/metabolismo , Modelos Animais de Doenças , Disbiose , Feminino , Mediadores da Inflamação/metabolismo , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos Sprague-Dawley
12.
Proc Natl Acad Sci U S A ; 115(37): 9134-9139, 2018 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-30150399

RESUMO

Polycyclic aromatic hydrocarbon (PAH) molecules are essentially graphene in the subnanometer limit, typically consisting of 50 or fewer atoms. With the addition or removal of a single electron, these molecules can support molecular plasmon (collective) resonances in the visible region of the spectrum. Here, we probe the plasmon dynamics in these quantum systems by measuring the excited-state lifetime of three negatively charged PAH molecules: anthanthrene, benzo[ghi]perylene, and perylene. In contrast to the molecules in their neutral state, these three systems exhibit far more rapid decay dynamics due to the deexcitation of multiple electron-hole pairs through molecular plasmon "dephasing" and vibrational relaxation. This study provides a look into the distinction between collective and single-electron excitation dynamics in the purely quantum limit and introduces a conceptual framework with which to visualize molecular plasmon decay.

13.
Ecotoxicol Environ Saf ; 213: 112042, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33607336

RESUMO

Aluminum (Al) toxicity severely decreases plant growth and productivity in acidic soil globally. Ectomycorrhizal (ECM) fungi can promote host plant's Al-tolerance by acting as a physical barrier or bio-filter. However, little information is available on the role of ECM fungus on Al immobilization with respect to Al-tolerance. This present study aimed to screen a promising indigenous ECM fungus with high Al-tolerance and to understand its role in Al immobilization related to Al-tolerance. Two ECM fungal strains (Lactarius deliciosus 2 and Pisolithus tinctorius 715) isolated from forest stands in Southwest China were cultured in vitro with 0.0, 1.0 or 2.0 mM Al addition for 21 days to compare their Al accumulation and Al-tolerance. Meanwhile, fungal mycelia were incubated in 0.037 mM Al3+ solutions, and then Al3+ concentrations in the solution were determined at time 2, 5, 10, 20, 40, 60, 120, 180, and 240 min, and the Al3+ immobilization characteristics were evaluated using the pseudo-first order, pseudo-second order and intraparticle diffusion models. Results showed that 1.0 or 2.0 mM Al3+ addition significantly increased fungal biomass production by 23% or 41% in L. deliciosus 2, not in P. tinctorius 715. Fungal Al3+ concentrations in L. deliciosus 2 and P. tinctorius 715 were significantly increased by 293% and 103% under 2.0 mM than under 1.0 mM Al3+ addition. The pH values in the culture solution were significantly decreased by 0.43 after 21 d fungus growth but no changes between these two fungi under the same Al3+ addition. Fungal Al3+ immobilization showed a three-stage trend with initially a rapid rate followed a relatively slower rate until reaching equilibrium. The pseudo-second order model was the best (R2 = 0.98 and 0.99 for L. deliciosus 2 and P. tinctorius 715) to fit the experimentally observed data among the three models. Compared to P. tinctorius 715, L. deliciosus 2 also had greater intercept value, cation exchange capacity (CEC), and extracellular Al3+ proportion in fungal mycelia. Additionally, bio-concentration on Al3+, active site numbers for Al3+, boundary layer thickness, CEC, and immobilization on the cell wall in fungal mycelia were involved in ECM fungal Al-tolerance. These results show that both ECM fungi are Al-tolerant while L. deliciosus 2 is a promising indigenous ECM isolate with higher Al-tolerance in Southwest China, and they can be hence applied to the afforestation and ecological restoration in acidic soil.


Assuntos
Alumínio/metabolismo , Basidiomycota/fisiologia , Poluentes do Solo/metabolismo , Agaricales , Basidiomycota/crescimento & desenvolvimento , Biodegradação Ambiental , Biomassa , China , Florestas , Micélio/crescimento & desenvolvimento , Micorrizas/crescimento & desenvolvimento , Micorrizas/fisiologia , Solo/química , Microbiologia do Solo
14.
Appl Environ Microbiol ; 86(8)2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32060022

RESUMO

Plant growth is often limited by highly activated aluminum (Al) and low available phosphorus (P) in acidic soil. Ectomycorrhizal (ECM) fungi can improve their host plants' Al tolerance by increasing P availability while decreasing Al activity in vitro or in hydroponic or sand culture systems. However, the effect of ECM fungi on inorganic P (IP) and labile Al in acidic soil in the field, particularly in conjunction with Al treatment, remains poorly understood. The present study aimed to determine the influence of ECM fungal association on the mobilization of IP and labile Al in rhizosphere soil of host plants grown in the field with external Al treatment and the underlying nutritional mechanism in plant Al tolerance. To do so, 4-week-old Pinus massoniana seedlings were inoculated with three ECM isolates (Laccaria bicolor 270, L. bicolor S238A, and L. bicolor S238N) and grown in a Haplic Alisol field with or without Al treatment for 12 weeks. Results showed that L. bicolor association enhanced the available P depletion and facilitated the mobilization of IP and labile Al, in turn improving the capacity of host plant to use Al-bound P, Ca-bound P, and occluded P, particularly when P. massoniana seedlings were inoculated with L. bicolor S238A. Inoculation with L. bicolor isolates also enhanced the solubility of labile Al and facilitated the conversion of acid-soluble Al into exchangeable Al. Our findings suggested that ECM inoculation could enhance plant Al tolerance in the field by mobilizing IP to improve the P bioavailability but not by decreasing Al activity.IMPORTANCE Here, we reveal the underlying nutritional mechanism in plant Al tolerance conferred by ectomycorrhizal (ECM)-fungus inoculation in the field and report the screening of a promising ECM isolate to assist phytoremediation and afforestation using Pinus massoniana in acidic soil in southern China. This study advances our understanding of the contribution of ECM fungi to plant-ECM-fungus symbiosis and highlights the vital role of ECM-fungus inoculation in plant Al tolerance. In addition, the results described in the present study confirm the importance of carrying out studies in the field rather than only in vitro studies. Our findings strengthen our understanding of the role of ECM-fungus association in detecting, utilizing, and transporting unavailable nutrients in the soil to enhance host plant growth and adaptability in response to adverse habitats.


Assuntos
Alumínio/metabolismo , Laccaria/metabolismo , Fosfatos/metabolismo , Pinus/crescimento & desenvolvimento , Microbiologia do Solo , Solo/química , China , Rizosfera , Plântula/crescimento & desenvolvimento
15.
Appl Opt ; 59(13): 3952-3958, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32400666

RESUMO

Monomer diffusion models are important in describing the formation mechanism of the volume holographic grating in photopolymers. The most representative of these models is the first-order diffusion model, which neglects the influence of the exposure intensity threshold and dissolved oxygen in a polymer. This model causes a significant deviation between the theoretical simulation and the experimental results. Therefore, we propose a modified monomer diffusion model, which is more consistent with experimental results on refractive index modulation than other models.

16.
Proc Natl Acad Sci U S A ; 113(20): 5558-63, 2016 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-27140618

RESUMO

The optical properties of metallic nanoparticles with plasmon resonances have been studied extensively, typically by measuring the transmission of light, as a function of wavelength, through a nanoparticle suspension. One question that has not yet been addressed, however, is how an image is transmitted through such a suspension of absorber-scatterers, in other words, how the various spatial frequencies are attenuated as they pass through the nanoparticle host medium. Here, we examine how the optical properties of a suspension of plasmonic nanoparticles affect the transmitted image. We use two distinct ways to assess transmitted image quality: the structural similarity index (SSIM), a perceptual distortion metric based on the human visual system, and the modulation transfer function (MTF), which assesses the resolvable spatial frequencies. We show that perceived image quality, as well as spatial resolution, are both dependent on the scattering and absorption cross-sections of the constituent nanoparticles. Surprisingly, we observe a nonlinear dependence of image quality on optical density by varying optical path length and nanoparticle concentration. This work is a first step toward understanding the requirements for visualizing and resolving objects through media consisting of subwavelength absorber-scatterer structures, an approach that should also prove useful in the assessment of metamaterial or metasurface-based optical imaging systems.

17.
Zhongguo Dang Dai Er Ke Za Zhi ; 21(9): 904-909, 2019 Sep.
Artigo em Zh | MEDLINE | ID: mdl-31506151

RESUMO

OBJECTIVE: To investigate the effect of augmented renal clearance (ARC) on plasma concentration of vancomycin, bacteriological outcome, and clinical outcome in children with methicillin-resistant Staphylococcus aureus (MRSA) infection treated by vancomycin. METHODS: A retrospective analysis was performed for the clinical data of 60 critically ill children who were treated with vancomycin due to MRSA infection from January 2013 to July 2017 and underwent plasma concentration monitoring. According to estimated glomerular filtration rate, these children were divided into an ARC group with 19 children and a normal renal function group with 41 children. The two groups were compared in terms of the use of vancomycin, plasma concentration of vancomycin, and treatment outcome. RESULTS: The children in the ARC group had an age of 1-12 years, and the ARC group had significantly higher body weight and body surface area than the normal renal function group (P<0.05). Compared with the normal renal function group, the ARC group had a significantly lower initial trough concentration of vancomycin and a significantly lower proportion of children who achieved the effective trough concentration of vancomycin (10-20 mg/L) (P<0.05). There were no significant differences in bacteriological outcome and clinical outcome between the two groups (P>0.05), but the ARC group had significantly longer length of stay in the pediatric intensive care unit (PICU) and length of hospital stay than the normal renal function group (P<0.05). CONCLUSIONS: ARC can significantly reduce the trough concentration of vancomycin and prolong the length of PICU stay and the length of hospital stay in children with MRSA infection. Idividualized medication should be administered to children with ARC.


Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Vancomicina/uso terapêutico , Antibacterianos , Criança , Pré-Escolar , Humanos , Lactente , Meticilina , Estudos Retrospectivos , Infecções Estafilocócicas/tratamento farmacológico , Resultado do Tratamento
18.
Oecologia ; 188(3): 921-929, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30143873

RESUMO

Atmospheric nitrogen (N) deposition reduces plant diversity. However, it often remains unclear how dominant species and litter accumulation feedbacks mediate N-induced plant diversity declines. We tested mechanisms of N-induced diversity change through dominant grasses and litter in a 7-year field experiment. Nitrogen addition reduced species richness, Shannon-Wiener diversity (H') and evenness from the second to the fourth year, however, surprisingly, increased them in the sixth and seventh year. The reversal in the response of diversity to N addition was explained by changes in grass dominance and standing litter accumulation. The diversity recovery during later years in fertilized plots was attributed to a decrease in the dominant grass and an increase in standing litter: standing litter reduced bud numbers of the dominant grass by decreasing light availability. The decreased light availability by standing litter reduced completion from the dominant species, which resulted in diversity increase. The negative feedback between dominant grasses and standing litter led to transient N-induced diversity loss in the short-term, but recovery of plant diversity in the long-term. Grassland management that affects litter accumulation, such as firing, grazing and mowing, can therefore, have substantial effects on the long-term response of plant diversity to N deposition.


Assuntos
Nitrogênio , Poaceae , Ecossistema , Plantas
19.
Nano Lett ; 16(10): 6390-6395, 2016 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-27668447

RESUMO

Charged polycyclic aromatic hydrocarbons (PAHs), ultrasmall analogs of hydrogen-terminated graphene consisting of only a few fused aromatic carbon rings, have been shown to possess molecular plasmon resonances in the visible region of the spectrum. Unlike larger nanostructures, the PAH absorption spectra reveal rich, highly structured spectral features due to the coupling of the molecular plasmons with the vibrations of the molecule. Here, we examine this molecular plasmon-phonon interaction using a quantum mechanical approach based on the Franck-Condon approximation. We show that an independent boson model can be used to describe the complex features of the PAH absorption spectra, yielding an analytical and semiquantitative description of their spectral features. This investigation provides an initial insight into the coupling of fundamental excitations-plasmons and phonons-in molecules.

20.
Zhongguo Dang Dai Er Ke Za Zhi ; 19(3): 342-345, 2017 Mar.
Artigo em Zh | MEDLINE | ID: mdl-28302209

RESUMO

OBJECTIVE: To investigate the accuracy and clinical utility of neonatal critical illness score (NCIS) and score for neonatal acute physiology, perinatal extension, version II (SNAPPE-II) in predicting the "dead and abandoned" risk in critically ill neonates. METHODS: A total of 269 critically ill neonates were divided into two groups according to their prognosis: dead/abandoned and improved/cured. The accuracy of these two scoring systems, NCIS and SNAPPE-II, in predicting the "dead and abandoned" risk was compared. RESULTS: The dead/abandoned group had a significantly higher SNAPPE-II score than the improved/cured group (P<0.001), while there was no significant difference in the NCIS score between the two groups (P=0.091). The children who were in line with the individual indicator in the NCIS results had a significantly higher "dead and abandoned" risk than those who were not (P=0.005). CONCLUSIONS: SNAPPE-II is more accurate in early prediction of the "dead and abandoned" risk in critically ill neonates compared with NCIS. NCIS has the ability to predict the "dead and abandoned" risk in children in line with the individual indicator.


Assuntos
Estado Terminal , Recém-Nascido/fisiologia , Feminino , Humanos , Masculino , Estudos Retrospectivos , Índice de Gravidade de Doença
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